Silicon photonics for telecomminications and biomedicine

K10318

Engineering/Optics

Given silicon’s versatile material properties, use of low-cost silicon photonics continues to 

move beyond light-speed data transmission through fiber-optic cables and computer chips. Its 

application has also evolved from the device to the integrated-system level. A timely overview 

of this impressive growth, Silicon Photonics for Telecommunications and Biomedicine

summarizes state-of-the-art developments in a wide range of areas, including optical communi￾cations, wireless technologies, and biomedical applications of silicon photonics. 

With contributions from world experts, this reference guides readers through fundamental 

principles and focuses on crucial advances in making commercial use of silicon photonics a 

viable reality in the telecom and biomedical industries. Taking into account existing and antici￾pated industrial directions, the book balances coverage of theory and practical experimental 

research to explore solutions for obstacles to the viable commercialization of silicon photonics.

The book’s special features include

• A section on silicon plasmonic waveguides

• Detailed coverage of novel III-V applications

• A chapter on 3D integration

• Discussion of applications for energy harvesting/photovoltaics

This book reviews the most important technological trends and challenges. It presents topics 

involving major silicon photonics applications in telecommunications, high-power photonics, 

and biomedicine. It includes discussion of silicon plasmonic waveguides, piezoelectric tuning of 

silicon’s optical properties, and applications of two-photon absorption. Expert authors with 

industry research experience examine the challenge of hybridizing III-V compound semiconduc￾tors on silicon to achieve monolithic light sources. They also address economic compatibility and 

heat dissipation issues in CMOS chips, challenges in designing electronic photonics integrated 

circuits, and the need for standardization in computer-aided design of industrial chips. 

This book gives an authoritative summary of the latest research in this emerging field, covering 

key topics for readers from various disciplines with an interest in integrated photonics.

Silicon Photonics

for Telecommunications

and Biomedicine

ISBN: 978-1-4398-0637-1

9 781439 806371

9 0 0 0 0

Silicon

Photonics

for Telecommunications

and Biomedicine

Edited by

S a s a n Fat h p o ur

Ba h r a m J a l a l i

Silicon Photonics

for Telecommunications and Biomedicine

Fathpour

Jalali

Silicon

Photonics

for Telecommunications

and Biomedicine

CRC Press is an imprint of the

Taylor & Francis Group, an informa business

Boca Raton London New York

Silicon

Photonics

for Telecommunications

and Biomedicine

Edited by

Sasan Fathpour

Bahram Jalali

CRC Press

Taylor & Francis Group

6000 Broken Sound Parkway NW, Suite 300

Boca Raton, FL 33487-2742

© 2012 by Taylor & Francis Group, LLC

CRC Press is an imprint of Taylor & Francis Group, an Informa business

No claim to original U.S. Government works

Version Date: 20111101

International Standard Book Number-13: 978-1-4398-0638-8 (eBook - PDF)

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To Our Wives: Haleh and Mojgan

vii

Contents

Preface ix

Editors xiii

Contributors xv

Chapter 1 Silicon Photonics—The Evolution of Integration 1

Graham T. Reed, William R. Headley,

Goran Z. Mashanovich, Frederic Y. Gardes,

David J. Thomson, and Milan M. Milosevic

Chapter 2 Silicon Plasmonic Waveguides 51

Richard Soref, Sang-Yeon Cho, Walter Buchwald,

Robert E. Peale, and Justin Cleary

Chapter 3 Stress and Piezoelectric Tuning of Silicon’s Optical

Properties 77

Kevin K. Tsia, Sasan Fathpour, and Bahram Jalali

Chapter 4 Pulse Shaping and Applications of Two-Photon

Absorption 107

Ozdal Boyraz

Chapter 5 Theory of Silicon Raman Amplifiers and Lasers 131

Michael Krause, Hagen Renner, and Ernst Brinkmeyer

Chapter 6 Silicon Photonics for Biosensing Applications 201

Jenifer L. Lawrie and Sharon M. Weiss

Chapter 7 Mid-Wavelength Infrared Silicon Photonics for High￾Power and Biomedical Applications 231

Varun Raghunathan, Sasan Fathpour, and Bahram Jalali

Chapter 8 Novel III-V on Silicon Growth Techniques 255

Diana L. Huffaker and Jun Tatebayashi

viii ■ Contents

Chapter 9 Hybrid III-V Lasers on Silicon 297

Jun Yang, Zetian Mi, and Pallab Bhattacharya

Chapter 10 Three-Dimensional Integration of CMOS and

Photonics 341

Prakash Koonath, Tejaswi Indukuri, and Bahram Jalali

Chapter 11 Nonlinear Photovoltaics and Energy Harvesting 363

Sasan Fathpour, Kevin K. Tsia, and Bahram Jalali

Chapter 12 Computer-Aided Design for CMOS Photonics 383

Attila Mekis, Daniel Kucharski, Gianlorenzo Masini, and

Thierry Pinguet

ix

Preface

Today, silicon photonics, the technology for building low-cost

and complex optics on a chip, is a thriving community, and a

blossoming business. The roots of this promising new technol￾ogy date back to the late 1980s and early 1990s to the work of

Soref, Peterman, and others. There were three early findings that

paved the path for much of the subsequent progress. First, it was

recognized that micrometer-size waveguides, compatible with

the CMOS technology of the time, could be realized despite the

large refractive index difference between silicon and silicon diox￾ide (SiO2). Previously, this large refractive index was thought to

result in multimode waveguides that are undesirable for building

useful interferometric devices such as directional couplers, Mach–

Zehnder modulators, and so on. Although today’s submicron

(nanophotonic) waveguides are routinely realized and desired for

their more efficient use of wafer real estate, the advance fabrica￾tion capability needed to fabricate such structures was not widely

available to photonic device researchers. Second, it was proposed

by Soref that by modulating the free-carrier density, which can

be done easily with a diode or a transistor, electro-optic switch￾ing can be achieved through the resulting electroabsorption and

electrorefraction effects. Third, it was shown that infrared pho￾todectors operating in the telecommunication band centered at

1550 nm can be monolithically integrated onto silicon chips using

strained layer GeSi (and eventually Ge) grown directly on silicon.

The potential for creating low-cost photonics using the silicon

CMOS chip manufacturing infrastructure was gradually recog￾nized by the photonics research and business community in the

late 1990s and early 2000s. Fueling this development was the

concurrent commercial emergence of silicon-on-insulator (SOI)

CMOS as the platform of choice for high-performance comple￾mentary metal-oxide semiconductor (CMOS) processing. SOI

also offers an ideal platform for creating planar optical circuits

by providing an optically confining layer below the waveguide

core. Also, the strong optical confinement offered by the large

refractive index contrast between silicon and SiO2 makes it pos￾sible to scale down the size of photonic circuits. Such lateral and

vertical dimensions are required for economic compatibility with

integrated circuits (IC) processing. In addition, a large nonlinear

x ■ Preface

optical index in silicon plus a high optical intensity arising from

the large index contrast between Si and SiO2 make it possible

to create nonlinear optical devices in chip-scale devices such as

those based on Raman and Kerr nonlinearities. Optical ampli￾fiers, optically pumped lasers, and wavelength converters—func￾tions that were traditionally considered to be beyond the reach of

silicon—were created.

The potential forsilicon photonics extends beyond low-cost data

communication products. The compatibility with CMOS not￾withstanding, silicon has excellent material properties on its own.

These include high thermal conductivity (about 10 times higher

than gallium arsenide [GaAs]), high optical damage threshold

(about 100 times higher than GaAs), and high third-order optical

nonlinearities (about 100 times higher than silica optical fiber).

Silicon is highly transparent in the wavelength range of 1.1 μm to

nearly 7 μm. Furthermore, the absence of two-photon absorption

at wavelengths larger than 2.25 μm renders silicon an excellent

nonlinear optical material in the mid-wave infrared spectrum,

where there are numerous important applications in remote sens￾ing and biomedical applications.

Presently, it is believed that the highest impact of silicon pho￾tonics may be in optical interconnection between digital electronic

chips. This technology addresses the communication bottleneck in

very-large-scale integrated (VLSI) electronics. However, the ben￾efits of integrated optics and electronics extend beyond the realm

of computers. For example, in next-generation ultrasound medical

imaging systems, the rate for signals generated by the array of trans￾ducers will exceed 100 GBps, once digitized, and will continue to

increase asradiologists demand betterimage resolution.The size and

power dissipation of conventional optical transceivers prevent them

from being used in the imaging probe. Silicon integrated circuits

with on-chip optical interfaces can potentially solve this problem.

Applications beyond telecommunications are being pursued for

silicon photonics. For example, silicon photonics may be able to

produce disposable mass-produced biosensors. One likely appli￾cation is the so-called lab-on-a-chip in which both reaction and

analysis are performed on a single device. Such sensors, along

with integrated intelligence and wireless communication cir￾cuitry, may form nodes of an intelligent sensor network or envi￾ronmental monitoring. High-power photonic and biomedical

applications of silicon at mid-wave infrared are other possibilities

on the horizon.

Preface ■ xi

This book is meant to complement, rather than replace, previ￾ous books on silicon photonics. Indeed, there are the excellent

books edited by L. Pavesi and D. J. Lockwood (Silicon Photonics,

2004); G. T. Reed and A. P. Knights (Silicon Photonics: An

Introduction, 2004); G. T. Reed (Silicon Photonics: The State of the

Art, 2008); and L. Khriachtchev (Silicon Nanophotonics, 2009).

The topics covered in the present book are advanced, as famil￾iarity with integrated photonics, in general, and with basics of

silicon photonics, in particular, is assumed. Readers interested

in more fundamental topics may refer to the three books men￾tioned above.

We attempt to offer a balance between theory and experiment

on one hand, and current and forthcoming industrial trends on

the other. An introductory chapter reviews the present state of the

art and future trends and technological challenges. Following are

selected topics on two major applications of silicon photonics—

namely, telecommunications (Chapters 2 to 5) and high-power

photonics and biomedicine (Chapters 6 and 7). The next four

chapters are devoted to technological challenges that must still

be overcome if silicon photonics is to fulfill its destiny. Chapters

8 and 9 cover the challenge of hybridization of III-V compound

semiconductors on silicon in order to achieve monolithic light

sources. Economic compatibility and the heat dissipation prob￾lems in CMOS chips—important challenges that are often

neglected by the research community but reign supreme—are dis￾cussed in Chapters 9 and 10, respectively. The issues in the design

of electronic-photonics ICs and the need for standardization in

computer-aided design of industrial chips are addressed in the

final chapter of this book.

Last but not least, we would like to thank the authors of each

chapter for making this book possible.

xiii

Editors

Sasan Fathpour is an assistant pro￾fessor at the College of Optics and

Photonics (CREOL) at the University

of Central Florida (UCF). He also

holds a joint appointment at UCF’s

Department of Electrical Engineering

and Computer Science. He received a

PhD in electrical engineering from the

University of Michigan–Ann Arbor in

2005. He then joined the University

of California–Los Angeles (UCLA)

as a postdoctoral fellow. He won the

2007 UCLA Chancellor’s Award for

postdoctoral research for his work on

energy harvesting in silicon photon￾ics. Dr. Fathpour is a coauthor of over

70 journal and conference papers and

book chapters.

Bahram Jalali is a professor of elec￾trical engineering at UCLA, a fellow

of IEEE and of the Optical Society

of America, and recipient of the R.W.

Wood Prize from the Optical Society

of America. In 2005, he was elected

to the Scientific American Top 50, and

received the BrideGate 20 Award

in 2001 for his contributions to the

Southern California economy. Dr.

Jalali serves on the board of trustees of

the California Science Center and the

board of Columbia University School

of Engineering and Applied Sciences.

He has published over 300 journal and

conference papers and holds 8 patents.