Photodetector Characteristics in Visible Light Communication

Total Page:16

File Type:pdf, Size:1020Kb

Photodetector Characteristics in Visible Light Communication Photodetector Characteristics in Visible Light Communication Dissertation by Kang-Ting Ho In Partial Fulfillment of the Requirements For the Degree of Master of Science King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia © April, 2016 Kang-Ting Ho All Rights Reserved 2 EXAMINATION COMMITTEE APPROVALS FORM The dissertation of Kang-Ting Ho is approved by the examination committee: Committee Chairperson: Dr. Jr-Hau He Committee Member: Dr. Boon S. Ooi Committee Member: Dr. Lance Li Committee Member: Dr. Daniel Lau 3 ABSTRACT Photodetector Characteristics in Visible Light Communication Kang-Ting Ho Typically, in the semiconductor industry pn heterojunctions have been used as either light-emitting diodes (LED) or photodiodes by applying forward current bias or reverse voltage bias, respectively. However, since both devices use the same structure, the light emitting and detecting properties could be combine in one single device, namely LED-based photodetector. Therefore, by integrating LED-based photodetectors as either transmitter or receiver, optical wireless communication could be easily implemented for bidirectional visible light communication networks at low-cost. Therefore, this dissertation focus on the investigation of the photodetection characteristics of InGaN LED-based photodetectors for visible light communication in the blue region. In this regard, we obtain external quantum efficiency of 10 % and photoresponse rise time of 71 µs at 405-nm illumination, revealing high-performance photodetection characteristics. Furthermore, we use orthogonal frequency division multiplexing quadrature amplitude modulation codification scheme to enlarge the operational bandwidth. Consequently, the transmission rate of the communication is efficiently enhanced up to 420 Mbit/s in visible light communication. 4 ACKNOWLEDGEMENTS Earnestly thank King Abdullah Bin Abdulaziz Al Saud, and KAUST’s proceeding and current management who realize his dream and vision. I will always cherish the tremendous experiences gained in the past one and a half years. I sincerely thank my supervisor, Prof. Jr-Hau He, a dedicated scientist and entrepreneur with great passion and insights. His leadership and his constant support helped me accomplish this thesis dissertation. I would also like to express my appreciation to our laboratory manager, Dr. Jose Ramon Duran Retamal, who always help me push me to achieve high-performance as a top-quality engineer and scientific worker. Also thanks for all the valuable discussions and creative solutions. Special thanks to our senior lab member Dr. Cheng-Fang Kang who introduced me to this exciting field. Thanks to Prof. Boon S. Ooi for his suggestions and discussions during my research. He also kindly provided me with a high-technical environment to perform the experiments. Thanks also to Dr. Thien Khee Ng and Chao Shen for all the support provided during the experiments. Thanks to Prof. Hao-Chung Kuo form National Chiao Tung University for providing me with the devices, and to Dr. Yu-Lin Tsai for giving me a lot of suggestion about conceptualizing the project. Thanks to Prof. Gong-Ru Lin from National Taiwan University for elaborating the project design. Additional thanks to Dr. Yu-Chieh Chi, Cheng-Ting Tsai, and Huai-Yung Wang for their explanations and lectures about OFDM measurements. 5 TABLE OF CONTENTS Page EXAMINATION COMMITTEE APPROVALS FORM ....................................................... 2 ABSTRACT ................................................................................................................... 3 ACKNOWLEDGEMENTS ............................................................................................. 4 TABLE OF CONTENTS.................................................................................................. 5 LIST OF ABBREVIATIONS ............................................................................................ 7 LIST OF ILLUSTRATIONS.............................................................................................. 8 LIST OF TABLES ........................................................................................................... 9 1. Chapter One: Background ...................................................................................... 10 1.1 Introduction........................................................................................... 10 1.2 Motivation ............................................................................................. 10 1.3 Multiple quantum wells InGaN/GaN LED .............................................. 12 1.4 LED-based photodetector ..................................................................... 13 1.4.1 Responsivity & external quantum efficiency .......................... 14 1.4.2 Response time ........................................................................ 15 1.4.3 Frequency spectrum............................................................... 16 1.5 Orthogonal Frequency Division Multiplexing ....................................... 17 2. Chapter Two: Measurement Setup........................................................................ 19 2.1 Current–voltage characterization ......................................................... 19 2.2 Light source and responsivity calculation ............................................. 19 2.3 Light source and RC time constant measurement ................................ 20 2.4 Frequency spectrum measurement ...................................................... 21 2.5 Orthogonal Frequency Division Multiplexing ....................................... 22 3. Chapter Three: Devices Characterization .............................................................. 23 3.1 External Quantum Efficiency ................................................................. 23 3.2 Response Time ...................................................................................... 24 3.3 Frequency Spectrum ............................................................................. 25 3.4 Orthogonal Frequency Division Multiplexing ....................................... 26 3.4.1 Bias Voltage Depend .............................................................. 26 3.4.2 Start Frequency ...................................................................... 27 6 3.4.3 Bandwidth .............................................................................. 28 3.4.4 Summary ................................................................................ 30 4. Chapter Four: Conclusion....................................................................................... 31 BIBLIOGRAPHY……………………………………………………………………………………………………….. 32 7 LIST OF ABBREVIATIONS VLC Visible light communication OWC Optical wireless communication RF Radio frequency Li-Fi Light Fidelity LED Light-emitting diode PD Photodetector SSL Solid-state lighting OOK On-off keying YAG Y3Al5O12:Ce MQWs Multiple quantum wells OOK On-off keying FWHM Full width at half maximum OFDM Orthogonal frequency-division multiplexing FDM Frequency division multiplexing BER Bit error rate SNR Signal-to-noise ratio 4-QAM Quadrature phase shift keying FEC Forward error correction 8 LIST OF ILLUSTRATIONS Figure 1. White light spectrum of a coating YAG phosphor illuminated by blue light LED……………………………………………………............................................................................ 11 Figure 2. The band diagram of AlGaN/GaN/InGaN MQWs structure.............................. 13 Figure 3. Output wave forms of the LED-based PD.......................................................... 14 Figure 4. (a) The current-voltage characteristics of perovskite solution-processed hybrid perovskite PDs…………...................................................................................................... 15 Figure 5. The relation between the optical signal and electrical response of PD…......... 16 Figure 6. The spectrum efficiency is improved by OFDM modulation............................. 18 Figure 7. The different bit-to-symbol mapping for OFDM…............................................ 18 Figure 8. The profile shows the size of light spot and power intensity distribution which is uniform that we can calculate the power illuminated on devices............................... 19 Figure 9. The profile shows the size of laser spot and power intensity distribution which is Gaussian beam that we can calculate the power illuminated on devices…................. 21 Figure 10. The LED is used gold wire bonding bonded on a designed mount…............... 22 Figure 11. The structure of InGaN/GaN MQW LED…....................................................... 23 Figure 12. The photonics-electronics performance of LED-based PD.............................. 23 Figure 13. The time response measurement illuminated 405 nm laser diode which maximum power is 900 mW……………………………………………............................................. 24 Figure 14. The temporal characteristics of LED-based PD............................................... 25 Figure 15. The frequency spectrum of LED-based PD is applied in different bias........... 26 Figure 16. The OFDM testing depends on different bias voltage……………………............... 26 Figure 17. The BER and SNR plot shows start frequency only 2.34 GHz pass the FEC limit………………………………………………………………………………………………………………............... 28 Figure 18. The start frequency of bandwidth testing is 2.34 GHz…………………................. 29 9 LIST OF TABLES Table 1. The BER and SNR value is measured in
Recommended publications
  • DESIGN and EVALUATION of CONTROLS for DRIFT, VIDEO GAIN, and COLOR BALANCE in SPACEBORNE FACSIMILE CAMERAS by Stephen J. Katrber
    NASA TECHNICAL NOTE @ NASA Tli D-73.3 m % & m U.S.A. m (NASA-TN-D-7333) DESIGN AND EVALUATION OP CONTROLS FOR DRIFT, VIDEO GAIN, AND COLOR BALANCE IN SPACEBORNE FACSIMILE CAMERAS (NASA) 33 p HC $3.00 CSCL 14E Unclas 4 81/10 23462 Z DESIGN AND EVALUATION OF CONTROLS FOR DRIFT, VIDEO GAIN, AND COLOR BALANCE IN SPACEBORNE FACSIMILE CAMERAS by Stephen J. Katrberg, W. Lane Kelly IV, QR~Q~F~&$.MH?AlMS Carroll W. Rowland, and Ernest E. Burcher GQdhU.* . .b"'3H8 Langley Research Center Humpton, Vu. 23665 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. DECEMBER 1973 1. Report No. a. Government Accasrion No. 3. Recipient's Catalog No. NASA TN D-7333 4. Title and Subtitle 5. Report Date DESIGN AND EVALUATION OF CONTROLS FOR DRIFT, December 1973 VIDEO GAIN, AND COLOR BALANCE IN SPACEBORNE 6. Performing Organization Code FACSIMILE CAMERAS 7. Author(s1 8. Performing Organization Rwrt No. Stephen J. Katzberg, W. Lane Kelly IV, Carroll W. Rowland, L-8845 and Ernest E. Burcher 10. Work Unit No. g. Rrforming Organintion Name and Addrerr 502-03-52-04 NASA Langley Research Center 11. Contract or Grant No. Hampton, Va. 23665 13. Type of Repon and Period Covered 12. Sponsoring Agency Name and Addresr Technical Note National Aeronautics and Space Administration 14. Sponsoring Agency Code Washington, D.C. 20546 15:' Subplementary Notes 16. AbsuaR The facsimile camera is an optical-mechanical scanning device which has become an attractive candidate as an imaging system for planetary landers and rovers. This paper presents electronic techniques which permit the acquisition and reconstruction of high-quality images with this device, even under varying lighting conditions.
    [Show full text]
  • Leds As Single-Photon Avalanche Photodiodes by Jonathan Newport, American University
    LEDs as Single-Photon Avalanche Photodiodes by Jonathan Newport, American University Lab Objectives: Use a photon detector to illustrate properties of random counting experiments. Use limiting probability distributions to perform statistical analysis on a physical system. Plot histograms. Condition a detector’s signal for further electronic processing. Use a breadboard, power supply and oscilloscope to construct a circuit and make measurements. Learn about semiconductor device physics. Reading: Taylor 3.2 – The Square-Root Rule for a Counting Experiment pp. 48-49 Taylor 5.1-5.3 – Histograms and the Normal Distribution pp. 121-135 Taylor Ch. 11 – The Poisson Distribution pp. 245-254 Taylor Problem 5.6 – The Exponential Distribution p. 155 Experiment #1: Lighting an LED A Light-Emitting Diode is a non-linear circuit element that can produce a controlled amount of light. The AND113R datasheet shows that the luminous intensity is proportional to the current flowing through the LED. As illustrated in the IV curve shown below, the current flowing through the diode is in turn proportional to the voltage across the diode. Diodes behave like a one-way valve for current. When the voltage on the Anode is more positive than the voltage on the Cathode, then the diode is said to be in Forward Bias. As the voltage across the diode increases, the current through the diode increases dramatically. The heat generated by this current can easily destroy the device. It is therefore wise to install a current-limiting resistor in series with the diode to prevent thermal runaway. When the voltage on the Cathode is more positive than the voltage on the Anode, the diode is said to be in Reverse Bias.
    [Show full text]
  • Floating-Gate Transistor Photodetector
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Mechanical & Materials Engineering Faculty Mechanical & Materials Engineering, Publications Department of 10-10-2017 Floating-Gate Transistor Photodetector Jinsong Huang University of Nebraska-Lincoln, [email protected] Yongbo Yuan Lincoln, NE Follow this and additional works at: https://digitalcommons.unl.edu/mechengfacpub Part of the Mechanics of Materials Commons, Nanoscience and Nanotechnology Commons, Other Engineering Science and Materials Commons, and the Other Mechanical Engineering Commons Huang, Jinsong and Yuan, Yongbo, "Floating-Gate Transistor Photodetector" (2017). Mechanical & Materials Engineering Faculty Publications. 393. https://digitalcommons.unl.edu/mechengfacpub/393 This Article is brought to you for free and open access by the Mechanical & Materials Engineering, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Mechanical & Materials Engineering Faculty Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. THULHUILUWUTTURUS009786857B2 (12 ) United States Patent ( 10 ) Patent No. : US 9 ,786 , 857 B2 Huang et al. ( 45 ) Date of Patent : Oct . 10 , 2017 ( 54 ) FLOATING -GATE TRANSISTOR ( 58 ) Field of Classification Search PHOTODETECTOR CPC .. .. .. HO1L 31/ 1136 ; HO1L 51/ 0052 ; HOLL 51/ 428 ; YO2E 10 / 549 (71 ) Applicant : NUtech Ventures, Lincoln , NE (US ) See application file for complete search history . ( 72 ) Inventors : Jinsong Huang , Lincoln , NE (US ) ; ( 56 ) References Cited Yongbo Yuan , Lincoln , NE (US ) U . S . PATENT DOCUMENTS ( 73 ) Assignee : NUtech Ventures, Lincoln , NE (US ) 2007/ 0063304 A1 * 3 / 2007 Matsumoto .. B82Y 10 / 00 257 /462 ( * ) Notice : Subject to any disclaimer, the term of this 2010 /0155707 A1* 6 /2010 Anthopoulos .. B82Y 10 /00 patent is extended or adjusted under 35 257 /40 U .
    [Show full text]
  • Mos2 Based Photodetectors: a Review
    sensors Review MoS2 Based Photodetectors: A Review Alberto Taffelli *, Sandra Dirè , Alberto Quaranta and Lucio Pancheri Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123 Trento, Italy; [email protected] (S.D.); [email protected] (A.Q.); [email protected] (L.P.) * Correspondence: [email protected] Abstract: Photodetectors based on transition metal dichalcogenides (TMDs) have been widely reported in the literature and molybdenum disulfide (MoS2) has been the most extensively explored for photodetection applications. The properties of MoS2, such as direct band gap transition in low dimensional structures, strong light–matter interaction and good carrier mobility, combined with the possibility of fabricating thin MoS2 films, have attracted interest for this material in the field of optoelectronics. In this work, MoS2-based photodetectors are reviewed in terms of their main performance metrics, namely responsivity, detectivity, response time and dark current. Although neat MoS2-based detectors already show remarkable characteristics in the visible spectral range, MoS2 can be advantageously coupled with other materials to further improve the detector performance Nanoparticles (NPs) and quantum dots (QDs) have been exploited in combination with MoS2 to boost the response of the devices in the near ultraviolet (NUV) and infrared (IR) spectral range. Moreover, heterostructures with different materials (e.g., other TMDs, Graphene) can speed up the response of the photodetectors through the creation of built-in electric fields and the faster transport of charge carriers. Finally, in order to enhance the stability of the devices, perovskites have been exploited both as passivation layers and as electron reservoirs. Keywords: MoS2; TMD; photodetector; heterostructure; thin film Citation: Taffelli, A.; Dirè, S.; Quaranta, A.; Pancheri, L.
    [Show full text]
  • Organic Light-Emitting and Photodetector Devices for Flexible
    REVIEW PAPER IEICE Electronics Express, Vol.14, No.20, 1–16 Organic light-emitting and photodetector devices for flexible optical link and sensor devices: Fundamentals and future prospects in printed optoelectronic devices for high-speed modulation Hirotake Kajiia) Graduate School of Engineering, Osaka University, 2–1 Yamada-oka, Suita, Osaka 565–0871, Japan a) [email protected] Abstract: This paper describes the application of organic photonic devices including organic light-emitting and photodetector devices to integrated photonic devices for the realization of flexible optical link and sensor devices. Fundamentals and future prospects in printed optoelectronic devices for high-speed modulation are discussed and reviewed. Keywords: organic light-emitting diodes, organic photodetectors, organic light-emitting transistor, high speed, printed electrodes, sensor Classification: Electron devices, circuits and modules References [1] M. A. Baldo, et al.: “Very high-efficiency green organic light emitting devices based on electro-phosphorescence,” Appl. Phys. Lett. 75 (1999) 4 (DOI: 10. 1063/1.124258). [2] H. Uoyama, et al.: “Highly efficient organic light-emitting diodes from delayed fluorescence,” Nature 492 (2012) 234 (DOI: 10.1038/nature11687). [3] Y. Ohmori, et al.: “Realization of polymeric optical integrated devices utilizing organic light emitting diodes and photo detectors fabricated on a polymeric waveguide,” IEEE J. Sel. Top. Quantum Electron. 10 (2004) 70 (DOI: 10.1109/ JSTQE.2004.824106). [4] H. Kajii, et al.: “Organic light-emitting diode fabricated on a polymer substrate for optical links,” Thin Solid Films 438–439 (2003) 334 (DOI: 10.1016/S0040- 6090(03)00753-3). [5] H. Kajii, et al.: “Transient properties of organic electroluminescent diode using 8-Hydroxyquinoline aluminum doped with rubrene as an electro-optical conversion device for polymeric integrated devices,” Jpn.
    [Show full text]
  • Photovoltaic Couplers for MOSFET Drive for Relays
    Photocoupler Application Notes Basic Electrical Characteristics and Application Circuit Design of Photovoltaic Couplers for MOSFET Drive for Relays Outline: Photovoltaic-output photocouplers(photovoltaic couplers), which incorporate a photodiode array as an output device, are commonly used in combination with a discrete MOSFET(s) to form a semiconductor relay. This application note discusses the electrical characteristics and application circuits of photovoltaic-output photocouplers. ©2019 1 Rev. 1.0 2019-04-25 Toshiba Electronic Devices & Storage Corporation Photocoupler Application Notes Table of Contents 1. What is a photovoltaic-output photocoupler? ............................................................ 3 1.1 Structure of a photovoltaic-output photocoupler .................................................... 3 1.2 Principle of operation of a photovoltaic-output photocoupler .................................... 3 1.3 Basic usage of photovoltaic-output photocouplers .................................................. 4 1.4 Advantages of PV+MOSFET combinations ............................................................. 5 1.5 Types of photovoltaic-output photocouplers .......................................................... 7 2. Major electrical characteristics and behavior of photovoltaic-output photocouplers ........ 8 2.1 VOC-IF characteristics .......................................................................................... 9 2.2 VOC-Ta characteristic ........................................................................................
    [Show full text]
  • Arxiv:1606.02774V1 [Physics.Ins-Det] 8 Jun 2016
    Inexpensive LED-based spectrophotometer for analyzing optical coatings Kayla Hardie,∗ Sascha Agne, Katanya B. Kuntz, and Thomas Jennewein Department of Physics and Astronomy and Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada (Dated: June 10, 2016) Abstract Optical coatings are widespread in everyday life, from camera lenses to glasses, to complex optics experiments. A simple, reliable device that can quickly and inexpensively analyze optical coatings is a valuable laboratory tool. Such a device can identify unknown or mislabelled optics, and characterize the transmission spectra of optical elements used in an experiment. We present the design and characterization of a LED-based spectrophotometer, and demonstrate its ability to identify different optical coatings. Our approach uses ten LEDs that cover a spectrum from 365 nm to 1000 nm. A small servomotor and microcontroller rotates a LED board to sequentially position each LED over an optical sample, and the transmitted light corresponding to each LED is measured with a silicon photodetector. The device is automated, portable, inexpensive, user-friendly and simple to build. arXiv:1606.02774v1 [physics.ins-det] 8 Jun 2016 1 I. INTRODUCTION An optical coating is composed of one or several thin film layers, each with carefully chosen thicknesses and indexes of refraction. The coatings are deposited onto the surface of an optical element, such as a lens or wave plate, to alter the reflection and transmission for particular wavelengths. Coatings are widespread in everyday life, from camera lenses to banknote security, and are equally important in optics manufacturing and research. For instance, anti-reflective coatings are used to minimize the four percent transmission loss at air-glass interfaces.1 In a laboratory setting, the ability to analyze the performance of an optical coating for a given spectrum is extremely useful.
    [Show full text]
  • Amplified Photodetector User's Guide
    AMPLIFIED PHOTODETECTOR USER’S GUIDE Thank you for purchasing your Amplified Photodetector. This user’s guide will help answer any questions you may have regarding the safe use and optimal operation of your Amplified Photodetector. TABLE OF CONTENTS I. Amplified Photodetector Overview ................................................................................................................. 1 II. Operation of your Amplified Photodetector .................................................................................................... 1 III. Troubleshooting ............................................................................................................................................... 2 IV. Drawings: Amplified Photodetectors .............................................................................................................. 2 V. Specifications: Amplified Photodetectors ....................................................................................................... 3 VI. Schematics: Amplified Photodetectors ............................................................................................................ 3 VII. Glossary of Terms .......................................................................................................................................... 4 I. Amplified Photodetector Overview The Amplified Photodetectors contain PIN photodiodes that utilize the photovoltaic effect to convert optical power into an electrical current. Figure 1 below identifies the main elements of
    [Show full text]
  • Ultraviolet Degradation Study of Photomultiplier Tubes at SURF III
    Ultraviolet degradation study of photomultiplier tubes at SURF III Lindsay Hum*a, Ping-Shine Shawb, Zhigang Lib, Keith R. Lykkeb and Michael L. Bishopa aNaval Surface Warfare Center, Corona, CA USA 92878 bNational Institute of Standards and Technology, Gaithersburg, MD USA 20899 ABSTRACT Photomultiplier tubes (PMTs) are used in biological detection systems in order to detect the presence of biological warfare agents. To ensure proper operation of these biological detection systems, the performance of PMTs must be characterized in terms of their responsivity and long-term stability. We report a technique for PMT calibration at the Synchrotron Ultraviolet Radiation Facility (SURF III) at the National Institute of Standards and Technology (NIST). SURF III provides synchrotron radiation with a smooth and continuous spectrum covering the entire UV range for accurate PMT measurements. By taking advantage of the ten decade variability in the flux of the synchrotron radiation, we studied properties of commercial PMTs such as the linearity, spatial uniformity, and spectral responsivity. We demonstrate the degradation of PMTs by comparing new PMTs with PMTs that were used and operated in a biological detection system for a long period of time. The observed degradation is discussed. Keywords: photomultiplier tubes, ultraviolet, degradation, synchrotron radiation, calibration 1. INTRODUCTION The threat of biological attacks on the United States homeland and military forces overseas continues to expand. As a result, the Department of Defense (DoD) has a growing need for accurate and reliable biological detection systems [1] to counter the threat and ensure the safety and mission effectiveness of the warfighters. Biological point detection systems provide commanders with information in order to take protective actions and limit biological warfare agent exposure to the warfighters.
    [Show full text]
  • Ultra-Sensitive Sige Bipolar Phototransistors for Optical Interconnects
    Ultra-sensitive SiGe Bipolar Phototransistors for Optical Interconnects Michael Roe Electrical Engineering and Computer Sciences University of California at Berkeley Technical Report No. UCB/EECS-2012-123 http://www.eecs.berkeley.edu/Pubs/TechRpts/2012/EECS-2012-123.html May 27, 2012 Copyright © 2012, by the author(s). All rights reserved. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. Ultra-Sensitive SiGe Bipolar Phototransistors for Optical Interconnects by Michael Roe Research Project Submitted to the Department of Electrical Engineering and Computer Sciences, University of California at Berkeley, in partial satisfaction of the requirements for the degree of Master of Science, Plan II. Approval for the Report and Comprehensive Examination: Committee: Professor Eli Yablonovitch Research Advisor 5/10/2012 (Date) * * * * * * * Professor Ming Wu Second Reader 5/9/2012 (Date) Table of Contents 1. Introduction ..................................................................................................................................1 1 2. Homojunction Bipolar Phototransistors ....................................................................................3 2 2.1 Photo-BJT Gain Model ....................................................................................................3
    [Show full text]
  • Transistor-Based Ge/SOI Photodetector for Integrated Silicon Photonics
    Transistor-Based Ge/SOI Photodetector for Integrated Silicon Photonics By Xi Luo A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy In Engineering-Electrical Engineering and Computer Sciences in the GRADUATE DIVISION of the UNIVERSITY OF CALIFORNIA, BERKELEY Committee in charge: Professor Eli Yablonovitch, Chair Professor Ming C. Wu Professor Irfan Siddiqi Spring 2011 Abstract Transistor-Based Ge/SOI Photodetector for Integrated Silicon Photonics by Xi Luo Doctor of Philosophy in Engineering – Electrical Engineering and Computer Sciences University of California, Berkeley Professor Eli Yablonovitch, Chair This dissertation describes our effort on developing a technology of photodetectors for application in chip-level optical communication. The photodetector proposed in this thesis work is the Ge/SOI Photo-Hetero-JFET. It is based on a silicon junction-FET in which the traditional electrical gate is replaced by a photo-active germanium mesa. The silicon channel conductance is then modulated by near-infrared light signal incident on the germanium gate. The limitations of traditional electrical wires which restrict the performance of microelectronic information systems drive researchers to look at optical interconnects as a good alternative for inter-chip data communication. One of the major challenges that the optics solution faces is to achieve as low energy consumption as 100aJ/bit. This in turn sets stringent requirements on the sensitivity of photodetectors, which can only be achieved when the photodetector can be highly integrated and has extremely small device capacitance (<1fF). The Ge/SOI Photo-Hetero-JFET is seamlessly integratable with microelectronic circuitry and also scalable to achieve extremely small capacitance.
    [Show full text]
  • 1. Photodetectors for Silicon Photonic Integrated Circuits
    Photodetectors for silicon photonic integrated circuits 1 Molly Piels and John E. Bowers Department of Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, CA, USA 1.1 Introduction Silicon-based photonic components are especially attractive for realizing low-cost pho- tonic integrated circuits (PICs) using high-volume manufacturing processes (Heck et al., 2013). Due to its transparency in the telecommunications wavelength bands near 1310 and 1550 nm, silicon is an excellent material for realizing low-loss passive opti- cal components. For the same reason, it is not a strong candidate for sources and detec- tors, and photodetector fabrication requires the integration of either III/V materials or germanium if high speed and high efficiency are required. Photodetectors used in pho- nic integrated circuits, like photodetectors used in most other applications, typically require large bandwidth, high efficiency, and low dark current. In addition, the devices must be waveguide-integrated (rather than surface-illuminated) and the process used to fabricate the photodiode must be compatible with the processes used to fabricate other components on the chip. For many applications where PICs are a promising solution, for example microwave frequency generation, coherent receivers, and optical intercon- nects relying on receiverless circuit designs (Assefa et al., 2010b), the maximum out- put power is also an important figure of merit. There are numerous design trade-offs between speed, efficiency, and output power. Designing for high bandwidth favors small devices for low capacitance. Small devices require abrupt absorption profiles for good efficiency, but design for high output power favors large devices with dilute absorption.
    [Show full text]