DOCSLIB.ORG

Silicon Photonics: Waveguide Modulators and Detectors

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Silicon Photonics: Waveguide Modulators and Detectors 2572-11 Winter College on Optics: Fundamentals of Photonics - Theory, Devices and Applications 10 - 21 February 2014 Silicon photonics: Waveguide modulators and detectors Laurent Vivien Institut dElectronique Fondamentale CNRS UMR 8622 Université Paris Sud, 91405 Orsay Cedex France Silicon Photonics Silicon-based micro and nanophotonic devices Silicon photonics: Waveguide modulators and detectors Laurent Vivien Institut d’Electronique Fondamentale, CNRS UMR 8622, Université Paris Sud, 91405 Orsay Cedex, France http://silicon-photonics.ief.u-psud.fr/ http://silicon-photonics.ief.u-psud.fr/ 1 Silicon Photonics Silicon-based micro and nanophotonic devices Silicon photonics: Waveguide modulators and detectors L. Vivien, D. Marris-Morini, G. Rasigade, L. Virot, M. Ziebell, D. Perez-Galacho, P. Chaisakul, M-S. Rouifed, P. Crozat, P. Damas, E. Cassan D. Bouville, S. Edmond, X. Le Roux Institut d’Electronique Fondamentale, CNRS UMR 8622, Université Paris Sud, 91405 Orsay Cedex, France http://silicon-photonics.ief.u-psud.fr/ J-M. Fédéli, S, Olivier, Jean Michel Hartmann CEA-LETI, Minatec 17 rue des Martyrs, 38054 Grenoble cedex 9, France G. Isella, D. Chrastina, J. Frigerio L-NESS, Politecnico di Milano, Polo di Como, Via Anzani 42, I-22100 Como, Italy C. Baudot, F. Boeuf STMicroelectronics, Silicon Technology Development, Crolles, France http://silicon-photonics.ief.u-psud.fr/ 2 The Institute for Fundamental Electronics IEF is a joint research unit between CNRS and University of Paris Sud 135 CNRS researchers, professors and lecturers, technical staff +100 PhD students, Post-Doc and visitors ~ 400 students undergoing training within IEF's ground Spintronics and Si-based Nano-electronics Micro-Nano systems and systems Photonics University Technology Center (CTU) MINERVE http://silicon-photonics.ief.u-psud.fr/ 3 Laurent Vivien University Technology Center IEF-MINERVE member of The French Network on “Basic Technological Research” (RTB) University Technology Centre (1000 m²): Photolithography: 2-sided UV lithography with wafer bonding Deep UV lithography (248 nm) 2 e-beams (Raith150 and 100keV nanobeam) Laser Etching: Wet etching (KOH, TMAH, …) Dry etching : fluoride gases RIE (2 systems) ICP Si deep etching IBE 02 plasma etching Chloride gases RIE … http://silicon-photonics.ief.u-psud.fr/ 4 Laurent Vivien Silicon photonics group 4 permanent Researchers 2 engineers, technicians 16 PhD students 2 post-doc 2-4 master students / year Passive devices CEA / LETI Strained Si photonics Grating couplers Pockels effect Waveguides Splitters Optical Distribution Multi-wavelength circuits Ge detectors Photonic crystals Ge-SiGe QW photonics Surface illuminated Optical modulators Slow light Source Integrated All silicon Superprism Modulator NL materials APD NL enhancement detector Ge QW Plasmon CEA / LETI Bottom contact Top contact Ge 3 µm 40 GBit/s Carbon nanotubes for photonics 300 nm http://silicon-photonics.ief.u-psud.fr/ 5 Laurent Vivien Outline Motivation (Pavel’s and Lorenzo’s talks) Photodetectors on silicon Main characteristics Results Optical modulators Figures of Merit Modulation in silicon Results Conclusion http://silicon-photonics.ief.u-psud.fr/ 6 Laurent Vivien FTTH Optical telecommunications Environment Data centers Silicon photonics Chemical/Biological sensors Interconnects Free space communications Military Silicon photonic building blocks Off‐chip III‐V laser On‐chip III‐V laser on Si photodetector RF electrodes Optical coupler Input waveguide Germanium‐based laser 10 µm Emitter Receiver Laser Modulator Detector Modulator http://silicon-photonics.ief.u-psud.fr/ 8 Laurent Vivien Photodetection http://silicon-photonics.ief.u-psud.fr/ 9 Laurent Vivien Basic principle Main characteristic of the material? h e- h+ - h+ e -+ http://silicon-photonics.ief.u-psud.fr/ 10 Laurent Vivien Basic principle The aborption of photons generates electron-hole pairs Photogenerated carriers are then collected thanks to an external field Photocurrent h e- h+ - h+ e -+ http://silicon-photonics.ief.u-psud.fr/ 11 Laurent Vivien Absorption mechanisms (II) Direct gap SC (III-V SC) Indirect gap SC (IV-IV SC) E k Phonon emission h Phonon absorption k absorbed photons generate free electron-hole pairs EG=hc/G G G http://silicon-photonics.ief.u-psud.fr/ 12 Laurent Vivien Material choice Wavelength ranges: 1.3 µm – 1.6 µm 0.85 µm Direct bandgap http://silicon-photonics.ief.u-psud.fr/ 13 Laurent Vivien Material choice Wavelength ranges: 1.3 µm – 1.6 µm 0.85 µm Indirect bandgap http://silicon-photonics.ief.u-psud.fr/ 14 Laurent Vivien Material choice Wavelength ranges: 1.3 µm – 1.6 µm 0.85 µm Two choices: InGaAs or Ge Indirect bandgap Direct gap absorption http://silicon-photonics.ief.u-psud.fr/ 15 Laurent Vivien Material choice InGaAs versus Germanium What is the best material for light detection in near-IR wavelength range ? http://silicon-photonics.ief.u-psud.fr/ 16 Laurent Vivien Material choice versus electronic photonic integration scheme •Use of standard FE CMOS technologies Photonic layer at the 1) Wafer bonding of •High integration density last levels of PIC (high T°C) (AboveIC) metallizations •Multilevel process with back-end 2) BE fab(<400°C) capability fabrication •Specific FE CMOS technology and library Combined •Flip-Chip hybridization of InP components front-end fabrication •Moderate integration density •Efficient connections of EIC and PIC 1) Wafer bonding of •Through substrate Backside PIC (high T°C) fabrication connections •High integration density BE: Back end FE:Front end 2) BE fab(<400°C) http://silicon-photonics.ief.u-psud.fr/ 17 Laurent Vivien Material choice versus integration scheme Ge or Photonic InGaAs layer at the 1) Wafer bonding of last levels of PIC (high T°C) metallizations with back-end 2) BE fab(<400°C) fabrication InGaAs Combined front-end Ge fabrication Ge or 1) Wafer bonding of InGaAs Backside PIC (high T°C) fabrication BE: Back end FE:Front end 2) BE fab(<400°C) InGaAs http://silicon-photonics.ief.u-psud.fr/ 18 Laurent Vivien Are III-V materials integrated in silicon platform? Monolithic integration via epitaxial growth No viable solutions yet Hybrid integration BCB or molecular bonding http://silicon-photonics.ief.u-psud.fr/ 19 Laurent Vivien Exemple of hybrid integration 1. Sample preparation 2. Sample cleaning + removal of cap layer 3. BCB bonding and curing 4. InP substrate removal 5. Removal of sacrificial layers 6. Detector mesa etching III-V materials can be integrated on silicon 7. BCB insulation What about wafer size and technology? 8. Opening of the contact windows 9. Metallization 10. Post-processing http://silicon-photonics.ief.u-psud.fr/ 20 Laurent Vivien Germanium on silicon: Pros and Cons Absorption coefficient of pure Ge: 9000 cm-1 at =1.3µm 95% LABS 3.3µm (!) Low capacitance devices High frequency operation High carrier mobility http://silicon-photonics.ief.u-psud.fr/ 21 Laurent Vivien Crystal lattice structure of Silicon and Germanium Si and Ge have a diamond lattice structure (two interdigitated FCC lattices) Properties Silicon Germanium Lattice parameter: 5.431 5.658 a (Å) Atomic density (cm-3) 5,0.1022 4,42.1022 Atom radius (Å) 0.117 0,122 Lattice structure Diamond Diamond Lattice parameter mismatch: ~4.2 % http://silicon-photonics.ief.u-psud.fr/ 22 Laurent Vivien Germanium on silicon: Pros and Cons Absorption coefficient of pure Ge: Lattice misfit with Si of about 4.2% 9000 cm-1 at =1.3µm specific growth strategies 95% LABS 3.3µm (!) required (wafer-scale and Low capacitance devices localized) High frequency operation Low indirect bandgap: EG=0.66eV High carrier mobility high dark current for MSM devices Can we directly growth Ge on silicon? http://silicon-photonics.ief.u-psud.fr/ 23 Laurent Vivien The lattice mismatch 4.2% of lattice mismatch between germanium and silicon Ge quantum dots QD, QW or Bulk ? Si1-xGex/Si quantum wells Pure Ge on Si SiGe on Si http://silicon-photonics.ief.u-psud.fr/ Laurent Vivien Ge-based structures Ge quantum dots ~20cm-1 (90% absorption length ~ 1.1mm) Si1-xGex/Si quantum wells ~100-200cm-1 (90% absorption length ~ 230-110µm) Pure Ge on Si ~7500cm-1 (90% absorption length ~ 3µm) http://silicon-photonics.ief.u-psud.fr/ Laurent Vivien Ge growth strategies Thick virtual SiGe substrates (10µm) Need for a new integration scheme – difficult to integrate with SOI waveguides. Ge SiGe buffer graded from Si to Ge Si(100) http://silicon-photonics.ief.u-psud.fr/ 26 Laurent Vivien Ge growth strategies Thick virtual SiGe substrates (10µm) Need for a new integration scheme – difficult to integrate with SOI waveguides. Growth on thin SiGe buffers The thickness of the thin SiGe buffer is around 1µm Always too thick for integration with SOI Ge SiGe buffer graded from Si to Ge Si(100) http://silicon-photonics.ief.u-psud.fr/ 27 Laurent Vivien Ge growth strategies Thick virtual SiGe substrates (10µm) Need for a new integration scheme – difficult to integrate with SOI waveguides. Growth on thin SiGe buffers The thickness of the thin SiGe buffer is around 1µm Always too thick for integration with SOI Direct Ge growth on Si Ge Si(100) http://silicon-photonics.ief.u-psud.fr/ 28 Laurent Vivien Germanium growth Two-step growth process: Direct growth of Ge on Si using a low temperature (350°) CVD process thin (a few 10nm) highly-dislocated Ge layer Growth of a thick Ge layer (a few 100nm) at a higher temperature (600°) high quality Ge absorbing layer Thermal annealing to reduce the dislocation density HT Ge (600°C,
Load more

Recommended publications
  • Lecture 17 - Rectangular Waveguides/Photonic Crystals� and Radiative Recombination -Outline�
    6.772/SMA5111 - Compound Semiconductors Lecture 17 - Rectangular Waveguides/Photonic Crystals� and Radiative Recombination -Outline� • Dielectric optics (continuing discussion in Lecture 16) Rectangular waveguides� Coupled rectangular waveguide structures Couplers, Filters, Switches • Photonic crystals History: Optical bandgaps and Eli Yablonovich, to the present One-dimensional photonic crystals� Distributed Bragg reflectors� Photonic fibers; perfect mirrors� Two-dimensional photonic crystals� Guided wave optics structures� Defect levels� Three-dimensional photonic crystals • Recombination Processes (preparation for LEDs and LDs) Radiative vs. non-radiative� Relative carrier lifetimes� C. G. Fonstad, 4/03 Lecture 17 - Slide 1 Absorption in semiconductors - indirect-gap band-to-band� •� The phonon modes involved indirect band gap absorption •� Dispersion curves for acoustic and optical phonons Approximate optical phonon energies for several semiconductors Ge: 37 meV (Swaminathan and Macrander) Si: 63 meV GaAs: 36 meV C. G. Fonstad, 4/03� Lecture 15 - Slide 2� Slab dielectric waveguides� •�Nature of TE-modes (E-field has only a y-component). For the j-th mode of the slab, the electric field is given by: - (b -w ) = j j z t E y, j X j (x)Re[ e ] In this equation: w: frequency/energy of the light pw = n = l 2 c o l o: free space wavelength� b j: propagation constant of the j-th mode Xj(x): mode profile normal to the slab. satisfies d 2 X j + 2 2- b 2 = 2 (ni ko j )X j 0 dx where:� ni: refractive index in region i� ko: propagation constant in free space = pl ko 2 o C. G. Fonstad, 4/03� Lecture 17 - Slide 3� Slab dielectric waveguides� •�In approaching a slab waveguide problem, we typically take the dimensions and indices in the various regions and the free space wavelength or frequency of the light as the "givens" and the unknown is b, the propagation constant in the slab.
    [Show full text]
  • Lecture 26 Dielectric Slab Waveguides
    Lecture 26 Dielectric Slab Waveguides In this lecture you will learn: • Dielectric slab waveguides •TE and TM guided modes in dielectric slab waveguides ECE 303 – Fall 2005 – Farhan Rana – Cornell University TE Guided Modes in Parallel-Plate Metal Waveguides r E()rr = yˆ E sin()k x e− j kz z x>0 o x x Ei Ei r r Ey k E r k i r kr i H Hi i z ε µo Hr r r ki = −kx xˆ + kzzˆ kr = kx xˆ + kzzˆ Guided TE modes are TE-waves bouncing back and fourth between two metal plates and propagating in the z-direction ! The x-component of the wavevector can have only discrete values – its quantized m π k = where : m = 1, 2, 3, x d KK ECE 303 – Fall 2005 – Farhan Rana – Cornell University 1 Dielectric Waveguides - I Consider TE-wave undergoing total internal reflection: E i x ε1 µo r k E r i r kr H θ θ i i i z r H r ki = −kx xˆ + kzzˆ r kr = kx xˆ + kzzˆ Evanescent wave ε2 µo ε1 > ε2 r E()rr = yˆ E e− j ()−kx x +kz z + yˆ ΓE e− j (k x x +kz z) 2 2 2 x>0 i i kz + kx = ω µo ε1 Γ = 1 when θi > θc When θ i > θ c : kx = − jα x r E()rr = yˆ T E e− j kz z e−α x x 2 2 2 x<0 i kz − α x = ω µo ε2 ECE 303 – Fall 2005 – Farhan Rana – Cornell University Dielectric Waveguides - II x ε2 µo Evanescent wave cladding Ei E ε1 µo r i r k E r k i r kr i core Hi θi θi Hi ε1 > ε2 z Hr cladding Evanescent wave ε2 µo One can have a guided wave that is bouncing between two dielectric interfaces due to total internal reflection and moving in the z-direction ECE 303 – Fall 2005 – Farhan Rana – Cornell University 2 Dielectric Slab Waveguides W 2d Assumption: W >> d x cladding y core
    [Show full text]
  • High-Index Glass Waveguides for AR Roadmap to Consumer Market
    High-Index Glass Waveguides for AR Roadmap to Consumer Market Dr. Xavier Lafosse Commercial Technology Director, Advanced Optics SPIE AR / VR / MR Conference February 2-4, 2020 Outline • Enabling the Display Industry Through Glass Innovations • Our Solutions for Augmented Reality Applications • The Challenges for Scalable and Cost-Effective Solutions Precision Glass Solutions © 2020 Corning Incorporated 2 Corning’s glass innovations have enabled displays for more than 80 years… 1939 1982 2019 Cathode ray tubes for Liquid crystal display (LCD) EAGLE XG® Glass is the black and white televisions glass for monitors, laptops LCD industry standard Precision Glass Solutions © 2020 Corning Incorporated 3 Corning is a world-renowned innovator and supplier across the display industry Cover Glass Glass For AR/MR Display for Display Waveguides Display Technologies Introduced glass panels for 1st active 12 years of innovation in cover Corning Precision Glass Solutions matrix LCD devices in 1980s glass for smartphones, laptops, (PGS) was the first to market with tablets & wearables ultra-flat, high-index wafers for top- Have sold 25 billion square feet of tier consumer electronic companies ® ® ® ® flagship Corning EAGLE XG Corning Gorilla Glass is now on pursuing augmented reality and more than 7 billion devices worldwide mixed reality waveguide displays Precision Glass Solutions © 2020 Corning Incorporated 4 PGS offers best-in-class glass substrates for semiconductor and consumer electronics applications Advanced Low-loss, low Wafer-level Waveguide
    [Show full text]
  • University of California Santa Cruz Distributed Bragg
    UNIVERSITY OF CALIFORNIA SANTA CRUZ DISTRIBUTED BRAGG REFLECTOR ON ARROW WAVEGUIDES A thesis submitted in partial satisfaction of the requirements for the degree of BACHELOR OF SCIENCE in PHYSICS by Raul A. Reyes Hueros June 2018 The thesis of Raul A. Reyes Hueros is approved: Professor Robert P. Johnson, Chair Professor Holger Schmidt Professor David Smith Copyright c by Raul A. Reyes Hueros 2018 Abstract Distributed Bragg Reflector on ARROW Waveguides by Raul A. Reyes Hueros A new optofluidic chip design for an on-chip liquid dye laser based on Anti- Resonant Reflecting Optical Waveguides (ARROW) is developed. The microfluidic device is compact, user friendly and, most importantly, can provide the role of a on chip laser. This thesis can be broken into three parts: First, an analysis on distributive feed back (DFB) gratings that is developed to fabricate a optofluidic dye laser from anti-resonant reflecting optical waveguides (ARROW). Second, the reflection spectrum and plausible parameters for the proposed device are simulated with Roaurd's Method. Third, a technique for direct dry transfer of uniform poly (methyl methacrylate) (PMMA) is used to overcome the challenges encountered in conventional PMMA deposition on top of non-flat waveguide structures. Table of Contents Abstract iii List of Figures vi List of Tables viii Acknowledgments ix 1 Introduction 1 1.1 Motivations for Building On-chip Bragg Reflector . 2 1.2 Thesis Organization . 3 2 Background 4 2.1 Distributed Bragg Reflector Gratings . 4 2.2 Organic Dye Molecules . 7 2.2.1 Population Inversion . 7 2.3 Liquid Dye Laser . 9 3 Anti-Resonant Reflecting Optical Waveguides 12 3.1 Theory .
    [Show full text]
  • Waveguide Propagation
    NTNU Institutt for elektronikk og telekommunikasjon Januar 2006 Waveguide propagation Helge Engan Contents 1 Introduction ........................................................................................................................ 2 2 Propagation in waveguides, general relations .................................................................... 2 2.1 TEM waves ................................................................................................................ 7 2.2 TE waves .................................................................................................................... 9 2.3 TM waves ................................................................................................................. 14 3 TE modes in metallic waveguides ................................................................................... 14 3.1 TE modes in a parallel-plate waveguide .................................................................. 14 3.1.1 Mathematical analysis ...................................................................................... 15 3.1.2 Physical interpretation ..................................................................................... 17 3.1.3 Velocities ......................................................................................................... 19 3.1.4 Fields ................................................................................................................ 21 3.2 TE modes in rectangular waveguides .....................................................................
    [Show full text]
  • Ultra-Low-Loss Silicon Waveguides for Heterogeneously Integrated Silicon/III-V Photonics
    applied sciences Article Ultra-Low-Loss Silicon Waveguides for Heterogeneously Integrated Silicon/III-V Photonics Minh A. Tran *, Duanni Huang, Tin Komljenovic, Jonathan Peters, Aditya Malik and John E. Bowers ID Department of Electrical and Computer Engineering, University of California at Santa Barbara, Santa Barbara, CA 93106, USA; [email protected] (D.H.); [email protected] (T.K.); [email protected] (J.P.); [email protected] (A.M.); [email protected] (J.E.B.) * Correspondence: [email protected]; Tel.: +1-805-893-2149 Received: 16 June 2018; Accepted: 9 July 2018; Published: 13 July 2018 Featured Application: Ultra-low-loss Si waveguide platform for heterogeneous integration with III/V. Abstract: Integrated ultra-low-loss waveguides are highly desired for integrated photonics to enable applications that require long delay lines, high-Q resonators, narrow filters, etc. Here, we present an ultra-low-loss silicon waveguide on 500 nm thick Silicon-On-Insulator (SOI) platform. Meter-scale delay lines, million-Q resonators and tens of picometer bandwidth grating filters are experimentally demonstrated. We design a low-loss low-reflection taper to seamlessly integrate the ultra-low-loss waveguide with standard heterogeneous Si/III-V integrated photonics platform to allow realization of high-performance photonic devices such as ultra-low-noise lasers and optical gyroscopes. Keywords: ultra-low-loss waveguide; silicon photonics; heterogeneous integration; narrow linewidth lasers; high Q resonators 1. Introduction Photonic integration promises significant improvement in performance, reliability and SWaP-C (size, weight, power and cost) due to integration of components, reduced coupling losses and reduced sensitivity to environmental perturbation.
    [Show full text]
  • Planar Transmission Lines
    Adapted from notes by ECE 5317-6351 Prof. Jeffery T. Williams Microwave Engineering Fall 2018 Prof. David R. Jackson Dept. of ECE Notes 11 Waveguiding Structures Part 6: Planar Transmission Lines w ε0 ε r h 1 Planar Transmission Lines w w b ε h r εr Microstrip Stripline w w εr g g h εr g g h Coplanar Waveguide (CPW) Conductor-backed CPW s s εr h εr h Slotline Conductor-backed Slotline 2 Planar Transmission Lines (cont.) w w w w ε h εr s h r s Coplanar Strips (CPS) Conductor-backed CPS . Stripline is a planar version of coax. Coplanar strips (CPS) is a planar version of twin lead. 3 Stripline . Common on circuit boards ε,, µσd b . Fabricated with two circuit boards w . Homogenous dielectric (perfect TEM mode) TEM mode (also TE & TM Modes) Field structure for TEM mode: Electric Field Magnetic Field 4 Stripline (cont.) . Analysis of stripline is not simple. TEM mode fields can be obtained from an electrostatic analysis (e.g., conformal mapping). A closed stripline structure is analyzed in the Pozar book by using an approximate numerical method: b w b /2 ε,, µσd a ab>> 5 Stripline (cont.) Conformal mapping solution (S. Cohn): Exact solution: 30π Kk ( ) Z0 = K = complete elliptic Kk()′ integral of the first kind π /2 1 Kk( ) ≡ dθ ∫ 22 0 1− k sin θ π w k = sech 2b π w k′ = tanh 2b 6 Stripline (cont.) Curve fitting this exact solution: η b Z = 0 ln( 4) 0 ε ln(4) Note : = 0.441 4 r wb+ π e π Effective width Fringing term w 0 ;for ≥ 0.35 wwe b = − 2 bbww 0.35− ;for 0.1≤≤ 0.35 bb 1bb /2 η η b ideal 0 The factor of 1/2 in front is from the parallel Note: Z0 =η = = 24ww4w ε r combination of two ideal PPWs.
    [Show full text]
  • Silicon Nitride in Silicon Photonics
    Silicon Nitride in Silicon Photonics By DANIEL J. BLUMENTHAL , Fellow IEEE,RENÉ HEIDEMAN,DOUWE GEUZEBROEK,ARNE LEINSE, AND CHRIS ROELOFFZEN | ABSTRACT The silicon nitride (Si3N4) planar waveguide plat- history of low-loss Si3N4 waveguide technology and a survey of form has enabled a broad class of low-loss planar-integrated worldwide research in a variety of device and applications as devices and chip-scale solutions that benefit from trans- well as the status of Si3N4 foundries. parency over a wide wavelength range (400–2350 nm) and KEYWORDS | Biophotonics; lasers; microwave photonics; fabrication using wafer-scale processes. As a complimentary optical device fabrication; optical fiber devices; optical fil- platform to silicon-on-insulator (SOI) and III–V photonics, Si N 3 4 ters; optical resonators; optical sensors; optical waveguides; waveguide technology opens up a new generation of system- photonic-integrated circuits; quantum entanglement; silicon on-chip applications not achievable with the other platforms nitride; silicon photonics; spectroscopy alone. The availability of low-loss waveguides (<1dB/m)that can handle high optical power can be engineered for linear and nonlinear optical functions, and that support a variety of pas- I. INTRODUCTION sive and active building blocks opens new avenues for system- Photonic-integrated circuits (PICs) are poised to enable an on-chip implementations. As signal bandwidth and data rates increasing number of applications including data commu- continue to increase, the optical circuit functions and com- nications and telecommunications [1], [2], biosensing [3], plexity made possible with Si3N4 has expanded the practical positioning and navigation [4], low noise microwave application of optical signal processing functions that can synthesizers [5], spectroscopy [6], radio-frequency (RF) reduce energy consumption, size and cost over today’s digital signal processing [7], quantum communication [8], and electronic solutions.
    [Show full text]
  • Hollow Silica Waveguide Usage Guide and Test Process Overview
    Hollow Silica Waveguide Usage Guide and Test Process Overview Introduction The Hollow Silica Waveguide (HSW) built and marketed by Polymicro Technologies is designed to deliver infrared power in a flexible and rugged package from below 2.9 microns up to 20 microns, a region where silica fibers are far too glossy for practical operation. The waveguides consist of a fused silica capillary tube with an optically reflective internal silver halide coating. For protection, the capillary tube is coated with an external jacket of acrylate, which improves the strength and flexibility of the waveguide. Because typical silica-based fibers heavily absorb light with wavelengths above 1.9 microns, a different technology is required. The Hollow Silica Waveguide is a good solution for mid to far infrared applications, such as power delivery for CO2 and Erbium YAG lasers, and spectroscopy making use of the unique hollow structure. Polymicro Technologies’ waveguides have been optimized for low optical power loss operation at either CO2 (10.6 µm) or Er:YAG (2.94 µm) wavelengths, although relatively low loss operation is possible in the intervening wavelength band. These waveguides are available with internal bore sizes of 300, 500, 750, and 1000 microns. They can also be built into custom assemblies with protective outer jackets and connectors. While these waveguides have similarities with normal optical fibers, significant differences exist which require different handling and operation techniques. This note has been written to discuss the processes needed to work with these waveguides, with an additional section outlining the methods and conditions used to test their optical performance prior to shipment here at Polymicro.
    [Show full text]
  • Chapter 8 Waveguides and Resonators
    Chapter 8 Waveguides and Resonators The objective of resonators is to confine electromagnetic energy. On the other hand, the purpose of waveguides is to guide electromagnetic energy. In both cases, the desired functionality is achieved through material boundaries. 8.1 Resonators Let us consider a rectangular box with sides Lx, Ly,andLz,asshowninFig.8.1. The interior of the box is filled with a linear and isotropic material characterized by ε and µ.Thewallsoftheboxareperfectlyreflecting,thatis,thefields are not able to penetrate into the walls. Furthermore, there are no sources present, which implies that we’re looking for homogeneous solutions of the wave equation, that is, solutions of the Helmholtz equation (3.15). To solve the Helmholtz equation for the x component of the complex electric field vector E we write (x) Ex(x, y, z)=E0 X(x) Y (y) Z(z) , (8.1) which is referred to as separation of variables. X, Y ,andZ are dimensionless functions and E(x) is a constant field amplitude. Inserting into [ 2 + k2]E =0 0 ∇ x yields 1 ∂2X 1 ∂2Y 1 ∂2Z + + + k2 =0. (8.2) X ∂x2 Y ∂y2 Z ∂z2 117 118 CHAPTER 8. WAVEGUIDES AND RESONATORS In order for this equation to hold for any x, y,andz we have to require that each of the terms is constant. We set these constants to be k2, k2 and k2,which − x − y − z implies ω2 k2 + k2 + k2 = k2 = n2(ω) . (8.3) x y z c2 We obtain three separate equations for X, Y ,andZ 2 2 2 ∂ X/∂x + kxX =0 2 2 2 ∂ Y/∂y + kyY =0 2 2 2 ∂ Z/∂z + kz Z =0, (8.4) with the solutions exp[ ik x], exp[ ik y],andexp[ ik z].Thus,thesolutionsfor ± x ± y ± z Ex become (x) −ikxx ikxx −ikyy ikyy −ikzz ikzz Ex(x, y, z)=E0 [c1,x e + c2,x e ][c3,x e + c4,x e ][c5,x e + c6,x e ] .
    [Show full text]
  • Resonant Cavities and Waveguides
    Resonant Cavities and Waveguides 12 Resonant Cavities and Waveguides This chapter initiates our study of resonant accelerators., The category includes rf (radio-frequency) linear accelerators, cyclotrons, microtrons, and synchrotrons. Resonant accelerators have the following features in common: 1. Applied electric fields are harmonic. The continuous wave (CW) approximation is valid; a frequency-domain analysis is the most convenient to use. In some accelerators, the frequency of the accelerating field changes over the acceleration cycle; these changes are always slow compared to the oscillation period. 2. The longitudinal motion of accelerated particles is closely coupled to accelerating field variations. 3. The frequency of electromagnetic oscillations is often in the microwave regime. This implies that the wavelength of field variations is comparable to the scale length of accelerator structures. The full set of the Maxwell equations must be used. Microwave theory relevant to accelerators is reviewed in this chapter. Chapter 13 describes the coupling of longitudinal particle dynamics to electromagnetic waves and introduces the concept of phase stability. The theoretical tools of this chapter and Chapter 13 will facilitate the study of specific resonant accelerators in Chapters 14 and 15. As an introduction to frequency-domain analysis, Section 12.1 reviews complex exponential representation of harmonic functions. The concept of complex impedance for the analysis of passive element circuits is emphasized. Section 12.2 concentrates on a lumped element model for 356 Resonant Cavities and Waveguides the fundamental mode of a resonant cavity. The Maxwell equations are solved directly in Section 12.3 to determine the characteristics of electromagnetic oscillations in resonant cavities.
    [Show full text]
  • Introduction to Waveguide Optics
    2572-4 Winter College on Optics: Fundamentals of Photonics - Theory, Devices and Applications 10 - 21 February 2014 Introduction to Waveguide Optics Jiri Ctroky Institute of Photonics and Electronics AS CR, v.v.i., Prague Czech Republic IntroductiontoWaveguideOptics JiƎítyroký [email protected] Instituteof Photonics and Electronics AS CR, v.v.i., Prague,CzechRepublic WINTER COLLEGE on OPTICS: Fundamentals of Photonics - Theory,Devices and Applications, 10 - 21 February 2014, Trieste - Miramare, Italy WhereIcomefrom… InstituteofPhotonics andElectronicsASCR,v.v.i. AcademyofSciencesoftheCzechRepublicisanonͲuniversityinstitutionforbasicandappliedresearchconsistingof54independentinstitutes WINTER COLLEGE on OPTICS: Fundamentals of Photonics - Theory,Devices and Applications, 10 - 21 February 2014, Trieste - Miramare, Italy 1 Examplesofwaveguidestructures opticalfibre channeloptical “ARROW” waveguide (antiresonantreflectingOW) longitudinally uniform microring angularly plasmonicwaveguide resonator uniform metal subwavelengthgrating photoniccrystal waveguide waveguide “gain/loss”waveguide loss gain longitudinally periodic etc… WINTER COLLEGE on OPTICS: Fundamentals of Photonics - Theory,Devices and Applications, 10 - 21 February 2014, Trieste - Miramare, Italy Theoreticalfundamentalsofopticalwaveguides Tentativelistoftopics • Planarwaveguides;waveguidemodes,theirproperties.Guidedandleakymodes. Othertypesofwaveguiding,guidingbyasingleinterface • Waveguidebends,whisperingͲgallerymodes,circularresonators • Channelwaveguides,approximateanalyticalmethods.
    [Show full text]