Optical Communication Systems Modulation and Multiplexing In

Home , Modulated ultrasound, Multiplexing, Phase modulation

February 2009 Vol. 23, No. 1 www.i-LEOS.org IEEE NEWS

THE SOCIETY FOR PHOTONICS Modulation and multiplexing in Optical Communication Systems

WDM

Frequency WDM with Polarization Interleaving

x-pol

Frequency y-pol

WDM with Polarization Multiplexing

x-pol

Frequency y-pol

Page 6, Fig. 4. Orthogonality through disjoint frequency bins (WDM) can be combined with orthogonality in the polarization dimension.

February 2009 Volume 23, Number 1

FEATURES

Research Highlights: ...... 4 – “Modulation and Multiplexing in Optical Communication Systems,” by Peter J. Winzer – “Electronic Signal Processing for Fiber-Optic Communications,” by John Cartledge et al – “Radio over Fiber Distributed Antenna Networks,” by Michael J. Crisp et al – “Enabling Microwave Photonic Technologies for Antenna Remoting,” by Dalma Novak

DEPARTMENTS

News ...... 26 • 2009 IEEE/LEOS Fellows • 2009 IEEE/LEOS Award Reminders: William Streifer Scientific Achievement Award, Engineering Achievement Award, Aron Kressel Award, and Distinguished Service Award 4 • Call for Fellow Nominations • Nomination Form for IEEE/LEOS Awards Careers ...... 30 • 2008 LEOS Student Paper Award Recipients • 2009 IEEE/LEOS Young Investigator Award Recipient: Aydogan Ozcan • 2009 IEEE David Sarnoff Award Recipients: Yasuhiko Arakawa, Kerry John Vahala, and Kam Yin Lau Membership ...... 34 • Chapter Highlight: Italy Chapter • Benefits of IEEE Senior Membership 15 • New Senior Members Conferences...... 36 • 2008 LEOS Awards and Recognition • “International Conference on Advanced Optoelectronics and Lasers” by Igor A. Sukhoivanov • 20th Annual Workshop on Interconnections Within High Speed Digital Systems – 2009 • The Optical Data Storage Topical Meeting – 2009 • IPRM – 2009 • IEEE/LEOS International Conference on Optical MEMS & HUB3G WLAN 17 Nanophotonics – 2009 Publications ...... 47 • Call for Papers: – IEEE Journal of Selected Topics in Quantum Electronics (JSTQE) 22

COLUMNS Editor’s Column...... 2 President’s Column ...... 3

February 2009 IEEE LEOS NEWSLETTER 1 Editor’s IEEE Lasers and Column Electro-Optics Society KRISHNAN PARAMESWARAN President Membership & Regional Activities - John H. Marsh A. Helmy Welcome to the first LEOS Newsletter of 2009! Dept of E & E Engineering Publications - R. Tucker Last year was tumultuous in many respects through- Rankine Building Technical Affairs - A. Seeds University of Glasgow out the world. The Photonics industry will certainly play Glasgow G12 8LT, Scotland, UK. Newsletter Staff a positive role in the eventual economic revival. As most Tel: +44 141 330 4901 Fax: +44 141 330 4907 Executive Editor of you know, LEOS will change its name to the IEEE E-mail: [email protected] Krishnan R. Parameswaran Photonics Society this year. This name change certainly Physical Sciences Inc. 20 New England Business Center President-Elect Andover, MA 01810 reflects the focus of those who work in our field − let us James Coleman Tel: +1 978 738 8187 Dept. of E & C Engineering hope that it signals the start of a successful year for our Email: [email protected] field and the economy as a whole! University of Illinois 208 N Wright Street Associate Editor of Asia & Pacific We have four feature articles this month, all with the Urbana, IL 61801-2355 Hon Tsang general theme of optical communications. Two articles Tel: +1 217 333 2555 Dept. of Electronic Engineering E-mail: [email protected] The Chinese University of Hong Kong focus on optical fiber systems. Peter Winzer of Bell Labs Shatin, Hong Kong describes modulation and multiplexing formats, and Past-President Tel: +852 260 98254 Alan Willner Fax: +852 260 35558 John Cartledge and colleagues at Queen’s University and University of Southern California Email: [email protected] Nortel Networks in Canada have written a nice piece on Dept. of EE-Systems/Rm EEB 538 Los Angeles, CA 90089-2565 Associate Editor of Canada electronic signal processing for fiber communications. Tel: +1 213 740 4664 Lawrence R. Chen The other two articles discuss antenna networks. Michael Fax: +1 213 740 8729 Department of Electrical & Email: [email protected] Computer Engineering Crisp and co-workers at the University of Cambridge McConnell Engineering Building, Rm 633 Secretary-Treasurer discuss radio-over-fiber distributed antenna networks, McGill University Jerry Meyer 3480 University St. while Dalma Novak of Pharad discusses microwave Naval Research Laboratory Montreal, Quebec Code 5613 photonic technology. Canada H3A-2A7 In Membership News, chair of the LEOS Italian Washington, DC 20375-0001 Tel: +514 398 1879 Tel: +1 202 767 3276 Fax: 514-398-3127 Chapter (2008 LEOS and IEEE Region 8 chapter of the E-mail: [email protected] Email: [email protected] year) Tiziana Tambosso has contributed an article describ- Executive Director Associate Editor of Europe/Mid East/ ing activities in the Italian LEOS Chapter. The breadth Richard Linke Africa of activities there should inspire all of us to get involved IEEE/LEOS Kevin A. Williams 445 Hoes Lane Eindhoven University of Technology in our local sections. Finally, we have a nice piece from Piscataway, NJ 08855-1331 Inter-University Research Institute Prof. Igor Sukhoivanov of the Ukraine Chapter describ- Tel: +1 732 562 3891 COBRA on Communication Fax: +1 732 562 8434 Technology ing a conference held there last fall. Email: [email protected] Department of Electrical Engineering As always, please feel free to send any comments and PO Box 513 Board of Governors 5600 MB Eindhoven, The Netherlands Email: [email protected] suggestions to [email protected]. I would love S. L. Chuang C. Gmachl K. Hotate J. Jackel to hear what you would like to see in the Newsletter this Staff Editor J. Kash T. Koonen Giselle Blandin year. I wish everyone a happy and prosperous 2009! M. Lipson J. Meyer IEEE/LEOS D. Plant A. Seeds 445 Hoes Lane Regards, P. W i n ze r I . Wh ite Piscataway, NJ 08855-1331 Tel: +1 732 981 3405 Krishnan Parameswaran Vice Presidents Fax: +1 732 562 8434 Conferences - D. Rabus Email: [email protected] Finance & Administration - F. Bartoli

LEOS Newsletter is published bimonthly by the Lasers and Electro- Optics Society of the Institute of Electrical and Electronics Engineers, Inc., Corporate Office: 3 Park Avenue, 17th Floor, New York, NY 10017-2394. Printed in the USA. One dollar per member per year is included in the Society fee for each member of the Lasers and Electro-Optics Society. Periodicals postage paid at New York, NY and at additional mailing offices. Postmaster: Send address changes to LEOS Newsletter, IEEE, 445 Hoes Lane, Piscataway, NJ 08854. Copyright © 2009 by IEEE: Permission to copy without fee all or part of any material without a copyright notice is granted provided that the copies are not made or distributed for direct commercial advantage, and the title of the publication and its date appear on each copy. To copy material with a copyright notice requires specific permission. Please direct all inquiries or requests to IEEE Copyrights Office.

2 IEEE LEOS NEWSLETTER February 2009 President’s Column JOHN H. MARSH

I would like to start by wishing you all a (belated by the time it for and familiarity with the existing name, and LEOS does have reaches you) Happy New Year. The New Year is traditionally a strong brand recognition within the field. However, the ques- time for renewal and change, and 2009 will certainly see many tions are whether the new name better describes the field in changes for the Society. which we work, and whether it will better enable to us to realize the Society’s vision. The results of the membership survey are A new name very clear. Moreover, this is not the first time the Society has As you will be aware, we have recently addressed the name of the changed its name – it was first founded as QEAS (the Quan- Society, and whether a new name would better describe the field tum Electronics and Applications Society), before adopting the of interest or would assist the Society in realizing its vision. name LEOS. The Society’s field of interest is: I personally believe the IEEE Photonics Society will be much ‘lasers, optical devices, optical fibers, and associated lightwave more widely recognized than LEOS. Even within IEEE – even technology and their applications in systems and subsystems in which within TAB itself with its 38 Societies and 7 Technical Councils – quantum electronic devices are key elements’, the LEOS acronym is not universally recognized! The societies and the vision for the Society is: that are well recognized usually have single word names – Com- ‘to be the primary forum where critical and fundamental advances puter, Communications, Reliability, Education – and are known in the field are shared, nurtured and coupled to developments in related by these names rather than by a collection of letters (though the disciplines’. Communications Society is generally known as ComSoc). These The membership survey conducted last year demonstrated names also have meanings understood throughout the engineer- overwhelming support for changing the name of the Society. ing and scientific professions, and, significantly, by the wider Key results from the survey are as follows: public. Photonics is a single word that encompasses the field of • 38% of members and 15% of non-members participated our Society, and adopting this name gives us the opportunity to • 82% of respondents said Photonics represents their work be more widely recognized and to be more effective in outreach. well, compared to 52% for LEOS • 75% of respondents said Photonics would be well-understood Changes in the society leadership by those not in the field, compared to only 22% for LEOS Entering 2009, there are significant changes to the Society • 74% of respondents indicated that the IEEE Photonics leadership. We have a new President-Elect and several Vice- Society would better represent the activities of the Society Presidents have retired. than IEEE-LEOS. I am delighted to inform you that James Coleman (Univer- Given the high level of participation and the clear responses sity of Illinois) was chosen as President-Elect at the November from the survey, the Board of Governors voted unanimously BoG meeting. He will become President in January 2010. for a change in the name of the Society. At the IEEE Meeting The new Vice-Presidents are: Series in November, I presented a motion for the change in • Conferences Dominik Rabus (Buerkert name to the IEEE Society Presidents’ Forum which gave its Werke GmbH, Germany) unanimous support – the results of the survey being a clear fac- • Finance and Administration Fil Bartoli (Lehigh tor in gaining this approval. The following day, the full IEEE University, Pennsylvania) Technical Activities Board also gave its unanimous approval. • Publications Rod Tucker (University Any change to the Society’s Constitution also requires a of Melbourne, Australia) membership consultation, followed by a ballot if more than • Secretary/Treasurer Jerry Meyer (Naval 5% of the membership requests this. The consultation period Research Laboratory, DC) ended on 30th December, and I am pleased to inform you that Amr Helmy (University of Toronto, Canada) and Alwyn Seeds there have been no requests for a ballot, and only one member (UCL, United Kingdom) continue to serve as VP Membership has indicated unhappiness with the change. and Region Affairs and VP Technical Activities respectively. One of the most striking changes that will therefore happen I would like to thank the retiring VPs for their tireless work in 2009 is that LEOS will become the IEEE Photonics Society. for the Society over the last three years – Katya Golovchenko The new name now has approval and support from the Board (Conferences), Steve Newton (Finance and Administration), of Governors, the IEEE Technical Activities Board and, most Fil Bartoli (Secretary/Treasurer). importantly, the membership. The remaining step is formal I would also like to thank Carmen Menoni, who retired from approval by the IEEE Board of Directors, which is expected in Publications after only two years so she could take up the post February. The new name will be introduced thereafter. of Editor in Chief of the new IEEE Photonics Journal. There will On an issue as sensitive as the name of the Society, there will always be a divergence of views. In particular, there is affection (continued on page 25)

February 2009 IEEE LEOS NEWSLETTER 3 Research Highlights Modulation and multiplexing in optical communication systems Peter J. Winzer

BELL LABS, ALCATEL-LUCENT, HOLMDEL, NJ 07733 higher. In free-space systems optical beams have much smaller divergence angles than in the microwave regime1, at the expense of significantly exacerbated antenna pointing requirements, Digital electronics and optical transport though. The narrow beam width favorably translates into the The rapid transition from analog to digital systems over the past system’s link budget, in particular in space-based systems where ~50 years has enabled universal processing of all kinds of informa- atmospheric absorption is less of a problem. Apart from the tion, fundamentally without loss of quality [1]. Breakthroughs above two major advantages, other considerations sometimes in digital semiconductor technologies and their enormous abil- come into play, such as the unregulated spectrum in the optical ity to scale [2] have enabled cost-effective mass-production of regime or the absence of electromagnetic interference. richly functional yet highly reliable and power-efficient micro- chips that are found in virtually any electronic device today, from The gradual replacement of high-end internet routers to low-end consumer electronics. electronic transport Closely coupled to the generation, processing, and storage The suitability of optical communications for different sys- of digital information is the need for data transport, ranging tem scenarios can be further analyzed using the three basic from short on-chip [3] and board-level [4,5] data buses all the transponder characteristics shown in Fig. 2: A transponder’s way to long-haul transport networks spanning the globe [6,7] sensitivity measures the minimum power (or the minimum and to deep-space probes collecting scientific data [8], cf. Fig. 1 signal-to-noise ratio) required by the receiver to close a digi- [5,10]. Each of these very different applications brings its own tal communication link, which impacts the link distance that set of technical challenges, which can be addressed using elec- may be bridged. In this loosely defined context, the term “sen- tronic, radio-frequency (RF), or optical communication systems. sitivity” also includes the effect of linear and nonlinear signal Among the different communication technologies, optical com- distortions due to the transmission channel. The capacity of munications generally has the edge over baseband electronic or a system measures the amount of data that can be transmit- RF transmission systems whenever high aggregate bit rates and/or ted over the communication medium. Here, we think of the long transmission distances are involved. Both advantages are deep- capacity per waveguide, with the understanding that parallel ly rooted in physics: First, the high optical carrier frequencies lanes (buses) are likely to be used in applications that require allow for high-capacity systems at small relative bandwidths. high aggregate capacities at tight transponder integration re- For example, a mere 2.5% bandwidth at a carrier frequency of quirements. In many applications, implementation aspects of a 193 THz (1.55 µm wavelength) opens up a 5-THz chunk of transponder (including its physical dimensions, power con- continuous communication bandwidth. Such “narrow-band” sumption, cost, and reliability) are the most critical param- systems are much easier to design than systems with a large rela- eters and often delay the entrance of optics into a particular tive bandwidth. Second, transmission losses at optical frequen- application space. The figure roughly indicates the relative cies are usually very small compared to baseband electronic or RF technologies. Today’s optical telecommunication fibers exhibit 1 The divergence angle of an antenna of diameter D operating at wavelength losses of less than 0.2 dB/km; the loss of typical coaxial cables l is given by l/D. At 1µm, a telescope (=antenna) of 10 cm diameter has a supporting ~1 GHz of bandwidth is 2 to 3 orders of magnitude divergence angle of 10 µrad (50.6 mdeg).

GEO, LEO Terrestrial Networks Rack-to-Rack Chip-to-Chip Deep-Space Submarine Access Backplanes On-Chip

100,000 km 1,000 km 10 km 100 m 1 m 1 cm

Figure 1. Digital communication distances can be over 100,000 km in deep-space missions and below 1 mm on-chip. (GEO: Geostationary satellite orbit; LEO: Low-Earth satellite orbit.) Figures reproduced with permission. From left to right, courtesy of (1) NASA/JPL-Caltech; (2) European Space Agency (ESA); (3) Alcatel-Lucent; (4) Alcatel-Lucent [11]; (5) Corning, Inc. [9]; (6) – (9) IBM [3].

4 IEEE LEOS NEWSLETTER February 2009 importance of the three performance metrics for different communication applications. Capacity Sensitivity Deep-Space As bandwidth demands have continuously increased and as Submarine opto-electronic device and integration technologies have ad- Terrestrial GEO, LEO vanced, optical communications has gradually replaced elec- Long-Haul tronic (and to some extent directional2 microwave) solutions. Metro and Terrestrial This process started on a large scale in the late 1970s and 1980s Regional Free-Space at the most demanding high-bandwidth/long-distance appli- Access cations of terrestrial [6] and submarine [7] transport. With LAN, SAN massive fiber-to-the-home (FTTH) deployments now under- way world-wide, optics is currently capturing the access space Rack-to-Rack [9], and rack-to-rack interconnects are starting to become opti- Backplane cal [3]. The red application areas in Fig. 2 indicate well estab- Chip-to-Chip lished optical communication technologies. The applications On-Chip marked orange denote areas where optics can be found but is not yet used on a massive scale. The blue applications are still Implementation dominated by electronics, with research on optical successors Figure 2. Sensitivity, capacity, and implementation aspects (physi- being actively pursued. Despite the continuing improvement cal dimensions, power consumption, and cost) are key factors be- in electronic transmission techniques [12], optical solutions hind the success of any communication technology. Starting from are expected to enter backplanes, paving the way to optical “high sensitivity / high capacity” applications (terrestrial and sub- chip-to-chip and, eventually, on-chip communications once marine long-haul), optical communications is steadily replacing electronic transmission can no longer keep pace with the grow- electronic transmission technologies. ing need for communication capacity, power consumption, or “escape bandwidth”, i.e., the interconnect capacity per unit of [16]. If signals leak energy into neighboring frequency bins, interface area [3,4,5]. At the same time, areas where optical orthogonality is degraded and perfect reconstruction is no lon- communications is already well established have to continue ger possible (‘WDM crosstalk’). As shown in Fig. 4, a possible supporting ever-increasing capacity demands. counter-measure, which has been used in some research demonstrations, is alternating the polarization of adjacent chan- Orthogonal dimensions and multiplexing nels to re-establish orthogonality in the polarization dimension In order to meet the application-specific requirements on sen- (‘polarization interleaving’). sitivity and capacity under the respective implementation con- Using true polarization-division multiplexing (PDM, cf. Fig. 4), straints, one has to choose the best suited modulation and mul- one sends two independent signals on both orthogonal polar- tiplexing techniques based on the available physical dimensions izations supported by a single-mode optical fiber. In order to shown in Fig. 3 [13]. recover these polarization-multiplexed bit streams, one either Of particular importance in this context is the notion of uses a polarization beam splitter whose axes are constantly kept orthogonality [15]. Loosely speaking3, two signals are orthogo- aligned with the signal polarizations (‘polarization control’), nal if messages sent in these two dimensions can be uniquely or one detects two arbitrary orthogonal polarizations (‘polar- separated from one another at the receiver without impacting ization diversity’) using coherent detection. Since upon fiber each other’s detection performance. This way, independent bit transmission the polarization axes at the receiver will be ran- streams can share a common transmission medium, which is re- domly rotated compared to the transmitter, one electronically ferred to as multiplexing. The amount of individual bit streams back-rotates the detected signals using the (estimated) inverse that can be packed onto a single transmission medium deter- Jones matrix of the transmission channel. This is the approach mines a system’s aggregate capacity. The most advanced multi- taken by modern coherent receivers [16]. plexing techniques are therefore found in capacity-constrained Another way of achieving orthogonality in the frequency systems, such as long-haul fiber-optic transport (cf. Fig. 2). domain is by letting the signal spectra at adjacent wavelengths Multiplexing is performed by exploiting orthogonality overlap but choosing the frequency spacing to be exactly in one or more of the physical dimensions shown in Fig. 3. 1/TS, where TS is the symbol duration, synchronized across the Sending signals in disjoint frequency bins on different optical individual (sub)carriers. This approach is visualized in time carrier frequencies is called wavelength-division multiplexing and frequency domain in Fig. 5. Although the superposition (WDM), cf. Fig. 4. Such signals are orthogonal, and individ- of the three modulated signals (examples shown are ‘11213’ ual bit streams can be recovered using optical bandpass filters and ‘12213’) looks unintelligible at a first glance, a receiver or electronic filters following a coherent receiver front-end can uniquely filter out the information transported by each subcarrier by first multiplying the superposition with a sine wave of the desired subcarrier’s frequency and then integrating over the 2 Owing to the inherently high directionality of optical antennas, microwave symbol duration. This operation can be particularly efficiently systems will likely continue to be the solution of choice for mobile environments requiring omni-directional reception and transmission. done in the electronic domain using the fast Fourier transform 3 A rigorous definition of orthogonality in the context of optical communi- (FFT). This kind of multiplexing is known as orthogonal fre- cations is given in, e.g., [13,14]. quency division multiplexing (OFDM) [17] or coherent WDM

February 2009 IEEE LEOS NEWSLETTER 5 Pol.Multiplexing WDM Separate Fibers PolSK Pol.Interleaving OFDM FSK, MSK Multiple Modes Mod Mux CoWDM Mux Mod

Mux Polarization Space Frequency oCDMA Physical Dimensions for Modulation and Multiplexing Mux PPM Mod Time Code ETDM Quadrature OTDM Mux Amplitide / Phase Modulation

Im{ } Im{ } Im{ } Ex Ex Ex

{ } { } { } Re Ex Re Ex Re Ex

QPSK 8-PSK 16-QAM

Figure 3. Physical dimensions that can be used for modulation and multiplexing in optical communications. (OTDM: Optical time- division multiplexing; ETDM: Electronic time-division multiplexing; oCDMA: Optical code-division multiple access; PPM: Pulse position modulation; PolSK: Polarization shift keying; FSK: Frequency-shift keying; MSK: Minimum-shift keying; WDM: Wavelength-division multiplexing; CoWDM: Coherent WDM; OFDM: Orthogonal frequency-division multiplexing; PSK: Phase shift keying; QPSK: Quadra-

ture PSK; QAM: Quadrature amplitude modulation; Ex: Optical field (x polarization).)

WDM 1/Ts

Frequency Frequency WDM with Polarization Interleaving

T x-pol s t tt Frequency y-pol 1 2 3

WDM with Polarization Multiplexing tt x-pol 1 + 2 + 3 1 - 2 + 3 Frequency

y-pol Figure 5. Orthogonal frequency spacings of 1/TS lead to OFDM or CoWDM. Figure 4. Orthogonality through disjoint frequency bins (WDM) can be combined with orthogonality in the polarization dimension. implementation-constrained systems (rack-to-rack interconnects and shorter), where frequency stable lasers and filters (CoWDM) [18,19], depending on whether the (de)multiplexing operating over a significant temperature range lead to bulky operations are performed electronically or optically (equivalent and power-consuming solutions, and coherent signal process- to the distinction between ETDM and OTDM in the time do- ing becomes problematic for the same reasons. Here, coarse main). If the orthogonal waveforms are not sine waves but or- WDM (CWDM) with uncooled components allows for chan- thogonal sequences of short pulses (“chips”), we arrive at optical nel spacings of typically 20 nm and can be an attractive multi- code-division multiple access (oCDMA) [20]. plexing solution. In contrast, for long-haul transport systems, Finally, one can make use of the spatial dimension, in its which are the most capacity-constrained systems existing to- most obvious form by sending different signals on parallel day, spatial multiplexing is not cost efficient, and dense WDM optical waveguides, sometimes referred to as spatial multiplex- is a requirement, recently even in combination with PDM. ing. Using parallel waveguides is particularly attractive for The key parameter characterizing such systems is the spectral

6 IEEE LEOS NEWSLETTER February 2009 efficiency (SE), defined as the ratio of per-channel bit rate to WDM channel spacing. OOK

Modulation and coding 1 0011000 11 Intensity Modulation denotes the method by which digital information is Time imprinted onto an optical carrier, and in its most general sense also includes coding to prevent transmission errors from occur- π PSK ring (‘line coding’) or to correct for already occurred transmis-

sion errors (‘error correcting coding’). Phase 1 0011000 11 Uncoded on/off keying (OOK, cf. Fig. 6) in its various fla- Time vors [21] has been used in optical communications for decades because it is by far the simplest format in terms of hardware PPM implementation and integration and exhibits a good compro- 10 01 10 11 00 mise between complexity and performance. Those applications in Fig. 2 that are identified to be implementation-constrained, Intensity especially if integration and power efficiency weight heavily, Time are likely to employ uncoded OOK until capacity or sensitivity Symbol requirements dictate the use of more sophisticated formats or Figure 6. Waveforms associated with some optical modulation formats. computationally intensive error correcting coding. For sensitivity-dominated applications, in particular for space-based laser communications, binary phase shift keying (PSK, cf. Fig. 6) was studied intensively and set several sen- 10 Capacity- 256 sitivity records [22,23,24]. Further sensitivity improvements Constrained QAM 64 128 PSK can be obtained at the expense of modulation bandwidth, ei- 64 16 [38] ther by M-ary orthogonal modulation or by coding. 16 32 Orthogonal modulation formats employ M . 2 orthogonal [37] 8 [31] Shannon signal dimensions, such as M non-overlapping time slots per 4 [30] symbol duration ( pulse position modulation, PPM, cf. Fig. 6 for [29] 5 1 2 M 4) [8,14,25] or M orthogonal frequencies (M-ary frequency- OOK shift keying, FSK) [14]. In PPM, an optical pulse is transmitted 4 in one out of M slots per symbol. The occupied slot position de- PPM [36] notes the bit combination conveyed by the symbol. Both PPM 8 [23] Spectral Efficiency [b/s/Hz] and FSK expand the signal bandwidth by M/log2M compared 16 to OOK. For example, using 64-PPM, sensitivity is improved by 7.5 dB at a bit error ratio (BER) of 10–16 at the expense of a 32 Sensitivity- 256 Constrained 10-fold increase in modulation bandwidth [15]. 0.1 64 [35] With error correcting coding (‘forward error control’, FEC), 0 510152025 redundancy is introduced at the transmitter and is used to correct Required Signal-to-Noise Ratio Eb/N0 [dB] for detection errors at the receiver [26]. Typical FECs for terrestrial fiber-optic systems today operate at up to 40 Gb/s with 7% overhead and are able to correct a channel BER of of 2 3 10–3 to Figure 7. Trade-off between spectral efficiency (per polarization) and 10–16, yielding a sensitivity improvement of ~9 dB at a mere 7% sensitivity of various modulation formats limited by AWGN. Modu- bandwidth expansion. FECs with more than 11 dB of coding lation formats (bright: theoretical limits; faint: experimental results) are reported for a 7% overhead code at a pre-FEC BER of 2 3 10–3. gain at BER 5 10–16 and at a 25% bandwidth overhead have (Squares: PPM; triangles: PSK; circles: QAM; diamonds: OOK.) been implemented at 10 Gb/s [26]. These high sensitivity gains achieved by FEC at a low bandwidth expansion in comparison with orthogonal modulation come at the expense of a signifi- ~25%) is used to improve sensitivity. At currently investigated cant increase in implementation complexity for FEC processing. 100-Gb/s single-channel rates, quadrature phase shift keying Through the combination of modulation and coding, sensitivi- (QPSK) [28,29], 8-PSK [30], and 16-QAM [31] have been ties of 1 photon/bit have been reported using PPM [27]. reported, both on a single carrier and using CoWDM [32]. In contrast, capacity-constrained systems employ modula- Figure 7 visualizes the trade-off between sensitivity and tion formats that avoid an increase in modulation bandwidth spectral efficiency for the linear additive white Gaussian noise to allow for dense WDM channel packing (high spectral effi- (AWGN) channel4 [15]. The ultimate limit is given by Shannon’s ciency). Narrow modulation spectra are accomplished by stick- ing to the two-dimensional quadrature signal space, i.e., by us- 4 ing multiple levels of real and imaginary parts (or magnitude Different limits are obtained for other channels, for example for the shot noise limited case. While the AWGN channel is the most relevant for optically and phase) of the complex optical field, as shown by the three amplified transmission systems [33], free-space systems can be shot-noise examples in Fig. 3. In addition, low-overhead FEC (~7% to limited [25,34].

February 2009 IEEE LEOS NEWSLETTER 7 capacity. The lower portion of the figure belongs to the realm of sensitivity-constrained systems while the upper portion applies 100 to capacity-constrained systems. The theoretically achievable sensitivity for four classes of modulation formats (OOK, PSK, 10 QAM, PPM) are also shown, assuming the above mentioned 7% Tb/s overhead FEC (2 3 1023 pre-FEC BER). The performance of 1 some recent experimental results is captured by the fainter col- System Capacity ored symbols. It is evident that hardware implementation dif- ficulties prevent the formats from performing at their theoretical 100 Multi-Channel WDM Channels limits, both in terms of sensitivity and spectral efficiency. Single Channel (ETDM) Gb/s 10 WDM system evolution 1986 1990 1994 1998 2002 2006 2010 Fiber-optic transport systems are the most capacity-constrained 10 of all optical communication systems. To assess technological progress at the forefront of transmission capacity, Fig. 8 com- 1 piles research experiments reported at the Optical Fiber Com- munication Conferences (OFC) and the European Conferences on Optical Communications (ECOC). The green data points [b/s/Hz] 0.1 Spectral Efficiency

show the experimentally achieved bit rates of electronically Spectral Efficiency time-division multiplexed (ETDM) single-channel systems, 0.01 which reflect the historic growth rate of the speed of semiconductor electronics. By 2005/2006, ETDM bit rates had Figure 8. Progress in fiber-optic transmission capacities, as report- reached 100 Gb/s [39,40]. ed at post-deadline sessions of ECOC and OFC. (Green: Single- By the mid 1990s, the erbium-doped fiber amplifier channel ETDM rates; red: WDM aggregate capacities on a single (EDFA) had made WDM highly attractive because it could fiber; yellow: spectral efficiency.) simultaneously amplify many WDM channels. This allowed the capacity of fiber-optic communication systems to scale in constellation points per modulation symbol6. Recent studies the wavelength domain by two orders of magnitude compared on the fundamental capacity limits of optical transmission to single-channel systems, as indicated by the red data points. systems over standard single-mode fiber predict a maximum Up until ~2000, achieving a closer WDM channel spacing capacity of about 11 b/s/Hz over 2000 km [33,43], assuming was a matter of improving the stability of lasers and of build- that PDM doubles capacity compared to the reported single- ing highly frequency selective optical filters; pre-2000, the polarization case. increase in spectral efficiency, represented by the yellow data The experimentally demonstrated record for the aggregate points in Fig. 8, was therefore due to improvements in device capacity over a single optical fiber is currently at 25.6 Tb/s at technologies. a spectral efficiency of 3.2 b/s/Hz [42]. As evident from the When 40-Gb/s systems started to enter optical network- red data points in Fig. 8, reported capacities have noticeably ing at the turn of the millennium, optical modulation for- started to saturate over the last few years. With continuously mats [21,41] and coding5 [26] became very important, first increasing spectral efficiencies, this can be attributed, at least to improve sensitivity so that the reach of 40-Gb/s systems in part, to the slower growth rate of single-channel ETDM would not fall too short of that of legacy 10-Gb/s systems. bit rates, which necessitates a large increase in the number of With the simultaneous development of stable 100-GHz and WDM channels to achieve record capacities and makes such 50-GHz spaced optics, the modulated optical signal spectra experiments both time consuming and expensive. For example, quickly approached the bandwidth allocated to a single WDM the above mentioned 25.6-Tb/s experiment [42] used a total of channel, which took the increase of spectral efficiency from 320 ETDM channels (2 optical amplification bands, 80 wave- a device design level to a communications engineering level, lengths per band, and 2 polarizations per wavelength, modu- and made spectrally efficient modulation important, as it had lated at 80 Gb/s each). traditionally been the case in electronic and RF communication All the above data indicate that WDM is still scaling in systems. Using advanced communication techniques such as spectral efficiency and capacity at present but will likely reach coherent detection (presently still with off-line signal process- fundamental as well as practical limits in the near future. There- ing instead of real-time bit error counting), PDM, OFDM, and fore, new approaches have to be explored in order to continue pulse shaping, spectral efficiencies have continued to increase the scaling of capacity-constrained systems. Such approaches at multi-Gb/s rates, with today’s records being at 4.2 b/s/Hz at could include the use of lower nonlinearity or lower-loss opti- 100 Gb/s [30, 31], 5.6 b/s/Hz at 50 Gb/s [37], and 9.3 b/s/Hz cal transmission fiber [43], transmission over extended wave- at 14 Gb/s [38]. Further scaling of spectral efficiency becomes length ranges, or even the use of multi-core or multi-mode increasingly more difficult, requiring expo nentially more optical fiber [44].

6 Transporting k bits of information per symbol (and hence per unit bandwidth 5 In submarine systems, coding was introduced well before 2000 [7,26]. in quadrature space) requires 2k modulation symbols.

8 IEEE LEOS NEWSLETTER February 2009 Conclusions 8. Stephen A. Townes, Bemard L. Edwards, Abhijit Biswas, The success of digital information processing over the last cen- David R. Bold, Roy S. Bondurant, Don Boroson, Jamie tury has triggered the demand to transport massive amounts W. Bumside, David O. Caplan, Alan E. DeCew, Ramon of digital information, ranging from on-chip data buses all DePaula, Richard J. Fitzgerald, Farzana I. Khatri, Alexander the way to inter-planetary distances. Optical communication K. McIntosh, Daniel V. Murphy, Ben A. Parvin, Alen systems have been replacing electronic and RF techniques D. Pillsbury, William T. Roberts, Joseph J. Scozzafava, starting at the most demanding capacity-constrained and Jayant Sharma, Malcolm Wright, “The Mars Laser com sensitivity-constrained applications and are steadily progressing munication demonstration,” in Proc. Conf. Aerospace, 2004, towards more implementation-constrained shorter-reach systems pp. 1180–1195. that require dense integration, low power consumption, and 9. R. E. Wagner, “Fiber-based broadband access technology low cost. and deployment,” in Optical Fiber Telecommunications V, Modulation and multiplexing techniques are key de- vol. B, I. P. Kaminov, T. Li, and A. E. Willner, Eds. New sign elements of sensitivity-constrained and capacity- York: Academic, pp. 401–436, 2008. constrained systems, used to harvest the bandwidth ad- 10. R. E. Wagner, “Opportunities in telecommunications vantages that optical technologies fundamentally offer. networks,” in Proc. Optoelectronics Communications Conf. Spectrally efficient modulation will stay a key area of (OECC), 2005, Paper 5B1-1. research for capacity-constrained systems. As WDM ca- 11. S. K. Korotky, “Network global expectation model: A sta- pacities over conventional fibers are approaching their tistical formalism for quickly quantifying network needs fundamental limits, breakthroughs in fiber design and in and costs,” J. Lightwave Technol., vol. 22, no. 3, pp. 703– complementary multiplexing techniques are expected to 722, 2004. further scale capacity. 12. A. Adamiecki, M. Duelk, and J. H. Sinsky, “25 Gbit/s electrical duobinary transmission over FR-4 backplanes,” Acknowledgment Electron. Lett., vol. 41, no. 14, pp. 826–827, 2005. The author is grateful for discussions with many colleagues 13. P.J. Winzer and R.-J. Essiambre, “Advanced optical modu- in the optical communications community, including R.-J. lation formats,” in Optical Fiber Telecommunications V, vol. B, Essiambre, A. Gnauck, G. Raybon, C. Doerr, H. Kogelnik, I. P. Kaminov, T. Li, and A. E. Willner, Eds. Academic, A. Chraplyvy, R. Tkach, J. Foschini, G. Kramer, A. Leven, pp. 23–94, 2008. F. Fidler, T. Kawanishi, M. Nakazawa, D. Caplan, P. Pepeljugoski, Y. Vlasov, S. Jansen, S. Savory, and many others. 14. D. O. Caplan, “Laser communication transmitter and receiver design”, in Free-Space Laser Communications: Prin- ciples and Advances, A. Majumdar and J. Ricklin, Eds. New References York: Springer-Verlag, pp. 225–362, 2007. 1. C. E. Shannon, “A mathematical theory of communication,” Bell Syst. Tech. J., vol. 27, no. 3, pp. 379–423, 1948. 15. J. G. Proakis, Digital Communications. New York: McGraw- Hill, 2001. 2. G. E. Moore, “Cramming more components into integrated circuits,” Electron. Mag., vol. 38, no. 8, 1965. 16. K. Kikuchi, “Coherent optical communication systems,” in Optical Fiber Telecommunications V, vol. B, I. P. Kaminov, 3. Y. Vlasov, “Silicon photonics for next generation comput- T. Li, and A. E. Willner, Eds. New York: Academic, pp. ing systems,” in Proc. 34th European Conf. Exhibition Optical 95–130, 2008. Communication (ECOC), 2008, Paper Tu.1.A.1. [Online]. Available: http://www.research.ibm.com/photonics 17. S. L. Jansen, “Optical OFDM, a hype or is it for real?” in Proc. European Conf. Optical Communication (ECOC), 2008, 4. J. A. Kash, F. E. Doany, C. L. Schow, R. Budd, C. Baks, Paper Mo.3.E.3. D. M. Kuchta, P. Pepeljugoski, L. Schares, R. Dangel, F. Horst, B. J. Offrein, C. Tsang, N. Ruiz, C. Patel, R. Hor- 18. H. Sanjoh, E. Yamada, and Y. Yoshikuni, “Optical orthog- ton, F. Libsch, J. U. Knickerbocker, “Terabus: Chip-to- onal frequency division multiplexing using frequency/ chip board level optical data buses,” in Proc. 21st Annu. time domain filtering for high spectral efficiency up to 1 Meeting IEEE Lasers Electro-Optics Soc. (LEOS), 2008, Paper bit/s/Hz,” in Proc. Optical Fiber Communication Conf. (OFC), WM1, pp. 515–516. 2002, Paper ThD1. 5. A. F. Benner, M. Ignatowski, J. A. Kash, D. M. Kuchta, 19. A. D. Ellis, F. C. G. Gunning, B. Cuenot, T. C. Healy, and and M. B. Ritter, “Exploitation of optical interconnects in E. 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February 2009 IEEE LEOS NEWSLETTER 9 22. B. Wandernoth, “20 photon/bit 565 Mbit/s PSK homo- OFDM transmission over 3,600 km of SMF with 19-ps dyne receiver using synchronisation bits,” Electron. Lett., average PMD,” in Proc. European Conf. Exhibition Optical vol. 28, no. 4, pp. 387–388, 1992. Communication (ECOC), 2008, Paper Th3.E.1. 23. W. Atia and R. S. Bondurant, “Demonstration of return- 33. R.-J. Essiambre, G. J. Foschini, G. Kramer, P. J. Winzer, to-zero signaling in both OOK and DPSK formats to “Capacity limits of information transport in fiber-optic improve receiver sensitivity in an optically preamplified networks,” Phys. Rev. Lett., vol. 101, no. 16, p. 163901, receiver,” in Proc. IEEE Lasers Electro-Optics Soc. (LEOS), 2008. 1999, Paper TuM3. 34. J. P. Gordon, “Quantum effects in communication sys- 24. M. L. Stevens et al., “Optical homodyne PSK demon- tems,” Proc. IRE, vol. 50, pp. 1898–1908, 1962. stration of 1.5 photons per bit at 156 Mbps with rate-½ 35. D. O. Caplan, B. S. Robinson, R. J. Murphy, and M. L. turbo coding,” Opt. Express, vol. 16, no. 14, pp. 10412– Stevens, “Demonstration of 2.5-Gslot/s optically pream- 10420, 2008. plified M-PPM with 4 photons/bit receiver sensitivity,” in 25. D. M. Boroson, “A survey of technology-driven capacity Proc. Optical Fiber Communication Conf. (OFC), 2005, Paper limits for free-space laser communication,” Proc. SPIE, PDP32. vol. 6709, pp. 670918-1–670918-19, 2007. 36. D. O. Caplan and W. A. Atia, “A quantumlimited opti- 26. T. Mizuochi, “Next generation FEC for optical communi- cally-matched communication link,” in Proc. Optical Fiber cation,” in Proc. Optical Fiber Communication Conf. (OFC), Communication Conf. (OFC ’01), Paper MM2. 2008, Paper OTuE5. 37. H. Takahashi, A. Al Amin, S. L. Jansen, I. Morita, and H. 27. P. I. Hopman, P. W. Boettcher, L. M. Candell, J. B. Tanaka, “8x66.8-Gbit/s coherent PDM-OFDM transmis- Glettler, R. Shoup, G. Zogbi, “An end-to-end dem- sion over 640 km of SSMF at 5.6-bit/s/Hz spectral effi- onstration of a receiver array based free-space photon ciency,” in Proc. European Conf. Exhibition Optical Communi- counting communications link,” Proc. SPIE, vol. 6304, cation (ECOC), 2008, Paper Th3.E.4. p. 63040H, 2006. 38. M. Nakazawa, “Challenges to FDM-QAM coherent trans- 28. M. Daikoku, I. Morita, H. Taga, H. Tanaka, T. Kawanishi, mission with ultrahigh spectral efficiency,” in Proc. Euro- T. Sakamoto, T. Miyazaki, T. Fujita, “100 Gbit/s DQPSK pean Conf. Exhibition Optical Communication (ECOC), 2008, transmission experiment without OTDM for 100G Eth- Paper Tu.1.E.1. ernet transport,” in Proc. Optical Fiber Communication Conf. 39. P. J. Winzer, G. Raybon, and M. Duelk, “107-Gb/s Op- (OFC), 2006, Paper PDP36. tical ETDM Transmitter for 100G Ethernet Transport,” in Proc. European Conf. Exhibition Optical Communication 29. C. R. S. Fludger, T. Duthel, D. van den Borne, C. Schu- (ECOC), 2005, Paper Th4.1.1. lien, E-D. Schmidt, T. Wuth, E. de Man, G. D. Khoe, and H. de Waardt, “10 x 111 Gbit/s and 50 GHz spaced and 40. R. H. Derksen, G. Lehmann, C.-J. Weiske, C. Schubert, POLMUX-RZ-DQPSK transmission over 2375 km em- R. Ludwig, S. Ferber, C. Schmidt-Langhorst, M. Moller, ploying coherent equalisation,” in Proc. Optical Fiber Com- J. Lutz, “Integrated 100 Gbit/s ETDM receiver in a trans- munication Conf. (OFC), 2007, Paper PDP22. mission experiment over 480 km DMF,” in Proc. Optical Fiber Communication Conf. (OFC), 2006, Paper PDP37. 30. X. Zhou, J. Yu, D. Qian, T. Wang, G. Zhang, and P. D. Magill, “8 x 114 Gb/s, 25-GHz-spaced, PolMux-RZ- 41. A. H. Gnauck and P. J. Winzer, “Optical phase-shift- 8PSK transmission over 640 km of SSMF employing digi- keyed transmission,” J. Lightwave Technol., vol. 23, no. 1, tal coherent detection and EDFA-only amplification,” in pp. 115–130, 2005. Proc. Optical Fiber Communication Conf. (OFC), 2008, Paper 42. A. H. Gnauck, G. Charlet, P. Tran, P. Winzer, C. Doerr, PDP1. J. Centanni, E. Burrows, T. Kawanishi, T. Sakamoto, and 31. P. J. Winzer and A. H. Gnauck, “112-Gb/s polarization- K. Higuma, “25.6-Tb/s C+L-band transmission of polar- multiplexed 16-QAM on a 25-GHz WDM grid,” in Proc. ization-multiplexed RZDQPSK signals,” in Proc. Optical European Conf. Exhibition Optical Communication (ECOC), Fiber Communication Conf. (OFC), 2007, Paper PDP19. 2008, Paper Th3.E.5. 43. R.-J. Essiambre, “Capacity limits of fiber-optic communi- 32. A. Sano, E. Yamada, H. Masuda, E. Yamazaki, T. Ko- cation systems,” in Proc. Optical Fiber Communication Conf. bayashi, E. Yoshida, Y. Miyamoto, S. Matsuoka, R. Kudo, (OFC), 2009. K. Ishihara, Y. Takatori, M. Mizoguchi, K. Okada, K. 44. H. R. Stuart, “Dispersive multiplexing in multimode Hagimoto, H. Yamazaki, S. Kamei, and H. Ishii, “13.4- optical fiber,” Science, vol. 289, no. 5477, pp. 281–283, Tb/s (134 x 111-Gb/s/ch) no-guard-interval coherent 2000.

10 IEEE LEOS NEWSLETTER February 2009 Research Highlights Electronic Signal Processing for Fiber-Optic Communications John Cartledge1, David Krause2, Kim Roberts2, Charles Laperle2, Doug McGhan2, Han Sun2, Kuang-Tsan Wu2, Maurice O’Sullivan2, and Ying Jiang1

1: QUEEN’S UNIVERSITY, KINGSTON, ON CANADA Drive Amplifier 2: NORTEL NETWORKS, OTTAWA, ON CANADA DAC Input Optical Output DSP Laser Abstract: The powerful capabilities of electronic digital signal Signal Modulator Optical Signal processing in the transmitter and receiver are reviewed for high DAC bit rate fiber-optic communications. Drive Amplifier

1. Introduction Figure 1. Pre-compensating transmitter. DSP: digital signal Recent developments in electronic digital signal processing processor. DAC: digital-to-analog converter. technology have led to a new paradigm in fiber-optic communications. The realization of suitable high-speed digital- to-analog converters (DACs), analog-to-digital converters Drive Signal (ADCs), and digital signal processors has allowed advanced CW Optical Modulated Optical signal processing to offer substantial improvements in system Input Output Signal performance. The signal processing can be performed in the Signal transmitter and/or the receiver. In the transmitter, the synthe- Drive Signal sis of the appropriate drive signals for an optical modulator permits the generation of modulated optical signals with un- Drive Signal precedented control of the time-varying amplitude and phase. In the receiver, coherent detection preserves both the ampli- CW Optical Modulated Optical Input tude and phase of the received optical signal in the detected ° Output Signal Signal 90 signal, thereby allowing for the effective mitigation of transmission impairments and the implementation of key receiver Drive Signal functions. The signal processing can be made adaptive to accommodate a time varying channel. Figure 2. Dual-drive (top) and quadrature (bottom) Mach-Zehnder optical modulators. In this paper, we describe four applications of electronic signal processing: pre-compensation for chromatic dispersion portion of the complex plane is determined by the two bias and self-phase modulation, pre-compensation for optical filter- and modulation voltages applied to modulator. The benefit of ing, the generation of advanced modulation formats, and post- the increased complexity of a quadrature modulator is that this compensation with coherent detection. limitation is removed. The electrical drive signals in Fig. 1 for the modulator are obtained from the digital signal processor, 2. Pre-compensation for Chromatic followed by digital-to-analog conversion and amplification. Dispersion and Self-Phase Modulation The chromatic dispersion of an optical fiber acts a linear A pre-compensating transmitter is shown in Fig. 1. A tunable operation on the electric field of the transmitted optical signal laser is used as a continuous-wave (CW) source and a Mach- and its effects can be undone by linear filtering. The number Zehnder modulator is used to modulate the optical field. Two of taps for a digital filter increases with the maximum amount types of modulators are commonly used: a dual-drive Mach- of chromatic dispersion to be compensated. Transmitter-based Zehnder modulator and a quadrature Mach-Zehnder modu- electronic pre-compensation for fiber chromatic dispersion was lator. The latter consists of two single-drive Mach-Zehnder initially proposed in [1] and [2]. modulators within a Mach-Zehnder interferometer. A fixed The first experimental results were obtained using a proof- 90o phase shift in one arm of the interferometer allows for of-principle implementation of a 20 GSa/s 4-bit DAC [3]. A independent modulation of the in-phase and quadrature com- 152-tap finite-impulse response (FIR) filter was used to filter ponents of the optical field. The modulators are illustrated the transmit data with the complex conjugate of the fiber trans- schematically in Fig. 2. For a dual-drive Mach-Zehnder modu- fer function before modulating the transmitter. The calculated lator, arbitrary combinations of amplitude and phase for the pre-compensated analog drive waveforms were also corrected optical field are difficult to obtain in practice; the accessible for the frequency responses of the DACs, drive amplifiers, and

February 2009 IEEE LEOS NEWSLETTER 11 to 10220. Self-phase modulation (SPM), a non- 0 km 320 km Without Pre- linear effect in optical fibers, prevents a BER Compensation below the FEC threshold from being obtained for 5120 km of fiber and an average transmitted optical power of 25 dBm. The linear compensation results can be improved further by applying nonlinear pre-compensation for SPM [4]. Fig. 4 also shows results for a transmitted optical power of 25 dBm with SPM compensation. 1,600 km 3,200 km 5,120 km The required OSNR is improved by 0.75 dB, and hence the system margin is increased by 2.75 dB, compared to linear compensation only with a transmitted optical power of 27 dBm. Subsequently, two DACs and the digital signal processing circuits were implemented in a 2 million gate, application specific inte- Figure 3. Eye diagrams at the receiver for 10.7 Gb/s RZ-DPSK transmission over 0, grated circuit (ASIC) fabricated in 130 nm 1600, 3200, and 5120 km of single-mode fiber with pre-compensation. The eye diagram BiCMOS technology. The ASIC is capable of for 320 km without pre-compensation is shown for comparison. Timebase is 20 ps/div. 6 trillion integer operations per second. The setting of the pre-compensation can be based on estimates or knowledge of the fiber properties, or on auto- 10–1 matic discovery and optimization. Without SPM Compensation (–7 dBm) 3. Pre-compensation for Optical Filtering With SPM Compensation (–5 dBm) In spectrally efficient optical networks, signals passing through

–2 multiple reconfigurable optical add-drop multiplexers can be 10 distorted by the bandwidth narrowing that results from the cas- FEC Limit caded optical filtering. While pre-compensation for chromatic dispersion addresses the effects of phase distortion, here the emphasis is on the effects of amplitude distortion [5]. An opti- Bit Error Ratio 10–3 cal spectrum analyzer was used as a narrow bandpass filter to represent the overall response of concatenated filters. The filter had 23 dB and 220 dB bandwidths of 9.1 GHz and 20 GHz, respectively. The phase response of the filter was linear over the 230 dB bandwidth. 10–4 8 9 10 11 12 13 14 15 16 17 For 10 Gb/s non-return-to-zero on-off-keyed (NRZ-OOK) Optical Signal-to-Noise Ratio (dB) modulation, eye diagrams are shown in Fig. 5 for the transmitted and filtered optical signals, without and with pre-compensation. Figure 4. Dependence of the BER on the OSNR (0.1 nm noise band- The transmitted signal without pre-compensation used an ideal width) with and without SPM compensation for 5120 km transmis- raised-cosine pulse shape with a roll-off factor of 0.7 and a dual- sion of a 10 Gb/s RZ-DPSK signal. drive Mach-Zehnder modulator. Qualitatively the eye diagram opens considerably when pre-compensation is used. quadrature Mach-Zehnder modulator. The pre-compensated The corresponding dependence of the BER on the OSNR of waveforms for a 21121 pseudo-random bit sequence (PRBS) the received signal is shown in Fig. 6 (results with solid line). were stored in programmable pulse pattern generators. The intersymbol interference due to the narrow filtering causes Fig. 3 shows the measured eye diagrams for the transmission a 5.8 dB OSNR penalty (at BER 5 1 3 1029). With pre-com- of a 10.7 Gb/s return-to-zero differential phase-shift-keyed (RZ- pensation, the OSNR penalty is reduced to 1.8 dB. For a dual- DPSK) signal over single-mode fiber (G.652) [3]. Eye diagrams drive Mach-Zehnder modulator, the extent of the improvement are shown for the back-to-back case, and after 1600, 3200, and is limited by the requirement that the pre-compensated optical 5120 km of fiber. The average launch power was 27 dBm. No op- field lie within the accessible portion of the complex plane. The tical dispersion compensation was used. For comparison, the eye pre-compensation can be improved by using a quadrature mod- diagram for 320 km without pre-compensation is also shown. ulator. This is also illustrated in Fig. 6 (results with dashed line); The dependence of the bit error ratio (BER) on the opti- the OSNR penalty with pre-compensation is only 0.9 dB. cal signal-to-noise ratio (OSNR) of the received signal is shown in Fig. 4 for an average transmitted optical power of 27 dBm 4. Modulation Formats and a fiber length of 5120 km. Also included in the graph is a By using high-speed digital signal processing and DACs, modu- typical forward-error-correction (FEC) coding threshold at lation formats that require multi-level modulator drive voltages BER 5 3.84 3 1023; FEC decoding will correct this raw BER can be generated. For example, 20 Gb/s differential quadrature

12 IEEE LEOS NEWSLETTER February 2009 Transmitted Without Pre- Filtered Without Pre- 1.0 Compensation Compensation

(0,1) (1,1) 0.5

Transmitted With Pre- Filtered With Pre- 0.0 Compensation Compensation

Imaginary Part (V/m) –0.5 (0,0) (1,0)

–1.0 Figure 5. Eye diagrams at the transmitter and after the optical fil- –1.0 –0.5 0.0 0.5 1.0 ter, without and with pre-compensation. Timebase is 30 ps/div. Real Part (V/m)

Figure 7. Ideal output of the dual-drive Mach-Zehnder modulator shown 10–4 on the complex plane. The accessible portion of the complex plane for a dual-drive Mach-Zehnder modulator biased at extinction and peak-to- 10–5 peak RF drive voltages of Vp is shown by the gray shaded region.

10–6

10–7

10–8 Bit Error Ratio 10–9

–10 10 Figure 8. Left: Output optical power of the transmitter. Right: Eye diagram of the U channel after the delay interferometer. Timebase 10–11 14 16 18 20 22 24 26 28 is 25 ps/div. Optical Signal-to-Noise Ratio (dB) For 20 GSa/s DACs, there are two samples per symbol for Back-to-Back the modulator drive signals. The first sample corresponds to Without Pre-Compensation the optical field associated with the symbol. The second sample With Pre-Compensation defines the signal trajectory in accordance with the constraint indicated in Fig. 7. To select the value for the second sample, Figure 6. Dependence of the BER on the OSNR (0.1 nm noise the next symbol was examined to determine the necessary tran- bandwidth) for a 10 Gb/s NRZ-OOK signal: back-to-back without sition. For a repeated symbol, the second sample was a repeat filtering, filtering without pre-compensation, and filtering with of the first. For horizontal and diagonal transitions (i.e., (0,1) pre-compensation. Solid line: dual-drive Mach-Zehnder modulator. Dashed line: quadrature Mach-Zehnder modulator. to (1,1) or (0,0) to (1,1)), the second sample corresponded to the origin. For vertical transitions (i.e., (1,0) to (1,1)), the second sample corresponded to 60.5 1 j0. For this demonstra- phase-shift keying (DQPSK) modulation can be achieved with tion, the required voltages were calculated at each sample time a single dual-drive Mach-Zehnder modulator, rather than a (pre-coding, look-up table and pre-emphasis), stored in the quadrature modulator which is conventionally used for DQPSK arbitrary electrical pattern generator of the pre-compensation [6]. The use of a single dual-drive Mach-Zehnder modulator to ASIC, and then applied to the modulator through the DACs generate DQPSK was introduced theoretically in [7]. and drive amplifiers. The accessible region of the complex plane is shown by the Optical waveforms were generated with two different 214 gray shaded region in Fig. 7 for a dual-drive Mach-Zehnder mod- deBruijn bit patterns for the in-phase and quadrature channels ulator biased at extinction and peak-to-peak RF drive voltages (denoted U and V). To visualize the optical signal, a simulation p of Vp (voltage that changes the phase by ). The constellation result with ideal drive voltages for 128 symbols is shown in points 60.5 6 j0.5 cause a 3 dB loss in the peak output power Fig. 7. The constellation points are clearly visible. With 20 GSa/s which could be avoided by using drive voltages of 1.5 Vp. sampling, the trajectories between constellation points tend to

February 2009 IEEE LEOS NEWSLETTER 13 a powerful approach for mitigating transmission impairments 10–4 and implementing required functions in a fiber-optic receiver U Channel [8]. As an example, coherent detection of dual-polarization 10–5 V Channel QPSK is shown in Fig. 10. By transmitting two independent QPSK signals on orthogonal states-of-polarization, the symbol rate is 10 Gsymbol/s for a data rate of 40 Gb/s. The received –6 10 signal is passed through a polarization beam splitter and de- composed into two orthogonal signals. Each orthogonal signal 10–7 is applied to an optical hybrid together with a local oscillator (LO) signal that is provisioned to select the WDM chan-

Bit Error Ratio Bit 10–8 nel. The frequency of the LO laser is controlled to be within a few hundred MHz of the carrier frequency for the received signal. The four resulting polarization and phase orthogonal –9 10 signals are detected by individual photodiodes, amplified, filtered and then digitized using four 20 GSa/s ADCs with 10–10 6-bit resolution. The ADCs and the overall receiver circuits –35 –34 –33 –32 have a net 3 dB bandwidth of 6 GHz. Clock recovery, carrier Received Optical Power (dBm) recovery, polarization tracking, polarization mode dispersion Figure 9. Dependence of the BER on the received optical power for (PMD) tracking, and dispersion compensation are performed the U and V channels. digitally, requiring 12 trillion integer operations per second. The post-compensation adapts to time variations in the chan- take arcs. The digital-to-analog conversion causes the RF drive nel (e.g., temperature-induced changes in the chromatic dis-

voltages to occasionally exceed Vp, in which case the optical persion). The four ADCs, digital signal processing circuits, field extends outside the gray shaded region. and a supervisory processor have been implemented in a cus- The optical power at the output of the transmitter is shown tom mixed-signal 20 million gate ASIC using 90 nm CMOS in Fig. 8. The dips in the eye diagram indicate where transi- technology (Fig. 11). tions occur through the origin. Following the delayed inter- To test the tolerance to dispersion and PMD, a 46.008 Gb/s ferometer in the receiver, the eye diagram for the U channel (11.502 Gbaud) signal was transmitted through a link consist- at a BER of 131029 is also shown in Fig. 8. Since horizontal ing of 900 km of single mode fiber (G.652) and PMD emula- transitions pass through the origin, the upper rail is missing. tion. The link did not have any optical dispersion compensation. The non-ideal responses of the DACs and drive amplifiers lead The bit rate includes 7% overhead for FEC coding and a 23121 to a pattern dependence in the multi-level drive voltage wave- pseudo-random bit sequence was used in the transmitter. White forms. This causes the broad rails in the eye diagram, which are amplified spontaneous emission noise was added before the receiver consistent with the arc-like signal trajectories shown in Fig. 7. to vary the OSNR. The net dispersion of about 15000 ps/nm The dependence of the measured BER on the received optical (900 km 3 16.7 ps/km/nm) was entirely compensated in the re- power is shown in Fig. 9. A receiver sensitivity of 232.5 dBm ceiver ASIC. In order to assess the purely linear performance of at a BER of 131029 was achieved with the U and V channels the coherent receiver, the launch power was kept below 26 dBm differing by only 0.25 dB. after each amplifier for a single optical channel. Fig. 12 shows the measured BER of this link, with add- 5. Coherent Detection ed first-order PMD (peak differential group delay) of 0 and and Post-compensation 50 ps. The fiber and amplifier PMD is negligible. The FEC The combination of coherent (intradyne) detection, analog- threshold at BER 5 3.84 3 1023 is also shown. The re- to-digital conversion, and digital signal processing provides quired OSNR is 10.8 dB (0.1 nm noise bandwidth) at the FEC threshold. For comparison, results are also shown for the theoretical and measured back-to-back performance. The receiver is I Data Input Signal PBS PD ADC x robust to 50 ps of rapidly varying first- 90° order PMD and 15,000 ps/nm of dispersion Hybrid PD ADC Qx Data as the three measured curves are the same, DSP within experimental error. Recently, a rigorous assessment of the transmission perfor- PD ADC Iy Data 90° mance of a 46 Gb/s dual-polarization QPSK Local Hybrid PMS transceiver has been performed [9]. Oscillator PD ADC Qy Data 6. Conclusion Figure 10. Block diagram of a dual-polarization QPSK receiver. PBS: polarization Advanced electronic signal processing beam splitter. PMS: polarization maintaining splitter. PD: photodiode. ADC: analog- for fiber-optic transmitters and receivers to-digital converter. DSP: digital signal processor. has enabled dramatic improvements in

14 IEEE LEOS NEWSLETTER February 2009 10–2

FEC Limit

10–3 Bit Error Ratio

10–4 8 9 10 11 12 13 14 Optical Signal-to-Noise Ratio (dB)

CD = 15,000 ps/nm, DGD = 50 ps CD = 15,000 ps/nm, DGD = 0 ps CD = 0 ps/nm, DGD = 0 ps Theoretical Back-to-Back

Figure 11. CMOS receiver ASIC with four ADCs and digital signal Figure 12. Measured BER for single channel transmission in a processor. 900 km link (chromatic dispersion (CD) of 15,000 ps/nm), with and without PMD (differential group delay (DGD) of 50 ps). For comparison, theoretical and measured results for the back-to-back performance are also shown. transmission performance and substantially enriched the field 4. K. Roberts, C. Li, L. Strawczynski, M. O’Sullivan, and I. of fiber- optic communications. To illustrate these attributes, Hardcastle, “Electronic precompensation of optical non- we have briefly described four applications: pre-compensation linearity,” IEEE Photon. Technol. Lett., vol. 18, no. 2, pp. for chromatic dispersion and self-phase modulation, pre- 403–405, 2006. compensation for optical filtering, the generation of advanced 5. D. J. Krause, Y. Jiang, J. C. Cartledge, and K. Roberts, modulation formats, and post-compensation with coherent “Pre-compensation for narrow optical filtering of 10 Gb/s detection. intensity modulated signals,” IEEE Photon. Technol. Lett., vol. 20, no. 9, pp. 706–708, 2008. References 6. D. J. Krause, J. C. Cartledge, and K. Roberts, “Demonstra- 1. R. I. Killey, P. M. Watts, V. Mikhailov, M. Glick, and tion of 20-Gb/s DQPSK with a single dual-drive Mach- P. Bayvel, “Electronic dispersion compensation by signal Zehnder modulator,” IEEE Photon. Technol. Lett., vol. 20, predistortion using digital signal processing and a dual- no. 16, pp. 1363–1365, 2008. drive Mach-Zehnder modulator,” IEEE Photon. Technol. Lett., 7. K.-P. Ho and H.-W. Cuei, “Generation of arbitrary quadra- vol. 17, no. 3, pp. 714–716, 2005. ture signals using one dual-drive modulator,” J. Lightwave 2. J. McNicol, M. O’Sullivan, K. Roberts, A. Comeau, Technol., vol. 23, no. 2, pp. 764–770, 2005. D. McGhan, and L. Strawczynski, “Electrical domain 8. H. Sun, K.-T. Wu, and K. Roberts, “Real-time measure- compensation of optical dispersion,” in Proc. Conf. ments of a 40 Gb/s coherent system,” Optics Express, vol. 16, Optical Fiber Commun., Anaheim, CA, 2005, Paper no. 2, pp. 873–879, 2008. OThJ3. 9. L. E. Nelson, S. L. Woodward, S. Foo, X. Zhou, M. D. 3. D. McGhan, C. Laperle, A. Savchenko, C. Li, G. Mak, and Feuer, D. Hanson, D. McGhan, H. Sun, M. Moyer, M. M. O’Sullivan, “5120-km RZ-DPSK transmission over O’Sullivan, and P. D. Magill, “Performance of a 46-Gbps G.652 fiber at 10 Gb/s without optical dispersion com- dual-polarization QPSK transceiver with real-time co- pensation,” IEEE Photon. Technol. Lett., vol. 18, no. 2, pp. herent equalization over high PMD fiber,” J. Lightwave 400–402, 2006. Technol., submitted for publication.

February 2009 IEEE LEOS NEWSLETTER 15 Research Highlights Radio over Fiber Distributed Antenna Networks Michael J. Crisp, Student Member, IEEE, Sithamparanathan Sabesan, Student Member, IEEE, Richard V. Penty, Senior Member, IEEE and Ian H. White, Fellow, IEEE

of it carried out in collaboration with Professor Alwyn Seeds ELECTRICAL ENGINEERING DIVISION, UNIVERSITY OF CAMBRIDGE, CB3 0FA, CAMBRIDGE, U.K of University College London, have been commercialized by (E-MAIL: [email protected]) Zinwave Ltd [1]. The optical DAS typically consists of a hub unit in the equipment room, which in the downlink combines the radio Introduction frequency (RF) signals from the base stations and performs The rapid evolution and convergence of wireless technologies electrical-to-optical conversion, normally by applying the RF and services, coupled with the emerging trend of frequency mi- signal as a modulation current directly to the laser bias. The gration of existing services, is leading to in-building wireless optical signal is then carried over optical fiber to the antenna service provision becoming a complex battleground for both unit where optical-to-electrical conversion is performed by a businesses and operators alike. Such companies now need the photodiode before the RF signal is amplified and transmitted agility and infrastructure to quickly and cost-effectively deploy from an antenna. In the uplink (mobile station to base station), new wireless services and upgrade applications on demand in the process is identical but reversed. order to retain consumer loyalty, generate new revenues and A key aspect to the links that are now being commercial- enable greater productivity from employees. ized by Zinwave is their broadband nature over the 300 MHz At the same time, to meet the increased demand for band- to 2.7 GHz frequency range. Previously, performance over the width, the carrier frequency of wireless services has been forced 1 GHz to 20 GHz range was been demonstrated by an un- higher, and spectral efficiency has been increased, resulting cooled laser operating over both single and multimode opti- in reduced system tolerance to the poor radio environment cal fiber [2]. Since the optical link is essentially transparent to within buildings. In order to overcome the problem of poor the RF signal, and is agnostic to the modulation formats and propagation, antennas must be distributed around buildings, reducing the effect of free-space losses and multipath effects. Traditionally this is achieved either by distributing base stations around the building (as is common in wireless local area network (LAN) installations) or by centrally locating all the radio hardware at a single location and using some form of distributed antenna system (DAS). In the past, such systems have been implemented using coaxial cables and leaky feeder antennas, even though the limited bandwidth and high attenuation of coax in the gigahertz frequency range may require a separate network to be used for each wireless service. A traditional in- building wireless installation is shown in Figure 1. Here a leaky feeder DAS is providing 3G coverage and a distributed wireless LAN service. In practice, large buildings would have many more networks. As wireless services migrate to higher carrier frequencies this approach becomes less commercially and tech- nically attractive as the cost-performance tradeoff worsens. The lower losses and wide bandwidth offered by optical fiber enable radio over fiber based distributed antenna systems to carry all required services on a single network as shown in Figure 2. Research at Cambridge has sought to develop low- cost DAS units that can operate over any of the common transmission media − single mode optical fiber, multimode optical 3G LAN fiber or coax cable − and allow multiple services to be transmitted simultaneously. In order for low-cost operation to be achieved, work has focused on the use of uncooled laser diodes Figure 1. A traditional wireless installation with distributed at the transmitter. Recently, the results of this work, much WLAN hardware and a separate 3G leaky feeder installation.

16 IEEE LEOS NEWSLETTER February 2009 protocols in use, an upgrade to accommodate future services only requires modification of the base station in the equipment room. By comparison, a traditional installation would require changes to the hardware throughout the building, either by changing a distributed hardware installation or by installing a new coax distribution system. Additional advantages of the optical DAS approach include enhanced security by careful control of the radio footprint and reduced power requirements at each antenna. As a result, the Zinwave DAS allows businesses and facili- ties to deploy a single, centrally managed platform to support multi-service/multi-operator wireless coverage without requiring either parallel service specific units or cabling overlays. Any number or combination of services are supported – including 2G/3G to LTE, WiFi, WiMAX, TETRA, private mobile radio, RFID and DVB-H – enabling simultaneous mobility for employees, consumers and emergency services. It also uniquely supports Time Division Duplex (TDD) services. Importantly, the system supports new and frequency migrating services without the need for disruptive and costly upgrades, additional hardware, or cable overlays. Indeed the systems incorporate a built-in Element Manage- HUB3G WLAN ment System (EMS), for centralised monitoring and configuration. A web-based interface allows the RF management Figure 2. Example building with a multi-service optical DAS features to be accessed directly and integrated into existing management systems. IEEE 802.11g signals as a test case, an EVM of less that 4% has Progression from DAS to DAN been achieved across the switch using three cascaded SOAs [5]. While DAS have the potential for reducing the maintenance This performance is well within the 5.6% limit for 54 Mbps burden by allowing centralized location of hardware and us- operation of IEEE 802.11g. ing fiber to remote the antennas, distributed antenna networks (DAN) that allow multicasting and eventually switching of Propagation Effects using an Optical DAN the same RF signal over several antennas will bring a range of The low loss offered by optical fiber allows a fiber-fed DAN other improvements. Recent research at Cambridge therefore to operate in ways not previously possible with co-axial ca- has focused on the opportunities arising from DAN. bles. For instance, the lower attenuation may give rise to long Within a DAN, multicasting may be carried out in the propagation delays along the fiber. Coupled with an ability to electrical domain through careful circuit design. However, op- transmit the signal from multiple antennas, this gives rise to tical splitting allows the full bandwidth of optical fiber to be potential multi-path effects with path differences (mainly in exploited. As a 3dB splitting loss in the optical domain results the fiber) much greater than those generally seen in conven- in a 6dB loss in the RF signal, optical amplification must be tional wireless systems. employed for large splits to overcome the losses. Cambridge Detailed experiments have however shown, that provided has demonstrated such a multicast system with up to 256 these differences in delay are kept within certain (service de- splits using semiconductor optical amplifiers (SOAs) as the pendent) limits, that a DAN can provide greatly improved gain block [3]. More recently silicon avalanche photodiodes wireless coverage compared to single antenna systems. (APDs) have been used to increase the receiver sensitivity in Figure 3 shows a comparison of the downlink IEEE 802.11g short wavelength links [4]. throughput of a single antenna system and a 3-antenna DAS The use of SOA switch matrices in RoF links can also enable using the same total output power. Detailed analysis shows radio service switching functionality, which brings the poten- that the single antenna would in this case require 15 dB tial for dynamic management of radio resources in response more power to achieve the same quality of coverage as the to demand. For example, in an airport departure gate, there 3-antenna system [6]. The increase in power requirement if a may be a large demand for bandwidth just prior to boarding, DAN is not used also increases the requirements for antenna but the gate may then remain unused for a number of hours. isolation between the up and downlinks, and dynamic range With a switched DAN, the shapes and locations of cells could requirements. Similar improvements have been demonstrat- be managed to meet this dynamic demand with a far lower ed in the uplink and with other services. Figures 3(b) and overhead of excess base-station capacity than is currently used 3(c) show a comparison of the DAN with equal fiber lenghts using conventional static approaches. We have carried out and with one AU fed by a fiber 30 m longer. It can be seen demonstrations of 32x32 RoF switches similar to those un- that this additional delay and multipath does not degrade der development for data communications applications. Using the performance.

February 2009 IEEE LEOS NEWSLETTER 17 intelligent infrastructure are likely to in- Single Antenna Downlink Throughput (Mbps) clude sensor networks in addition to com- 20 munications services. In a manner simi- 6 1919 19 16 lar to that in communications services, a 1920 19 11 barrier to the widespread introduction of 4 1918 15 15 181919 19 19 19 many sensor networks is the cost of in- 2 19 18 19 18 20 19 19 stallation and deployment, so an overlay 0 19 19 of the sensor network on the communi-

(m) 6.57.37.2 117.27.99.6 16 178.8 18 18 18 19 19 19 19 19 19 19 19 15 14 18 19 18 10 –2 cations infrastructure makes economic sense. While the various communications 19 15 11 6.4 –4 5 standards in use have broadly similar re- –6 quirements from the optical link in terms of output power, bandwidth, noise, and –8 0 –15 –10 –5 0510 linearity, sensor networks bring a new set (m) of challenges. (a) One sensing system of particular interest is passive UHF RFID. By transmit- Triple Antenna with Equal Fiber Lengths Downlink Throughput (Mbps) ting a high power carrier in the downlink, 20 RFID tags are able to operate without an 6 2020 20 11 2020 20 9.7 internal power supply greatly reducing 4 2020 19 cost. However, the required downlink 20 2020 19 19 15 2 2019 20 19 power is typically 20–30 dB greater than 20 20 20 that for short-range wireless communica- 0 20 19 10 (m) 20 20 19 19 19 19 19 20 20 20 19 19 19 19 19 19 19 19 20 19 18 19 19 20 20 19 tions services. As a result of the higher –2 output power, if RFID and communica- 14 –4 19 15 14 149.2 tions services are carried on the same opti- 5 cal network, the high power of the RFID –6 service induces nonlinear distortion in –8 the laser diode. For a typical broadband 0 –15 –10 –5 0510 DAS with a bandwidth of 300 MHz to (m) 2.7 GHz, the generated second harmonic (b) of UHF RFID in the 900 MHz band will occur at 1.8 GHz, within the bandwidth Triple Antenna with Different Fiber Lengths Downlink Throughput (Mbps) 20 of the DAS. Regulations strictly limit 6 2020 19 15 the allowed levels of such spurious emis- 1920 19 14 sions to prevent unwanted interference in 4 1918 15 1919191820 19 15 other wireless systems. Conventionally, a 2 19 19 20 20 filter would be used before the antenna to 20 19 0 19 19 reduce out of band spurious emissions to

(m) 20 19 19 19 19 19 19 19 19 1920 19 19 1917 19 18 20 19 20 19 20 19 19 20 20 10 acceptable levels. However, to maintain –2 16 the transparent broadband nature of the –4 18 15 11 DAS and allow future upgrades it is de- 5 sirable to not have to add any additional –6 hardware at the antenna unit. In order to –8 0 reduce the level of the second harmonic –15 –10 –5 0 5 10 (m) in this case, a simple electronic cancellation scheme has been developed. Using (c) this scheme a RoF link has been demonstrated to support IEEE 802.11g and Figure 3. Comparison of 802.11g Throughput in single antenna and triple antenna RFID simultaneously [7]. installations. Throughputs are given in MBps of TCP/IP traffic, the locations of the Besides allowing easier deploy- antennas are shown by stars. ment of RFID along side communications networks on a common infrastruc- Converged Sensing and Communications ture, optical DAS are able to bring coverage improvements Networks Using an Optical DAS to passive UHF RFID similar to those seen in communica- Radio over fiber research to date has focused on providing tions networks. Figure 4 shows the returned power from wireless communications services, reaching commercial de- a passive UHF RFID tag in a single and 3-antenna DAS. A ployment in many cases. However, future requirements for level of 285 dBm represents nulls where no returned signal

18 IEEE LEOS NEWSLETTER February 2009 link,” presented at the IEEE Topical Conf. on Microwave Improved Performance in a Multiantenna DAS with Photonics, Seoul, 2005. Frequency and Phase Diversity Over a Single Antenna DAS –55 3. X. Qian et al., “Application of semiconductor optical am- Single Antenna Triple Antenna DAS with plifiers in scalable switched radio-over-fiber networks,” Optimization –60 presented at the IEEE Topical Conf. on Microwave Photo- nics, Seoul, 2005. –65 4. F. Yang, M. J. Crisp, R. V. Penty, and I. H. White, “Silicon avalanche photodiodes for low cost, high loss short wavelength –70 radio over fiber links,” CLEO, submitted for publication. 5. M.J. Crisp, E.T. Aw, A. Wonfor, R.V. Penty, and I. H. –75 White, “Demonstration of an SOA efficient 32332 opti- –80 cal switch for radio over fiber distribution,” OFC, vol. 7,

Received Power (dBm) 2008. 6. M.J. Crisp, S. Li, A. Watts, R.V. Penty, and I. H. White, –90 “Uplink and downlink coverage improvements of 802.11g 0 200 400 600 800 1,000 Distance (cm) signals using a distributed antenna network,” J. Lightwave Technol., vol. 25, pp. 3388–3395, 2007. RFID system and an RFID system using a 3-antenna DAS. −85 7. M. J. Crisp, R. V. Penty, and I. H. White, “Dual function dBm has been used to represent nulls where no returned power sensing and multiservice communications radio over fiber could be detected. network using second harmonic suppression,” OFC, to be published. from the tag can be detected. Through the use of the DAS, 8. S. Sabesan, M. J. Crisp, R. V. Penty, and I. H. White, the number of nulls has been reduced from 28% to 0%, and a “Demonstration of improved passive UHF RFID coverage 10 dB increase in the returned power has been achieved over using optically-fed distributed multi-antenna system,” to an 8 m range. Similar improvements have been demonstrated be presented at RFID Conf. over a range up to 18 m using a commercial RFID reader and an optical DAS [8]. Glossary of Terms Future potential 2G/3G – Second/Third Generation (cellular phones) Optical DAS are reaching a level of maturity where commer- DAS – Distributed Antenna System cial installations are becoming widespread. However, with the DAN – Distributed Antenna Network constantly increasing bandwidth demands and evolving sens- DVB-H – Digital Video Broadcast - Handheld (European stan- ing and communications standards, a large body of research dard for digital broadcast television for mobile devices, and is a remains to be carried out. variant of the Terrestrial standard, “DVB-T”, that was defined Topics of interest include: for non-mobile devices. • Lower cost optical links – for example, recent research on LAN – Local Area Network polymer optical fiber has demonstrated very promising LTE – Long-Term Evolution (The standard is 3GPP Release 8, RoF performance. for many a “4G” technology) • Intelligent DANs - to date DANs have been largely static RFID – Radio Frequency Identification (RFID) systems typi- although research has shown that RoF optical switching is cally consist of a tag that contains information identifying an possible. Combining a switched DAN with sensing will item. Ultra-high frequency (UHF) RFID tags can operate produce a new intelligent infrastructure, with the abil- from 300 MHz to 3 GHz, but typically between 866 MHz to ity to self-manage, further improving the quality of the 960 MHz. They can send information faster and further than services offered and the possibility to become resilient to high and low frequency tags but require greater power. failure. TDD – Time Division Duplex • MIMO systems – A few demonstrations of MIMO on RoF TETRA – Terrestrial Trunked Radio, the ETSI standard for have been carried out, but DAN systems have only used digital trunked radio communications multiple antennas to achieve diversity. Spatial multiplex- Wifi – Wireless Fidelity (This usually refers to a wireless ing within a DAN has the potential for greatly increased networking system that uses any of the 802.11 (including bandwidths. 802.11a/b/g) wireless networking protocols. The Wi-Fi standard is set by the Wi-Fi Alliance.) References WiMAX – Worldwide Interoperability for Microwave Access 1. http://www.zinwave.com (Technology to deliver wireless broadand access over distances 2. P. Hartmann, X. Qian, A. Wonfor, R. V. Penty, and I. H. of up to 6 miles, an alternative to broadband access via a fixed White, “1-20GHz directly modulated radio over MMF line local loop. WiMAX is based on IEEE 802.16)

February 2009 IEEE LEOS NEWSLETTER 19 Biographies sity of Cambridge, having previously held academic posts at the Michael J. Crisp (S’07) received the B.A. degree from the Uni- Universities of Bath and Bristol. His research interests include versity of Cambridge, U.K., the M.Eng. degree from the Uni- high speed optical communications systems, wavelength conver- versity of Cambridge in 2005, and is currently working toward sion and wavelength division multiplexing (WDM) networks, the Ph.D. degree in optical communications at the University optical amplifiers, optical nonlinearities for switching applica- of Cambridge, conducting research on RoF. tions, and high power semiconductor lasers. He has been the author of more than 400 refereed journal and conference papers. Sithamparanathan Sabesan (S’08) was born in Jaffna, Sri Prof. Penty is the Editor-in-Chief of IET Optoelectronics. Lanka, in 1984. He received the B.Eng. (Hons) degree from the University of Sheffield, Sheffield, U.K., in 2007, and the Ian H. White (S’82–M’83–SM’00–F’04) received the B.A. MPhil degree in Engineering from the University of Cam- and Ph.D. degrees from the University of Cambridge, U.K., bridge, Cambridge, U.K., in 2008. He is currently working in 1980 and 1984, respectively. He was appointed as Research toward the Ph.D. degree in optical and wireless communica- Fellow and Assistant Lecturer at the University of Cambridge tions, conducting research on passive UHF RFID and RoF at before he became Professor of Physics at the University of Bath, the same University. He was with ARM, Cambridge, U.K. as U.K., in 1990. In 1996, he moved to the University of Bris- a student IP Electronic Engineer in 2007. Mr. Sabesan was tol, U.K., where he was Professor of Optical Communications, awarded a Sir William Siemens Medal in 2006. Head of the Department of Electrical and Electronic Engineer- ing in 1998, and Deputy Director of the Centre for Communi- Richard V. Penty (M’00-SM’08) received the Ph.D. degree in cations Research. He returned to the University of Cambridge engineering for his research on optical fiber devices for signal in October 2001 as van Eck Professor of Engineering. He is the processing applications from the University of Cambridge, U.K., Head of the School of Technology and of Photonics Research in 1989. He was a Science and Engineering Research Council at the University of Cambridge. He has published in excess of (SERC) Information Technology Fellow, again at the University 400 publications and 20 patents. Prof. White is currently an of Cambridge, working on all optical nonlinearities in waveguide Editor-in-chief of Electronics Letters and a member of the Board devices. He is currently a Professor of Photonics at the Univer- of Governors of the IEEE LEOS Society.

20 IEEE LEOS NEWSLETTER February 2009 Research Highlights Enabling Microwave Photonic Technologies for Antenna Remoting Dr Dalma Novak

PHARAD, LLC, GLEN BURNIE, MD by third-order intermodulation distortion products (IMD3) WWW.PHARAD.COM, EMAIL: [email protected] which are important to suppress since they typically lie within the frequency band of interest. The adaptive FF linearization The low-loss, electromagnetic interference free, and wide architecture incorporates three main parts: a signal cancellation bandwidth microwave signal transport over lightweight and circuit (SCC), an error cancellation circuit (ECC), and a control non-conducting photonic links offers the potential for provid- circuit (CC). Control loops are also utilized to provide real-time ing new capabilities, significant performance improvements, adaptive capability whereby the RF photonic link can maintain and design flexibility to a diverse range of microwave systems system performance during changing operating conditions. As [1,2]. In this article we describe some enabling microwave their names imply, the SCC and ECC cancel the signal and er- photonic technologies for fiber-optic antenna remoting in RF ror respectively, forming the foundation of a conventional FF sensor systems and wireless communication networks. linearization system. As highlighted in Figure 1, the input RF signal to the FF Adaptive Feedforward Linearization for High linearized RF photonic circuit is split into three paths. In the Dynamic Range RF Photonic Links SCC, the amplitude and phase of one of the copies of the input A major hurdle to fully realizing the benefits of photonic sig- signal (represented by the ‘DA, Dw’ block) is adjusted for maxi- nal remoting in microwave systems is the high dynamic range mum signal cancellation when it is combined with a portion of requirement of many applications, limited by the inherent the main optical path after optical-to-electrical (O/E) conversion nonlinearity of the electrical-to-optical (E/O) conversion pro- in a high-speed photodetector (PD). The main optical signal and cess. Several linearization schemes suitable for correcting mi- the input RF replica are arranged to have equal amplitudes and crowave photonic link nonlinearities have been demonstrated, most derived from common RF amplifier design techniques DFB Transmission such as predistortion [3,4] and feedforward RF OUT RF IN Medium [5,6] architectures. Novel electro-optical EOM PD modulator designs [7] have also been pro- SCC ECC posed and demonstrated. The majority PD PD of these implementations, however, have SCC ΔA, Δϕ Σ ECC ΔA, Δϕ EOM Σ been characterized by limited operational RF CC and/or instantaneous bandwidths, as well Detector DFB as the achievable Spurious Free Dynamic CC ΔA, Δϕ Tunable Range (SFDR). Bandpass Recently, in collaboration with research- Filter ers at Johns Hopkins University Applied Physics Laboratory, we developed a linear- Control Circuit ized high SFDR RF photonic link with multi-octave operational bandwidth and an instantaneous bandwidth approaching 1 GHz [8]. Our approach for correcting the performance-limiting E/O nonlinear distortion was based on the use of feedforward (FF) linearization. Figure 1 shows the high level architecture of the linearized circuit which is based on an intensity modulation direct detection link and also incorporates adaptive functionality. As shown in the diagram, an electro-optic modulator (EOM) encodes the input RF signal(s) onto an optical carrier. Distortion due to this Figure 1. Top: Block diagram of the wideband adaptive FF linearization transmission nonlinear transfer function is dominated circuit architecture; Bottom: Photograph of the RF photonic transceiver module.

February 2009 IEEE LEOS NEWSLETTER 21 opposite phase when combined; the signal component is then strength at their specific locations. A control circuit interfaces cancelled leaving only the error. The error signal is then prepared between the various components in the control loops and also by amplitude and phase adjustment and encoded with a second executes the control algorithms. Further information regard- EOM in the ECC before being optically coupled back into the ing the adaptive algorithms can be found in [7]. main transmission path. Proper error cancellation occurs when The linearity performance of the adaptive FF linearized RF these two signals are equal in amplitude and opposite in phase photonic circuit was measured over the RF component limited and ideally, an undistorted copy of the input RF signal through operational bandwidth of 1–20 GHz using the test configura- the transmission medium at the final O/E conversion will result. tion shown in Figure 2 with an input test signal comprising The CC in the adaptive FF linearized RF photonic link is effec- a two-tone RF signal centered at 15 GHz. Fundamental and tively a signal cancellation loop that monitors the performance IMD3 levels were measured using a high frequency RF spec- of the circuit. It operates in a similar way to the SCC; combining trum analyzer. Figure 2 shows an example of the measured the amplitude and phase adjusted section of the undistorted in- IMD3 suppression performance and presents the measured RF put RF signal and a fraction of the transmitter output to isolate spectra of the detected optical output signal with and without the remaining distortion component of the output signal. adaptive FF linearization implemented. IMD3 suppression of The operating bandwidth of the circuit shown in Figure third order intermodulation distortion products by 20–25 dB 1 is dependent only on the frequency response of the compo- in a 30 MHz instantaneous bandwidth (IBW) was achieved nents and the path length difference of the delay lines at the with the adaptive FF linearized circuit. The SFDR of the multi- signal and error combination points. Commercial-off-the-shelf octave adaptive FF linearized RF photonic link was determined devices were used to realize a multi-octave operational band- from the IMD3 suppression measurements and the measured width. Each control loop in the adaptive FF circuit includes noise floor of the system. Table I summarizes the measured amplitude and phase tuning hardware as well as a wideband linearity performance of the link at instantaneous bandwidths RF detector to provide feedback on the loop performance. of 30 MHz and 300 MHz, highlighting the SFDR. Table II The detectors provide a voltage proportional to the RF signal presents the measured SFDR at a center frequency of 10 GHz

RF Synthesizer #1 To Fiber From Fiber RF Spectrum Link Link Analyzer

RF Synthesizer #2

–20 –20

–30 –30

–40 –40

–50 –50

–60 –60

–70 –70 RF Power (dBm) RF Power (dBm) –80 –80

–90 –90

–100 –100

15 15 14.98 14.99 15.01 15.02 14.98 14.99 15.01 15.02 14.975 14.985 14.995 15.005 15.015 15.025 14.975 14.985 14.995 15.005 15.015 15.025 Frequency (GHz) Frequency (GHz) (a) (b)

Figure 2. Top: Test configuration used to measure the linearity performance of the wideband adaptive FF linearized RF photonic transceiver; Below: Measured IMD3 suppression of the wideband RF photonic link at 15 GHz with a 10 MHz two-tone spacing: (a) without and (b) with adaptive FF linearization.

22 IEEE LEOS NEWSLETTER February 2009 SFDR (dB-Hz2/3) Center Frequency 300 MHz Band (GHz) 30 MHz IBW IBW

S-band 3 112.97 111.86 z Driven C-band 6.5 111.76 111.90 Patch x y Parasitic X-band 10 114.03 111.16 Patch Microstrip Ku-band 15 115.24 111.07 Electrode

Table I. Measured SFDR of the multi-octave adaptive FF linearized RF photonic link at 30 MHz and 300 MHz instantaneous bandwidth. Figure 3. Schematic of a hi-lo stacked patch antenna that can be integrated with photonic materials. Instantaneous Bandwidth (MHz) SFDR (dB-Hz2/3)

3 113.91 0

30 114.03 –5 150 113.81 –10 300 111.16 –15 600 113.10

Return Loss (dB) –20 900 111.40 –25 Table II. Measured SFDR of the multi-octave adaptive FF lin- 33.545 4.5 5.5 6 earized RF photonic link at 10 GHz for different instantaneous Frequency (GHz) bandwidths. Figure 4. Return loss response of a hi-lo stacked patch antenna designed for operation at 5 GHz and to be integrated with InP. for increasing instantaneous bandwidths. SFDR values in excess of 111 dB-Hz2/3 were achieved for instantaneous bandwidths approaching 1 GHz. the photonic device material where the RF electrode structure is developed (a microstrip transmission line is shown in Figure 3). Antenna Technologies for Fiber Optic Another patch antenna created on a separate combination of di- Antenna Remoting Links electric layers is then electromagnetically coupled to the driven High performance RF photonic links are not the only require- antenna. This second radiator enhances the overall efficiency ment for fiber optic antenna remoting applications. Efficient, and bandwidth of the antenna. low loss interfaces between the guided optical medium and the Figure 4 shows the return loss performance of a hi-lo stacked free-space microwave link are also necessary for maximizing patch antenna that was designed for operation at approximately overall system performance. To address this challenge, Pharad 5 GHz and for integration with InP. As can be seen from the re- is developing unique antenna technologies that are compat- sponse, a −10 dB return loss bandwidth of approximately 20% ible with efficient integration with common photonic materi- was achieved using the radiator structure shown in Figure 3. als such as lithium niobate and indium phosphide. In order Furthermore, the overall efficiency of the antenna was greater to support wideband fiber optic antenna remoting links, we than 92%, even though the driven patch was developed on a e . are also focusing on broadband antenna structures that can be high dielectric constant material ( r 11). directly integrated with optical transmitters and receivers. The challenge lies in not compromising either the overall antenna Conclusion bandwidth or the efficiency of the RF photonic link, since con- The growing spectral demands of existing microwave systems, ventional antennas developed on high dielectric constant mate- as well as new technology opportunities such as high data rate rials typically feature poor efficiency and limited bandwidth. wireless communications, make photonic signal remoting ca- Low profile patch-based antennas can provide efficient, pabilities likely to see increased insertion opportunities in the broadband radiator solutions that can be either readily devel- near as well as far future. High performance RF photonic link oped on photonic materials, or electromagnetically coupled to and antenna technologies are key to realizing these systems. them. Figure 3 shows a variation of this type of radiator structure, known as a hi-lo stacked patch [8, 9], which can be in- Acknowledgement tegrated on photonic materials and still provide an inherently The development of the wideband adaptive RF photonic broadband, efficient solution. The patch antenna is created on transceiver was supported in part by the Naval Air Systems

February 2009 IEEE LEOS NEWSLETTER 23 Command, Patuxent River, MD. Key collaborators at our 3. C. H. Cox III, E. I. Ackerman, G. E. Betts, and J. L. research partner, Johns Hopkins University Applied Physics Prince, “Limits on the performance of RF-over-fiber links Laboratory are Dr. Thomas Clark and Mr. Sean O’Connor. and their impact on device design,” IEEE Trans. Microwave Theory Tech., vol. 54, no. 2, pp. 906–920, 2006. About the Author 4. R. Sadhwani and B. Jalali, “Adaptive CMOS predistortion lin- Dalma Novak is a Vice-President at Pharad, LLC located in earizer for fiber-optic links,” J. Lightwave Technol., vol. 21, pp. Glen Burnie, Maryland. She has over 16 years of experience in 3180–3193, 2003. the microwave photonics and optical communications fields, 5. L. Roselli, V. Borgioni, F. Zepparelli, F. Ambrosi, with more than 250 publications in these areas. From 1992– M. Comez, P. Faccin, and A. Casini, “Analog laser pre- 2004 Dr. Novak was a faculty member in the Department of distortion for multiservice radio-over-fiber systems,” J. Electrical and Electronic Engineering at The University of Mel- Lightwave Technol., vol. 21, pp. 1211–1223, 2003. June 2001–December 2003 she was a Technical Section Lead at 6. L. S. Fock and R. S. Tucker, “Simultaneous reduction of in- Dorsál Networks, Inc. and later at Corvis Corporation where she tensity noise and distortion in semiconductor lasers by feed- led cross-disciplinary R&D teams developing networking hard- forward compensation,” Electron. Lett., vol. 27, pp. 1297– ware for telecommunications applications. In 2007 Dr. Novak 1299, 1991. was elected to the grade of IEEE Fellow for contributions to 7. S. H. Park and Y. W. Choi, “Significant suppression of the enabling technologies for the implementation of fiber radio sys- third intermodulation distortion in transmission system tems. She received the PhD degree in Electrical Engineering with optical feedforward linearized modulator,” IEEE Pho- from the University of Queensland, Australia, in 1992. ton. Technol. Lett., vol. 17, no. 6, pp. 1280–1282, 2005. 8. R. B. Waterhouse, “Stacked patches using high and low References dielectric constant material combination,” IEEE Trans. 1. S. A. Pappert, R. Esman, and B. Krantz, “Photonics for RF Antennas Propagat., vol. 47, pp. 1767–1771, 1999. Technology Conf., San Diego, CA, Oct. 2008, pp. 5–6. 9. W. S. T. Rowe and R. B. Waterhouse, “Efficient wide- 2. J. Capmany and D. Novak, “Microwave photonics com- band printed antennas on Lithium Niobate for OEICs,” bines two worlds,” (Invited Paper), Nature Photon., vol. 1, IEEE Trans. Antennas Propagat., vol. 51, pp. 1413–1415, no. 6, pp. 319–331, June 2007. 2003.

24 IEEE LEOS NEWSLETTER February 2009 President’s Column

(continued from page 3) be more news about this exciting venture shortly, but there will be an opportunity for all LEOS members to contribute to the success of the journal simply by submitting their best papers! I also congratulate the newly elected members of the Board of Governors: • Shun Lien Chuang (University of Illinois) • Jeffrey A. Kash (IBM Research, NY) • Michal Lipson (Cornell University, NY) • Ian White, (University of Cambridge, United Kingdom) and thank the outgoing elected members, Markus Amann, Kent Choquette, Hideo Kuwahara and Carmen Menoni.

Changes in the society The Society will be launching several new initiatives this year, and I have selected a few highlights. In addition to the IEEE Photonics Journal, the IEEE/OSA Journal of Optical Communications and Networking ( JOCN ) will start in 2009. The formal launch will be in April, with a major publicity drive at OFC. The other co-sponsors are the IEEE Communications Society and OSA. The JOCN will offer compre- hensive coverage of advances in theoretical and practical aspects of state-of-the-art optical communication systems and networks. It is complementary to the Journal of Lightwave Technology, which is oriented towards device and hardware implementation. Please consider publishing relevant papers in this Journal. The Society will be co-sponsoring the IEEE Photovol- taic Specialists Conference for the first time. This reflects the increasing importance of photonics in meeting the needs for renewable energy. There is also a major change in the Technical Commit- tee structure, with the 18 old committees being reduced to 12 from 1st January. This change is intended to allow for the creation of new TCs in areas of increasing importance.

A new personal emphasis The observant amongst you will have noticed a change in my affiliation in the list of Society officers. Although I remain affiliated to both the University of Glasgow and Intense Ltd, I will now be spending the bulk of my time in the University – another significant change from the New Year.

Building the LEOS community Finally, some news about membership. As we enter 2009, Society membership has risen above 7000, the highest December membership total since 2005. This excellent news reflects both the relevance and importance of the field of photonics and the high quality products LEOS offers to the field. I would like to welcome the new members and to thank everyone who has been involved in their recruitment. This is a tremendous achievement in the current economic climate, and I am sure we can continue to grow as we expand into new technical areas and develop our conferences and journals.

February 2009 IEEE LEOS NEWSLETTER 25 News

2009 IEEE/LEOS Fellows

Congratulations! Please join us in congratulating the 16 LEOS members who became IEEE Fellows this year. It’s a significant honor that is based on major technical contributions, leadership, and service to the Institute and the profession. The deadline for 2010 Fellow nominations is March 1. For more information, and to learn how to submit a nomination, check out the Fellows page on the IEEE portal at: http://www.ieee.org/web/membership/fellows/index.html

Piet Demeester John Cartledge Arthur Lowery Ghent University, IBBT - Gent, Queen’s University, Dept of Electrical Monash University, Dept. Electrical & Belgium and CE Walter Light Hall - Kingston, Computer Systems Eng. - Victoria, For contributions to optical communication ON, Canada Australia networks and technologies For contributions to modulation dynamics For leadership in computer modeling of op- of optical devices tical communication systems Ching-Ting Lee National Cheng Kung University, Weng Chow Paul McManamon College of EE & CS - Tainan, Taiwan Sandia National Laboratories - Air Force Research Laboratory (AFRL/ For contributions to galium nitride-based Albuquerque, NM, U.S.A. RYRT) - Dayton, OH, U.S.A. optoelectronic and electronic devices For contributions to semiconductor-laser theory For contributions in optical phased array and laser radar Andrew Chraplyvy Keren Bergman Bell Laboratories, Alcatel-Lucent - Klaus Petermann Columbia University, Dept. of Elec- Holmdel, NJ, U.S.A. Technische Universitat Berlin - Berlin, trical Engineering - New York, NY, For contributions to high-capacity optical Germany U.S.A. communications systems, dispersion man- For contributions to optical communications For contributions to development of optical agement and non-zero dispersion fiber technology interconnection and transport networks Martin Dawson Chi Sun David Brady University of Strathclyde, Institute of National Taiwan University, Graduate Fitzpatrick Institute for Photonics & Photonics - Glasgow, Scotland, UK Institute of Photonics and Optoelec- Dept. of Electrical Engineering Pratt For contributions to compound semiconduc- tronics - Taipei, Taiwan School of Engineering, Duke Univer- tor optoelectronics For contributions to high resolution medical sity (DISP) - Durham, NC, U.S.A. microscopy and nano ultrasonic imaging For contributions to computational optical Alan Gnauck imaging and spectroscopy Bell Laboratories, Alcatel-Lucent - Peter Winzer Holmdel, NJ, U.S.A. Bell Laboratories, Alcatel-Lucent - Gary Carter For contributions to high-capacity optical Holmdel, NJ, U.S.A. University of Maryland Baltimore communications systems For contributions to high-speed digital County, Computer Science & EE optical modulation in transport networks Dept. - Baltimore, MD, U.S.A. Franz Kaertner For contributions to understanding non- Massachusetts Institute of Technology - linear and polarization effects in optical Cambridge, MA, U.S.A. fiber communications systems For contributions to ultrafast optics

26 IEEE LEOS NEWSLETTER February 2009 News (cont’d)

2009 IEEE/LEOS Award Reminders!!

The deadline for submitting nominations for the following awards is 30 April. William Streifer Scientific Achievement Award Engineering Achievement Award Aron Kressel Award and Distinguished Service Award In order to facilitate the nomination procedure, nomination forms are found on pages 28 and 29.

IEEE/LEOS William Streifer or to a group for a single contribu- form of publications, patents, products, Scientific Achievement tion of significant work in the field. or simply general recognition by the Award No candidate shall have previously professional community that the indi- The IEEE/LEOS William Streifer received a major IEEE award for the vidual cited is the agreed upon origi- Scientific Achievement Award is giv- same work. Candidates need not be nator of the advance upon which the en to recognize an exceptional single members of the IEEE or LEOS. award decision is based. The award scientific contribution that has had a may be given to an individual or significant impact in the field of lasers IEEE/LEOS group, up to three in number. and electro-optics in the past 10 years. Aron Kressel Award It may be given to an individual or to The IEEE/LEOS Aron Kressel Award IEEE/LEOS Distinguished a group for a single contribution of is given to recognize those individuals Service Award significant work in the field. No can- who have made important contribu- The IEEE/LEOS Distinguished Service didate shall have previously received a tions to opto-electronics device tech- Award was established to recognize an major IEEE award for the same work. nology. The device technology cited exceptional individual contribution of Candidates need not be members of is to have had a significant impact on service which has had significant ben- the IEEE or LEOS. their applications in major practical efit to the membership of the IEEE systems. The intent is to recognize Lasers and Electro-Optics Society as a IEEE/LEOS Engineering key contributors to the field for de- whole. This level of service will often Achievement Award velopments of critical components, include serving the Society in several The IEEE/LEOS Engineering Achieve- which lead to the development of capacities or in positions of significant ment Award is given to recognize an systems enabling major new services responsibility. Candidates should be exceptional engineering contribution or capabilities. These achievements members of LEOS. that has had a significant impact on should have been accomplished in a The list of previous winners and the development of laser or electro- prior time frame sufficient to permit nomination forms can be found on optic technology within the past 10 evaluation of their last impact. The the LEOS Home Page http://www. years. It may be given to an individual work cited could have appeared in the i-LEOS.org.

Call for Fellow Nominations

On the Lookout for tal of 375 000 members. While ries: application engineer, educa- a Few Good Fellows many view Fellows as visionar- tor, research engineer, or technical by Rosann Marosy ies, pioneers, technology leaders, leader. It’s not too early to nominate an IEEE or influential business executives, To submit a nomination or learn senior member for the Fellow class of you probably know them as your more about these categories and the 2010. The deadline is 1 March 2009. friends or colleagues. So take the Fellow Program, visit the Fellow This prestigious group now time to nominate someone you Web site at http://www.ieee.org/ numbers 6000 out of IEEE’s to- know in one of four Fellow catego- fellows

February 2009 IEEE LEOS NEWSLETTER 27 News (cont’d) Nomination Form for IEEE/LEOS Awards

Please check the appropriate award category:

Quantum Electronics (16 Feb deadline) Streifer Scientific Achievement (30 April deadline) Engineering Achievement (30 April deadline) Aron Kressel (30 April deadline)

Separate forms are available for the Distinguished Lecturer, Distinguished Service, Young Investigator, and John Tyndall Awards

1. Name of Nominee (for joint nominations, give the names, address information of the co-workers on a second sheet.

2. Nominee’s Address

3. Nominee’s Phone: Fax:

Email:

4. Proposed Award Citation (20 words or less)

5. On separate sheets attach:

a. Statement of specific contribution(s) that qualify Nominee for Award, as well as other related accomplishments (maximum of two pages).

b. Nominee’s curriculum vita

c. Endorsers: List the names, affiliations, addresses, and emails of individuals who have agreed to write letters of support. (Minimum of three supporting letters required; maximum of five permitted. No more than five letters will be reviewed by the Committee. Letters may accompany nomination or be submitted directly to IEEE LEOS prior to the nomination deadline.) Letters of recommendation are to be considered confidential and are not to be released to anyone other than IEEE-LEOS awards staff.

6. Your name:

Phone: Fax:

Email:

Send nomination information with supporting material to: IEEE/LEOS Awards Committee; 445 Hoes Lane; Piscataway, NJ 08854 Fax: +1 732-562-8434; email: [email protected] 11-07

28 IEEE LEOS NEWSLETTER February 2009 News (cont’d) Nomination Form for IEEE/LEOS Distinguished Service Award

Deadline: 30 April

1. Name of Nominee:

2. Nominee’s Address

3. Nominee’s Phone: Fax:

Email:

4. Proposed Award Citation (20 words or less)

5. Attach a description of the Nominee’s exceptional individual contribution of service that has had significant benefit to the membership of the IEEE Lasers & Electro-Optics Society as a whole. This level of service will often include serving the Society in several capacities or in positions of significant responsibility.

6. Your name:

Phone: Fax:

Email:

Send nomination information with supporting material to: IEEE/LEOS Awards Committee; 445 Hoes Lane; Piscataway, NJ 08854 Fax: +1 732-562-8434; email: [email protected] 7-06

February 2009 IEEE LEOS NEWSLETTER 29 Career Section

2008 LEOS Best Student Paper Award Recipients

The LEOS Best Student Paper Awards receive certificates of recognition 1st Place – Hyejun Ra are open to students from universi- and monetary awards ranging up 2nd Place – Liang (Luke) Tang ties whose papers have been accepted to $1000. Finalist – Andrei Faraon for presentation at the LEOS An- The results for the 2008 LEOS Best Finalist – Seth A. Fortuna nual Meeting. The top five finalists Student Paper Award are as follows: Finalist – K. Shavitranuruk

2009 IEEE/LEOS Young Investigator Award Recipient: Aydogan Ozcan

The Young Investigator Award was joined UCLA in the summer of 2007, Northrop Grumman Corporation, established to honor an individual where he is currently leading the Bio- which is the leading defense company who has made outstanding technical and Nano-Photonics Labo ratory (http:// in US. Dr. Ozcan is also the co-author contributions to photonics (broad- innovate.ee.ucla.edu/) at the Electri- of more than 70 peer reviewed re- ly defined) prior to his or her 35th cal Engineering Department. Prof. search articles in major scientific jour- birthday. Nominees must be under Ozcan’s research group is also part of nals and conferences. 35 years of age on 30 September of the UCLA California NanoSystems Insti- Dr. Ozcan is serving in the Scien- year in which the nomination is made. tute (CNSI), where he is serving as a tific Advisory Board of the Lifeboat Candidates need not be members of member of the research committee. Foundation, and is a member of the the IEEE or LEOS. The deadline for Dr. Ozcan holds 11 US patents, program committee of SPIE Photon- nominations is 30 September. ics West Conference. He also serves as The 2009 IEEE/LEOS Young In- a panelist and a reviewer for National vestigator Award will be presented Science Foundation and for Harvard- to Aydogan Ozcan, “for his pioneer- MIT Innovative Technology for Medi- ing contributions to non-destructive cine Program. nonlinear material characterization For his work on lensfree on-chip techniques, near-field and on-chip imaging and diagnostic tools, Prof. imaging and diagnostic system.” Ozcan received the 2008 Okawa The presentation will take place Foundation Research Award, given during the Plenary Session held on by the Okawa Foundation in Japan. 3 June at CLEO/IQEC - Conference Prof. Ozcan also received the 2009 on Laser and Electro-Optics and the IEEE Lasers & Electro-Optics So- International Quantum Electronics ciety’s (LEOS) Young Investigator Conference, 31 May–5 June, Balti- Award. He is also the recipient of a more Convention Center, Baltimore, National Science Foundation Award Maryland, USA. on “Biophotonics, Advanced Imag- Aydogan Ozcan received his Ph.D. Aydogan Ozcan ing, and Sensing for Human Health” degree at Stanford University Electri- for his on-chip plasmonic microsco- cal Engineering Department in 2005. 1 UK patent and another 9 pending py work. Dr. Ozcan was also awarded After a short post-doctoral fellowship patent applications for his inventions the Presidential Fellowship from the at Stanford University, he is appointed in nanoscopy, wide-field imaging, Turkish Ministry of Education in as a Research Faculty Member at Har- nonlinear optics, fiber optics, and 1996 (declined). vard Medical School, Wellman Center optical coherence tomography. All of Dr. Ozcan is a member of IEEE, for Photomedicine in 2006. Dr. Ozcan his patents are currently licensed by LEOS, OSA, SPIE and BMES.

30 IEEE LEOS NEWSLETTER February 2009 Career Section (cont’d)

2009 IEEE David Sarnoff Award Recipients: Yasuhiko Arakawa, Kerry John Vahala, and Kam Yin Lau

The IEEE David Sarnoff Award was established in 1959 based on quantum effects. His main achievement includes through agreement between the RCA Corporation and the proposal of the concept of quantum dots and their ap- American Institute of Electrical Engineers, and continued plication to quantum dot lasers (‘82), pioneering theo- by the Board of Directors of the IEEE. In 1989, sponsor- retical and experimental work on quantum size effects on ship of the award was assumed by the Sarnoff Corporation. lasing dynamics in semiconductor lasers (‘84–‘86), dis- It may be presented each year to an individual or team up covery of exciton-polariton Rabi-vacuum oscillation in to three in number for exceptional contributions to elec- semiconductor nanocavity (‘92), discovery of continuum tronics. For additional information on IEEE Technical in density of states in quantum dots by PLE (‘92), the Field Awards and Medals, to view complete lists of past achievement of high temperature stability in high speed recipients or to nominate a colleague or associate for IEEE quantum dot lasers (‘04) , the first demonstration of Technical Field Awards and Medals, please visit http:// single photon sources at telecommunication wavelength www.ieee.org/awards. (‘04) and the highest operation temperature of 200 K The 2009 IEEE David Sarnoff Award will be presented achieved in all-solid single photon sources by using GaN to Yasuhiko Arakawa, Kerry John Vahala, and Kam Yin quantum dots (‘06). Lau “for seminal contributions to improved dynamics of Dr. Arakawa is a Fellow of the IEEE, JSAP and IE- quantum well semiconductor lasers.” The presentation will ICE. He is a member of Science Council of Japan. He has take place during the Plenary Session held on 24 March published about 400 papers in scientific journals and has at OFC - Conference on Optical Fiber Communication, given invited talks more than 200 times at international 22–26 March, San Diego Convention Center, San Diego, conferences. He has received a number of awards, includ- California, USA. ing Young Scientist Award of International Symposium on Compound Semiconductors (1988), IBM Science Award Yasuhiko Arakawa was (1992), ISCS Quantum Device Award (2002), IEEE/LEOS born on 26 November William Streifer Scientific Achievement Award (2004), Leo 1952 in Aichi Prefecture, Esaki Prize (2004), The Wall Street Journal Technology In- Japan. He obtained a B.S. novation Runner-Up Award (2006), Fujiwara Prize (2007) degree in 1975 and a Ph.D. and Prime Minister Award (2007). degree in 1980, respective- Dr. Arakawa and his wife, Kaoru, reside in Shin- ly, from the University of Yurigaoka, Kawasaki, Japan. Ka oru is a Professor of Tokyo, both in Electronics Meiji University, working on signal processing and bio- Engineering. information technology. They have two children, Akihiko Dr. Arakawa’s first pro- and Hiroaki. fessional association was Yasuhiko Arakawa with the University of To- Kerry Vahala is Ted and kyo as an Assistant Profes- Ginger Jenkins Professor sor in 1980. In 1981 he became an Assistant Professor of Information Science and at the University of Tokyo. In 1993, he was promoted Technology and Profes- a Full Professor of the University of Tokyo. He is now a sor of Applied Physics at Professor of Research Center for Advanced Science and Caltech. He also received Technology, the University of Tokyo and also the Direc- his Ph. D. (85) in Applied tor of Institute for Nano Quantum Information Electron- Physics at Caltech. ics, the University of Tokyo. From 1984 to 1986 for two His research on quantum years, he was a visiting scientist of California Institute of well lasers predicted and Technology, staying with Professor Amnon Yariv. During later demonstrated dynami- his PhD, he worked on communication theory, propos- cal improvements using Kerry Vahala ing Extended Duo-binary Code matched to optical com- engineered nanostructures munication channels. When he joined the University of as active layers. These features contributed to the success Tokyo, he switched his research field to photonic devices of quantum well semiconductor lasers in communications

February 2009 IEEE LEOS NEWSLETTER 31 Career Section (cont’d)

systems. Dr. Vahala has also pioneered the subject of high-Q Prof. Lau received the microcavities, including applications to micro-scale Raman IEEE William Streifer Sci- and parametric sources, cavity opto-mechanical phenomona, entific Achievement and as well as cavity QED on-a-chip systems. the Distinguished Lecturer Dr. Vahala is a Fellow of the Optical Society of Awards from IEEE LEOS America, was the first recipient of the Richard P. Feynman in 1996 and the Nicho- Hughes Fellowship, and is also a recipient of an Alexan- las Holonyak Award from der Von Humboldt Research Award. He received both the OSA in 2008. He was As- Presidential Young Investigator and Office of Naval Re- sociate Professor of E.E. at search Young Investigator Awards, has 28 patents, over 150 Columbia University from publications, and edited the book, “Optical Microcavities.” 1988–90, and a professor He was program co-chair for CLEO 99 and General Chair in the EECS department Kam Y. Lau for CLEO 2001. at U.C. Berkeley since 1990. He co-found LGC Wireless, Inc. (“L” of “LGC”). Kam Y. Lau received simultaneous B.S. /M.S. in 1978, LGC delivers cost-effective in-building wireless cover- and Ph.D. in 1981, all from Caltech in Electrical Engi- age and capacity solutions. With over 10,000 large-scale neering. Upon graduation, he joined Ortel Corporation as systems installed in .100 countries on every continent, founding staff/chief scientist. His fundamental research its technology becomes de-facto industrial standard. in high-speed semiconductor laser dynamics provides the LGC Wireless was acquired by ADC Telecom (Nasdaq : foundation for fiber-optic transmitter products leading to ADCT) in 2007. Ortel’s successes – its IPO and subsequent acquisition by In 2005 Prof. Lau assumed Emeritus status and retired Lucent/Agere. from active duties at U.C. Berkeley.

“Nick” Cartoon Series

32 IEEE LEOS NEWSLETTER February 2009

Membership Section

The Italian LEOS Chapter doubles as Chapter of the Year of both Region 8 and Society Tiziana Tambosso – LEOS Italian Chapter Chair

The LEOS (Lasers and Electro Optics Society) Italian our Chapter have been: the electronic election of Officers Chapter has been recognized twice this year. Firstly, in through the web, using IEEE e-Notice support; the electron- February, it was awarded Region 8 Chapter of the Year for ic newsletters for Italian LEOS members using e-Notice; two Large Chapters (1001 Membership) by the CCSC Com- new awards to recognize the best paper published on LEOS mission. The award was received in Malta by Silvano Do- journals by young researchers and the Distinguished Student nati, Founder and previous Chair of the Chapter, and now award (see our web for details). We have also taken part in Italy Section Chair, on behalf of the present Chair Tiziana defining the Memorandom of Understanding between LEOS Tambosso. The award was presented by IEEE President and the National Electronic Engineer Society AEIT. L.Terman and by Region 8 President J.G. Remy. Also worthy of mention is the serie of WFOPC Confer- Later in the year, when the LEOS Society announced the ences initiated by T.Tambosso and S. Donati, on Fiber Optics annual report, the Italian Chapter was recognized as the and Passive Components. The WFOPC editions were run in most prominent in terms of Membership Increase (118%), Pavia in 1998 and 2000, Glasgow (by the Scotland Chapter) Conferences and workshops organized (12 in the year), and in 2002, Palermo (back to Italy) in 2005, and finally Taiwan Special events, in particular the 30th LEOS anniversary (R.o.C., by the Taipei Chapter) in 2007. A second Confer- celebrations, that the LEOS Italian Chapter held twice, in ence series, ODIMAP, on Optical Distance Measurements Rome University La Sapienza (January 30, 2008), with a with Lasers and Applications, started in Nantes (France) in DVD recording of the speeches and Rome University TV 1997, continuing at Pavia University in 1999 and 2001, broadcasting, and in Pavia University (March 14, 2008). Oulu (Finland) in 2004, and subsequently in Madrid (2006). LEOS Italian Chapter contributed to the First Winter All these Conferences were supported with Special Issues of Topical initiative with three different Topics proposed and Journals: in particular the IEEE Journal of Selected Topics chaired by Chapter Executive Committee members and in Quantum Electronics for WFOPC and Optical Engineer- Italian members. Most recent innovations introduced in ing, and Journal of Optics-A for the ODIMAP.

LEOS Italian Chapter Secretary S.M. Pietralunga (left) receives LEOS Italian Chapter Chairperson T.Tambosso (left) with the 2008 LEOS Chapter of the Year award from the hands of LEOS Italy Chapter Founder and Italy Section Chair S. Donati LEOS President J. Marsh (right). (right).

34 IEEE LEOS NEWSLETTER February 2009 Membership Section (cont’d)

With this recognition, the LEOS Italian Chapter, which is also celebrating its 10th anniversary in 2007, received a total of 7 awards: Most Improved Chapter 1998, Most Improved Chapter 1999, Chapter of the Year Society 2001, Most Innovative Chapter 2002, Chapter of the Year R8 2002, Chapter of the Year R8 2007, and Chapter of the Year Society 2008. The Italian LEOS Chapter has been chaired by Tiziana Tambosso since 2002 (re-elected four times). Tiziana, of Tambosso & Associates, was formerly a research manager at Telecom Italia R&D Center (Torino). For more details on the Italy Chapter activities see the website http://www.unipv.it/leos. T. Tambosso e-mail: [email protected] (for any question, suggestions S. Donati (co-Chair of WFOPC 2007) in front of WFOPC 2007 and proposal of cooperation please do not hesitate to con- Panel, at the Graduate Institute of Electrooptical Engineering tact me) my website: http://www.studiotambosso.it (GIOE) of Taipei (Taiwan).

Benefits of IEEE Senior Membership

There are many benefits to becoming an IEEE Senior Member:

• The professional recognition of your peers for technical and professional excellence • An attractive fine wood and bronze engraved Senior Member plaque to proudly display. • Up to $25 gift certificate toward one new Society membership. • A letter of commendation to your employer on the achievement of Senior member grade (upon the request of the newly elected Senior Member.) • Announcement of elevation in Section/Society and/or local newsletters, newspapers and notices. • Eligibility to hold executive IEEE volunteer positions. • Can serve as Reference for Senior Member applicants. • Invited to be on the panel to review Senior Member applications.

The requirements to qualify for Senior Member elevation are a candidate shall be an engineer, scientist, educator, technical executive or originator in IEEE-designated fields. The candidate shall have been in professional practice for at least ten years and shall have shown significant performance over a period of at least five of those years.”

To apply, the Senior Member application form is available in 3 formats: Online, downloadable, and electronic version. For more information or to apply for Senior Membership, please see the IEEE Senior Member Program website: http://www.ieee.org/organizations/rab/md/smprogram.html New Senior Members

The following individuals were elevated to Senior Membership Grade thru Nov – Dec:

Larry A. Bergman Adam C. Ward Wai Pang Ng Andre Franzen Junji Yamauchi Luis Ponce George G. King Hongjun Cao Johann P. Reithmaier Wei Li Peter B. Catrysse Norman C. Tien Xiuling Li George C. Chen Xiaoguang Zhang Konstantin L. Vodopyanov Mark Cronin-Golomb

February 2009 IEEE LEOS NEWSLETTER 35 Conference Section

2008 LEOS Awards and Recognitions

John Marsh, LEOS President, recognized the recipients of the 2008 LEOS awards and several of our volunteers for their service to the Society. The awards were presented during the Awards Banquet at the LEOS Annual Meeting in Newport Beach, California, USA.

The IEEE/LEOS William Streifer Scien- The IEEE/LEOS Engineering Achieve- The IEEE/LEOS Distinguished Service tific Achievement Award was presented ment Award was presented to Kent D. Award was presented to James Coleman, to Fumio Koyama, “for contributions to Choquette, “for development of the mono- “for contributions to and leadership in vertical cavity surface emitting semicon- lithic selectively oxidized vertical cavity the area of publications. ductor lasers and dynamic single-mode surface emitting laser.” semiconductor lasers.”

LEOS Fellows

A. Catrina Bryce Han-Ping Shieh LEOS Fellow plaques were presented to A. Catrina Bryce and Han-Ping Shieh in recognition of their achievement to IEEE Fellow grade.

36 IEEE LEOS NEWSLETTER February 2009 Conference Section (cont’d)

Distinguished Lecturers

Massaya Notomi Jorge J. Rocca John Marsh recognized Massaya Notomi and Jorge J. Rocca who completed their terms as LEOS Distinguished Lecturers. Board of Governors

Markus Amann, Carmen Menoni, Kent D. Choquette, and Hideo Kuwahara completed their terms as elected members of the LEOS Board of Governors.

February 2009 IEEE LEOS NEWSLETTER 37 Conference Section (cont’d)

Steve A. Newton Filbert J. Bartoli

Selim Unlu Chennupati Jagadish John recognized Steve A. Newton for his service to LEOS as VP of Finance and Administration, Filbert J. Bartoli for his service as Secretary/Treasurer, Selim Unlu for his service as Associate VP Membership & Regional Activities – Americas, and Chennupati Jagadish for his service as Associate VP Membership & Regional Activities – Asia & Pacific. Chapter Awards

The Chapter of the Year award was presented to the Italy Chapter. The Benelux Student Chapter was awarded the Most Improved Chapter, the award for the Most Innovative Chapter was presented to the Santa Clara Chapter. The award for Largest Membership Increase was presented to the Ukraine Student Chapter, and the Senior Member Initiative Award was presented to the Montreal Chapter. Silvia Maria Pietralunga (Italy), Philippe Tassin (Benelux Student), and Brent Whitlock (Santa Clara Valley), accepted the awards for their chapters.

38 IEEE LEOS NEWSLETTER February 2009 Conference Section (cont’d)

Graduate Student Fellowships

The 2008 IEEE/LEOS Graduate Student Fellowship recipients.

IEEE Awards

William Gruver, IEEE Division X Director, presented the IEEE David Sarnoff Award to James Coleman, “for leadership in the development of highly reliable strained-layer lasers.”, the IEEE Eric E. Sumner Award to Thomas L. Koch, “for pioneering contributions to optoelectronic technologies and their implementation in optical communications systems.”, and IEEE Donald G. Fink Prize Paper Award to Thomas J. Naughton, Bahram Javidi, Osamu Matoba, Yann Frauel, and Enrique Tajahuerce, for their paper entitled, “Three-Dimensional Imaging and Processing Using Computational Holographic Imaging.”

LEOS Staff at the 21st LEOS Annual Meeting in Newport Beach, California, USA.

February 2009 IEEE LEOS NEWSLETTER 39 Conference Section (cont’d)

International Conference on Advanced Optoelectronics and Lasers

The 4th International Conference on Advanced Optoelec- tronics and Lasers (CAOL 2008) was held September 29 – October 4, 2008 in Alushta, on the south coast of Crimea, Ukraine. Alushta is one of the best vacation places in the South Crimea, with a population of about 100,000 and a unique, salubrious climate. Yalta, another nearby famous Crimean city has numerous hotels and cultural attractions and is well known due to the historic Crimean (or Argono- aut) Conference held in Livadia Palace there towards the end of World War II. Among other historical places of Crimea is Bakhchisaray, the former Tatar capital where the famous Palace of the Crimean Khan is located. The 2008 CAOL meeting was organized by the Ukraine LEOS chapter and the Student Chapter at Kharkov National University of Radio Electronics, in cooperation with three Opening session (Speaker: I. Sukhoivanov; Conference co-chairs: Ukrainian Universities: Kharkiv National University of M. Pereira, V.A. Svich, V.A. Maslov, I.V. Dzedolik) Radio Electronics, V. N. Karazin Kharkiv National Univer- sity, and Taurida National V. I. Vernadsky University. Other students. This activity was recognized by made by LEOS organizing chapters include the University of Guanajuato, through several awards, including Most Innovative Chapter Mexico, (Campus Irapuato-Salamanca), the joint IEEE AP/ (2000, 2007), Chapter with Largest Membership Increase MTT/ED/AES/GRS/NPS/EMB East Ukraine Chapter, and (2001, 2002), and Most Improved Chapter (2003). IRE OSA Student Chapter. The large number of organizers We organized 3 meetings in Alushta: 4th Conference has enabled a new series of conferences started in 2002 by “Advanced Optoelectronics and Lasers” (CAOL 2008); 9th the Ukraine LEOS Chapter at the LEOS Chapter Meeting Conference “Laser and Fiber Optical Networks Modeling” in Glasgow. This conference series has resulted in dissemi- (LFNM 2008); and Workshop “Terahertz Radiation: Basic nation of information among researchers in various regions research and application (TERA 2008)”. This set of co- of the world. CAOL has become a recognizable title and the located meetings illustrates the effectiveness of the LEOS conference has attracted contributors from many countries activities in Ukraine and Mexico. Overall, the three meet- in Europe, North America, Australia, and Asia. ings attracted over 200 participants with 230 papers from After the 3rd CAOL in 2006 in Guanajuato, Mexico, 28 countries on five continents. LFNM was the first event cooperation between the Ukraine LEOS Chapter, the Uni- of the LEOS Ukraine Chapter formed in 1998, and today versity of Guanajuato, and LEOS Vice-President Dr. Selim that conference is the annual meeting in Ukraine in the area Ünlü, resulted in formation of a new LEOS Chapter in of laser physics and applied optics. Both LFNM and TERA Guanajuato. This new and active chapter organized the supplement and extend the circle of the participants from “Photonics in Mexico” symposium held in Acapulco on the point of view of the application of theoretical methods July 19-23, 2008 as part of LEOS Summer Topicals 2008. and computer modeling of optoelectronic and laser systems The conference series was continued in Ukraine in 2008. as well as neighboring areas like terahertz technology. The Successful organization of 2008 meetings would not be TERA workshop is unique, because it is devoted to the new possible without permanent interest and support of past and topical area of THz optics and optoelectronics, where LEOS Vice-President Dr. Katya Golovchenko and Summer the combination of fundamental physics and its practical Topicals Chair, LEOS Vice-President Dr. Dominik Rabus. application is used to address the important problems of Dr. Golovchenko played a key role in organizing Photonics anti-terrorism and drug trafficking. in Mexico symposium and has lent invaluable support to Overall, the topics of the conferences embraced physi- the organization of CAOL 2008. cal, mathematical, and technical problems of modern laser In spite of its small number of members, the LEOS physics, photonics, optics and terahertz photonics. Papers Ukraine Chapter is growing and constantly generating new on semiconductor nanoengineering, novel lasers, including ideas directed at encouraging support of Ukraine scien- quantum cascade and quantum dot lasers, photonic crystals tists. Particular attention is given to young scientists and and devices, nonlinear optics, optical measurements, wave

40 IEEE LEOS NEWSLETTER February 2009 Conference Section (cont’d)

Best young speakers. 1st line: Yu. Pilgun (T.Shevchenko National Discussion during the poster session between participants from Univ., Kiev); M. Klimenko (Univ. of Radioelectronics, Khark- Russia, Ukraine, Mexico ov); E. Samsonova (MGU, Moscow), G. Sharma (INRS- EMT, Canada) 2nd line: T. Isaac (University of Exeter, UK); G. Tkachenko propagation and control in lasers and optical systems were (Univ. of Radioelectronics, Kharkov) presented. Other topics included laser radiation control, photonic crystals and devices, ultrabroadband systems, and (who constituted one-third of the participants) were espe- data transmission devices, including those for application cially enjoyed. I would like to make special mention of the in optical computers. The conference proceedings included work of LEOS Student Chapter of the Kharkov National two volumes, one each for CAOL (464 pages) and LFNM University of Radio Electronics, whose members were part (160 pages), and separate CD-ROM proceedings for TERA of the Organizing Committee and not only worked 12 hours workshop. All of conference proceedings were published a day but also made a number of interesting presentations, before the meetings. the high level of which was noted by many participants of During the week, participants had an opportunity to ex- the conference. change ideas during the sessions and in informal discussions Undoubtedly, the most important event of the confer- in the garden of the conference hotel and at the banquet. ence series was participation of LEOS Distinguished Lec- Interaction between well-known scientists and students turer Prof. John O’Brien who gave a seminar on “Photonic

Organizing Committee after conference closing

February 2009 IEEE LEOS NEWSLETTER 41 Conference Section (cont’d)

Crystal Devices”. Other invited speakers included interna- whose topics of interest will be enlarged to cover mid-IR re- tionally known scientists T. M. Benson, University of Not- search http://smmo.org/TERA-MIR2009/. The number of tingham, UK, J. Abbate, Univ. of Naples Federico II Italy, invited speakers already today allows us to hope that TERA- and Prof. Bo Yong, Institute of Physics, Chinese Academy MID Workshop will be one of the primary events in 2009. of Sciences, Beijing, China. Well-known scientific schools We can say with great satisfaction that CAOL and LFNM represented included The University of Leeds, University are first-rate regular English-speaking conferences in the area of Bristol, University of Salford, Sheffield Hallam Univer- of optoelectronics and laser engineering that have obtained sity (U.K.); The Institute of Photonic Sciences and ICREA international recognition. According to participants, CAOL (Spain); , Nonlinear Physics Centre, Australian National is currently the only big conference on laser physics and optics University, Canberra, Australia; R&D Institute of Physics in Ukraine and one of only two big conferences on optics and NAS of Ukraine, Institute of Semiconductors Physics NAS laser physics in the Commonwealth of Independent States. of Ukraine (Ukraine); University of Guanajuato (Mexico), As an organizer, I can say that the future optimal scheme M.V. Lomonosov Moscow State University; Institute of Ap- for this conference series is alternation of separate conferences plied Physics (Russia), National Institute of Materials Sci- like LFNM, TERA, and a wide-topic conference CAOL. For ence, NIMS, Tsukuba, Institute of Science and Technology, this reason, 2009 will be devoted to preparation of TERA- AIST (Japan), and many others. Extremely interesting was MID Workshop in Turkey, and the 10th LFNM conference the talk “Terahertz Quantum Cascade Lasers and Video-Rate is planned for Ukraine in 2010. You are welcome to our THz Imaging” by MIT Prof. Qing Hu. The interest to that meetings! All information about past and future conferences report and following discussions has allowed us to plan of of this series can be found on these and other web sites: the future development of TERA workshop and possible col- http://caol.kture.kharkov.ua/ laborations as well. http://caol.kture.kharkov.ua/eng/lfnm/lfnm_eng.html We were happy to reach agreement on holding the next http://tera2008.kture.kharkov.ua/ terahertz meeting in Turkey after an invitation by Dr. Tu- http://smmo.org/TERA-MIR2009/. grul Hakioglu (Bilkent Universitesi, Ankara, Turkey) who Igor A. Sukhoivanov will represent local organizers. Dr. Tugrul Hakioglu, Prof. Chair of the CAOL/LFNM/TERA Mauro Pereira, and I are actively preparing that workshop joint Organizing Committees

Visit the LEOS web site for more information: www.i-LEOS.org

42 IEEE LEOS NEWSLETTER February 2009 Conference Section (cont’d)

February 2009 IEEE LEOS NEWSLETTER 43 Conference Section (cont’d)

44 IEEE LEOS NEWSLETTER February 2009 Conference Section (cont’d)

February 2009 IEEE LEOS NEWSLETTER 45 Conference Section (cont’d)

46 IEEE LEOS NEWSLETTER February 2009 Publication Section

Call for Papers

Announcing an Issue of the IEEE JOURNAL Online Submission is Mandatory at: http://mc.manu- OF SELECTED TOPICS IN QUANTUM scriptcentral.com/leos-ieee. Please select the Journal of ELECTRONICS on Metamaterials Selected Topics Of Quantum Electronics Journal from the Submission Deadline: June 5, 2009 drop down menu. IEEE Journal of Selected Topics in Quantum Elec- tronics invites manuscript submissions in the area of For inquiries please contact: metamaterials, transformation optics and applications. Chin Tan-yan Electromagnetic metamaterials is a rapidly developing IEEE/LEOS Publications Coordinator field with remarkable potential for enabling new ways of 445 Hoes Lane, Piscataway, NJ 08854 USA controlling light from macro- to nano-scale. The purpose Phone: 732-465-5813, Email: [email protected] of this issue of JSTQE is to highlight the recent progress and trends in design, modeling, fabrication and applica- For all papers published in JSTQE, there are voluntary tions of metamaterials. Broad technical areas include (but page charges of $110.00 per page for each page up to eight are not limited to): pages. Invited papers can be twelve pages and Contributed • Novel metamaterials designs papers should be 8 pages in length before overlength page • Low-loss metamaterials: new approaches and charges of $220.00 per page are levied. The length of each fabrication techniques paper is estimated when it is received. Authors of papers • Modeling and optimization tools that appear to be overlength are notified and given the op- • Broadband and tunable metamaterials tion to shorten the paper. Additional charges will apply if • Optical nanocircuits color figures are required. • Light manipulation via transformation optics • Cloaking The following supporting documents are required during • Light concentrators and electromagnetic field manuscript submission: enhancement with metamaterials • Positive, negative, and near-zero guided wave structures 1) .doc manuscript (double columned, 12 pages for an • Super- and Hyper-lenses Invited Paper. Contributed paper should be double • Novel applications columned, 8 pages in length.) Bios of ALL authors are mandatory, photos are optional. You may find The Guest Editors for this issue are Vladimir Shalaev, the Tools for Authors link useful: http://www.ieee. Purdue University, USA; Natalia Litchinitser, State org/web/publications/authors/transjnl/index.html University of New York at Buffalo, USA; Thomas 2) Completed the IEEE Copyright Form. Copy and Klar, Technical University of Ilmenau, Germany; Na- paste the link below: http://www.ieee.org/web/ der Engheta, University of Pennsylvania, USA, Ross publications/rights/copyrightmain.html McPhedran, University of Sydney, Australia, Ekaterina 3) Completed Color Agreement/decline form.. (Please Shamonina, University of Erlangen-Nuremberg, email [email protected] to request for this form.) Germany. 4) .doc list of ALL Authors FULL Contact information as stated below: Last name (Family name): /First The deadline for submission of manuscripts is June 5, name: Suffix (Dr/Prof./Ms./Mr):/Affiliation:/Dept:/ 2009; publication is scheduled for March/April of 2010. Address:/Telephone:/Fax:/Email:/Alternative Email:

February 2009 IEEE LEOS NEWSLETTER 47 ADVERTISER’S INDEX The Advertiser’s Index contained in this issue is IEEE Lasers and Electro-Optics compiled as a service to our readers and advertisers. The publisher is not liable for errors or omis- sions although every effort is made to ensure its Society Newsletter accuracy. Be sure to let our advertisers know you Advertising Sales Offices found them through the IEEE LEOS Newsletter. 445 Hoes Lane, Piscataway NJ 08854 Advertiser Page # www.ieee.org/ieeemedia R Soft ...... CVR2 Impact this hard-to-reach audience in their own Society publication. For further information on product and California Scientific, Inc...... 20 recruitment advertising, call your local sales office. Optimax Systems, Inc...... 24 MANAGEMENT Midwest/ New England/ Tempo Plastic Company...... 25 James A. Vick Ontario, Canada Eastern Canada Staff Director, Advertising Will Hamilton John Restchack Third Millennium Engineering . . . . 25 Phone: 212-419-7767 Phone: 269-381-2156 Phone: 212-419-7578 Fax: 212-419-7589 Fax: 269-381-2556 Fax: 212-419-7589 [email protected] Optiwave Systems Inc ...... 33 [email protected] [email protected] IN, MI. Canada: Ontario ME, VT, NH, MA, RI Susan E. Schneiderman Canada: Quebec, General Photonics...... CVR4 Business Development Northwest/Northern Nova Scotia, Manager Prince Edward Island, Phone: 732-562-3946 California/Southwest Newfoundland, Fax: 732-981-1855 Shaun Mehr New Brunswick [email protected] Phone: 949-923-1660 LEOS Mission Statement Fax: 775-908-2104 LEOS shall advance the interests of its mem- Marion Delaney [email protected] Southeast Advertising Sales Director Thomas Flynn bers and the laser, optoelectronics, and photo- AR, LA, OK, TX, AK, ID, Phone: 415-863-4717 MT, WY, OR, WA, CA Phone: 770-645-2944 Fax: 415-863-4717 nics professional community by: 93401 & above Fax: 770-993-4423 [email protected] • providing opportunities for information Canada: British Columbia [email protected] exchange, continuing education, and VA, NC, SC, GA, FL, AL, PRODUCT MS, TN professional growth; ADVERTISING So. California/ • publishing journals, sponsoring confer- Midatlantic Mountain States ences, and supporting local chapter and Lisa Rinaldo Marshall Rubin Midwest/Texas/ Central Canada student activities; Phone: 732-772-0160 Phone: 818-888-2407 Fax: 732-772-0161 Fax: 818-888-4907 Darcy Giovingo • formally recognizing the professional [email protected] [email protected] Phone: 847-498-4520 contributions of members; NY, NJ, PA, DE, MD, DC, HI, AZ, NM, CO, UT, Fax: 847-498-5911 • representing the laser, optoelectronics, KY, WV NV, CA 93400 & below [email protected]; and photonics community and serving as AR, IL, IN, IA, KS, LA, New England/ MI, MN, MO, NE, ND, Europe/Africa/ its advocate within the IEEE, the broader Eastern Canada SD, OH, Middle East scientific and technical community, and Jody Estabrook OK, TX, WI. Heleen Vodegel society at large. Phone: 774-283-4528 Canada: Ontario, Phone: +44-1875-825-700 Fax: 774-283-4527 Manitoba, Saskatchewan, [email protected] Fax: +44-1875-825-701 Alberta LEOS Field of Interest ME, VT, NH, MA, RI, CT [email protected] The Field of Interest of the Society shall be Canada: Quebec, Nova Scotia, Europe, Africa, Middle East Newfoundland, Prince Edward West Coast/Southwest/ lasers, optical devices, optical fibers, and asso- Mountain States Island, New Brunswick Asia/Far East/ ciated lightwave technology and their appli- Tim Matteson Pacific Rim cations in systems and subsystems in which Southeast Phone: 310-836-4064 Susan Schneiderman quantum electronic devices are key elements. Thomas Flynn Fax: 310-836-4067 Phone: 732-562-3946 Phone: 770-645-2944 [email protected] The Society is concerned with the research, Fax: 732-981-1855 development, design, manufacture, and ap- Fax: 770-993-4423 AZ, CO, HI, NV, NM, [email protected] [email protected] UT, CA, AK, ID, MT, plications of materials, devices and systems, VA, NC, SC, GA, FL, AL, Asia, Far East, Pacific Rim, WY, OR, WA. and with the various scientific and technolog- MS, TN Australia, New Zealand Canada: British Columbia ical activities which contribute to the useful expansion of the field of quantum electronics Midwest/Central Canada RECRUITMENT Dave Jones ADVERTISING Europe/Africa/ and applications. Phone: 708-442-5633 Midatlantic Middle East The Society shall aid in promoting close Fax: 708-442-7620 Lisa Rinaldo Heleen Vodegel cooperation with other IEEE groups and [email protected] Phone: 732-772-0160 Phone: +44-1875-825-700 societies in the form of joint publications, IL, IA, KS, MN, MO, NE, Fax: 732-772-0161 Fax: +44-1875-825-701 [email protected] sponsorship of meetings, and other forms of ND, SD, WI, OH [email protected] Canada: Manitoba, NY, NJ, CT, PA, DE, MD, Europe, Africa, information exchange. Appropriate coopera- Saskatchewan, Alberta DC, KY, WV Middle East tive efforts will also be undertaken with non- IEEE societies.

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