Silicon Photonics: Fueling the Next Information Revolution

By Daryl Inniss and Roy Rubenstein

Silicon photonics uses chip-making techniques to fabricate photonic circuits. The emerging technology is coming to market at a time of momentous change. The need of the Internet content providers to keep scaling their data centers is becoming increasing challenging, the chip industry is facing a future without Moore’s law, while telcos must contend with a looming capacity crunch due to continual traffic growth.

Each of these developments is significant in its own right. Collectively, they require new thinking in the design of chips, optical components, and systems. Such change also signals new business opportunities and disruption.

Notwithstanding challenges, silicon photonics’ emergence is timely because it is the future of several industries. For the optical industry, the technology will allow designs to be tackled in new ways. For the chip industry, silicon photonics will become the way of scaling post-Moore’s law. New system architectures enabled by silicon photonics will improve large-scale computing and optical communications.

Silicon Photonics: Fueling the Next Information Revolution outlines the history and status of silicon photonics. The book discusses the trends driving the datacom and telecom industries, the main but not the only markets for silicon photonics. In particular, developments in optical transport and the data center are discussed as are the challenges. The book details the many roles silicon photonics will play, from wide area networks down to the chip level. Silicon photonics is set to change the optical components and chip industries; this book explains how.

• Captures the latest research assessing silicon photonics development and prospects
• Demonstrates how silicon photonics addresses the challenges of managing bandwidth over distance and within systems
• Explores potential applications of SiP, including servers, datacenters, and Internet of Things

• Language: English
• Publisher: Elsevier Science
• Release date: Dec 5, 2016
• ISBN: 9780128029923

Daryl Inniss

Daryl Inniss is Director, New Business Development at OFS. He was formerly Components Practice Leader at market research firm Ovum and RHK. Daryl has been in the telecom industry for over 25 years. He was Technical Manager at JDSU and Lucent Technologies, Bell Laboratories. Daryl started his career as a Member of the Technical Staff, AT&T Bell Labs. Daryl holds a PhD in Chemistry from UCLA and an AB from Princeton University.

Book preview

Silicon Photonics

Fueling the Next Information Revolution

Daryl Inniss

Roy Rubenstein

Table of Contents

Cover image

Title page

Copyright

Dedication

Preface

The Reasoning for the Book and Its Organization

References

Acknowledgments

Chapter 1. Silicon Photonics: Disruptive and Ready for Prime Time

Abstract

1.1 Introduction

1.2 Silicon Photonics: An Introduction

1.3 The Significance of Silicon Photonics

1.4 The Status of Silicon Photonics

1.5 Silicon Photonics: Market Opportunities and Industry Disruption

References

Chapter 2. Layers and the Evolution of Communications Networks

Abstract

2.1 Introduction

2.2 The Concept of Layering

2.3 The Telecom Network—Layer 4

2.4 The Data Center—Layer 3

2.5 Platforms—Layer 2

2.6 The Silicon Chip—Layer 1

2.7 Telecom and Datacom Industry Challenges

2.8 Silicon Photonics: Why the Technology Is Important for All the Layers

References

Chapter 3. The Long March to a Silicon-Photonics Union

Abstract

3.1 Moore’s Law and 50 Years of the Chip Industry

3.2 How Photonics Can Benefit Semiconductors

3.3 Silicon Photonics: From Building Blocks to Superchips

3.4 The Building Blocks of Silicon Photonics Integrated Circuits

References

Chapter 4. The Route to Market for Silicon Photonics

Abstract

4.1 The Technology Adoption Curve

4.2 A Brief History of Silicon Photonics

4.3 Four Commercial Silicon Photonics Product Case Studies

4.4 What Silicon Photonics Needs to Go Mainstream

4.5 100-Gb Market Revenues Are Insufficient for Silicon Photonics

4.6 The Silicon Photonics Ecosystem: A State-of-the-Industry Report

References

Chapter 5. Metro and Long-Haul Network Growth Demands Exponential Progress

Abstract

5.1 The Changing Nature of Telecom

5.2 Internet Businesses Have the Fastest Network Traffic Growth

5.3 The Market Should Expect Cost-per-Transmitted-Bit to Rise

5.4 Data Center Interconnect Equipment

5.5 The Role of Silicon Photonics for Data Center Interconnect

5.6 Tackling Continual Traffic Growth

5.7 Pulling It All Together

References

Chapter 6. The Data Center: A Central Cog in the Digital Economy

Abstract

6.1 Internet Content Providers Are Driving the New Economy

6.2 Cloud Computing: Another Growth Market

6.3 The Expansive Build-Out of Data Centers

6.4 Energy Consumption Poses the Greatest Data Center Challenge

6.5 Silicon Photonics Can Address Data Center Challenges

References

Chapter 7. Data Center Architectures and Opportunities for Silicon Photonics

Abstract

7.1 Introduction

7.2 Internet Content Providers Are the New Drivers of Photonics

7.3 Data Center Networking Architectures and Their Limitations

7.4 Embedding Optics to Benefit Systems

7.5 Data Center Input–Output Challenges

7.6 Adding Photonics to Ultralarge-Scale Chips

7.7 Pulling It All Together

References

Chapter 8. The Likely Course of Silicon Photonics

Abstract

8.1 Looking Back to See Ahead

8.2 The Market Opportunities for Silicon Photonics: The Present to 2026

8.3 The Great Cultural Divide

8.4 The Chip Industry Will Own Photonics

References

Appendix 1. Optical Communications Primer

A1.1 Optical Links

A1.2 Optical Component Technologies

A1.3 Attenuation Characteristics of Fiber

A1.4 Optical Modules

References

Appendix 2. Optical Transmission Techniques for Layer 4 Networks

A2.1 The Three Classes of Optical Channel

A2.2 Single-Carrier 100-Gb Transmission With Coherent Detection

A2.3 Improving Spectral Efficiency

A2.4 Higher-Order Modulation

A2.5 The Levers Used to Boost Transmission Capacity

References

Index

Copyright

Morgan Kaufmann is an imprint of Elsevier

50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States

Copyright © 2017 Daryl Inniss and Roy Rubenstein. Published by Elsevier Inc. All rights reserved.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions.

This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).

Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.

Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.

To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library

Library of Congress Cataloging-in-Publication Data

A catalog record for this book is available from the Library of Congress

ISBN: 978-0-12-802975-6

For Information on all Morgan Kaufmann publications visit our website at https://www.elsevier.com

Publisher: Todd Green

Acquisition Editor: Todd Green

Editorial Project Manager: Charlie Kent

Production Project Manager: Priya Kumaraguruparan

Cover Designer: Vicky Pearson Esser

Typeset by MPS Limited, Chennai, India

Dedication

This body of work is dedicated to my wife and our wonderful children.

Daryl Inniss

To my mother and my late father. He would have loved to discuss the issues raised in this book.

Roy Rubenstein

Preface

We started writing this book in late 2014. At the time, silicon photonics was in a quiet period. The excitement that greeted the early announcements and later a spate of silicon photonics acquisitions had, by then, been replaced by pragmatism as the industry understood not only the technology’s merits but also its challenges. Many in the industry were keeping a watching brief while others remained skeptical, questioning whether silicon photonics was a viable technology [1,2].

Silicon photonics’ quiet period has ended. As we complete the book in late 2016, the year has seen more players enter the marketplace with silicon photonics’ products, more acquisitions, and even a successful initial public offering, by Acacia Communications.

However, in one sense the larger picture has not changed: people have long recognized the potential of silicon, and there have also been voices of pragmatism. Take this view from Simon Sherrington, talking in 2009 about his Light Reading report on silicon photonics: Silicon Photonics is changing the way vendors do photonic integration and has the potential to disrupt the supply chain. [3] And a Nature Photonics paper did an important job to dispel some of the myths that were being associated with silicon photonics. The paper also stated this: The bottom line is that individual silicon devices will probably not outperform single devices based on other material platforms, except in a few particular areas. The applications that will benefit most from the silicon platform are those that require many devices to be strung together into a complex system, just like in electronics. [4] In late 2016 both statements remain true.

Silicon photonics is coming to market at a time of momentous change. One significant trend is the rise of the Internet content providers and the developments taking place in the data center. These developments are having a knock-on effect for the communications service providers—telcos—which are now undertaking their own transformation. A second change is the end of Moore’s law. The chip industry is currently grappling with a wave of company consolidations, while the end of Moore’s law will have far-reaching consequences. Meanwhile, the optical industry faces its own issues as the bandwidth-carrying capacity of fiber starts to be approached. Optical fiber has been seen as a communications medium of near-boundless capacity. The growth in Internet traffic, the use of smartphones, and subscribers’ appetite for video means that is no longer true.

Each of these developments—the data center, the end of Moore’s law, and the looming capacity crunch—is significant in its own right. But collectively they signify a need for new thinking for chips, optics, and systems, as well as new business opportunities and industry change. Silicon photonics is arriving at a propitious time.

Despite this, the optical industry still has questions regarding the significance of silicon photonics. Meanwhile, for the chip industry optics remains a science peripheral to their daily concerns. This too will change.

As implied by its name, silicon photonics is set to influence both industries. For the optical industry, the technology will allow designs to be tackled in new ways. For the chip industry, silicon photonics may be a peripheral if interesting technology, but it will impact chip design. Silicon photonics may have hurdles to overcome, but it is a technology that no one will be able to ignore.

We felt the timing was right for a book that synthesizes the significant changes taking place in the datacom, telecom, and semiconductor industries and explains the market opportunities that will result and the role silicon photonics can play.

We have cast a wide net across these industries for a reason: we see it as a vital exercise to understand the significance of silicon photonics. Indeed, the book shows that silicon photonics will be a key technology for a post-Moore’s law era, and we argue that it will be the chip industry, not the photonics industry, that will drive optics.

The Reasoning for the Book and Its Organization

Let us start by saying what this book is not. It is not a traditional textbook—there is almost no math. Nor is it a compendium of the latest research work of the leading academics in the field. It is also not a how-to design book. Wonderful examples of such books exist. Nor is it a detailed market research report.

Instead, we have set ourselves a wider brief to look across important industries to tell the story of a key technology that is coming to market. To tell this story, we have broadened the context not just for the optical community but for the chip industry. The book is deliberately written with the assumption that not all the readership is familiar with optics or with the chip industry. We have brought in the voices of key silicon photonics luminaries who have played an important role in bringing the technology to market to tell some of their stories. These individuals have thought deeply about the technology and its likely ramifications.

The book focuses on the telecom and datacom industries, which are and will remain the primary markets for silicon photonics for the next decade at least. But we also note other developments where silicon photonics can play an important role.

A work of this nature must include some technical topics in optical communications, networking, and systems architectures. We have aimed to write these at a level that details what is needed without taking the reader on a detour. Interested readers will find appendices which give a more detailed discussion.

The main audiences for this book include design engineers of components—chips and optical components— as well as systems designers for a range of devices, from optical modules to telecom and datacom equipment. It is also written for sales and marketing executives who want to understand the broader developments in their industry, the changes taking place, and the key technologies. We have also targeted the book at press relations and media executives working in these industries.

Lastly, one of the silicon photonics luminaries, Lionel Kimerling, professor of materials science and engineering at MIT, told us how he is spending most of his time working with AIM Photonics, a US public–private venture established to advance the manufacturing of silicon photonics. Professor Kimerling is putting together educational material to help attract individuals to pursue a career in silicon photonics. Much of the technology is in place, he says; what is required is to make it accessible to people. I don’t have 40 more years in the industry, but I could influence the next 40 years by creating these instructional materials and career paths, and getting roadmap consensus that can drive the industry, says Kimerling.

In a very modest way, we hope this book also plays a role in realizing Professor Kimerling’s vision and is read by students considering their engineering options.

The chart shown on the previous page summarizes the book’s content at a glance.

Please visit the book companion website http://booksite.elsevier.com/9780128029756/ for full color versions of the figures in this book.

References

1. Silicon photonics a viable technology? Datacenter J. <http://www.datacenterjournal.com/silicon-photonics-viable-technology/>; July 6, 2016.

2. Knocking of silicon photonics now mainstream. Fibereality, <http://fibereality.com/blog/knocking-of-silicon-photonics-now-mainstream/>; April 2015.

3. Silicon carves out its niche as an optical material. Fibre Systems Europe; March–April 2009, pp. 18–21.

4. Baehr-Jones T, et al. Myths and rumours of silicon photonics. Nat Photonics. April 2012;6:206–208.

Acknowledgments

Daryl Inniss and Roy Rubenstein

We are indebted to the many people who have contributed to the creation of this book.

First of all, we would like to express deep thanks to Lance Leventhal without whom this work would not exist.

We would also like to express our gratitude to the silicon photonics luminaries who agreed to be interviewed: Andrew Rickman, Mario Paniccia, Graham Reed, Richard Soref, Chris Doerr, Philippe Absil, Joris Van Campenhout, John Bowers, Mehdi Asghari, Keren Bergman, Lionel Kimerling, Sanjay Patel, Young-Kai Chen, and Peter De Dobbelaere. We would also like to thank the many telecom and datacom experts we interviewed, all of whom contributed generously with their knowledge and their time.

We are grateful to the industry analysts who allowed us to cite their work and shared their insights, in particular Vladimir Kozlov, Dale Murray, and John Lively at LightCounting and Julie Kunstler, Ian Redpath, and Matt Walker at Ovum and Ron Kline and Mark Newman who were formerly at Ovum. We would also like to point out our involvement with these two market research companies. Inniss was until early 2016 vice president and practice leader of Ovum’s components practice, while Rubenstein is a consultant at LightCounting.

We would like to express our gratitude to Jean Atelsek for her tireless work and invaluable comments while editing the book. Thanks also to Martin Rubenstein for his careful readings and suggestions improved the book. In turn, we would like to thank the following for their comments and feedback while the book was being written: Brandon Collings, Joris Van Campenhout, Gareth Spence, Victoria McDonald, Martin Hull, Eric Hall, Glenn Wellbrock, Julie Kunstler, Karen Liu, Vladimir Kozlov, Ioannis Tomkos, Siddharth Sheth, Peter Winzer and James Kisner.

In turn, we would like to thank the publisher Todd Green at Elsevier for commissioning our book and for his help, and Charlotte Kent for her guidance and for keeping us on course. We are delighted that Elsevier’s Morgan Kaufmann is the publisher of our book.

We also thank Alice White who gave sage advice at the start of this project and Gudmund Knudsen, who graciously supported completing the book.

We would also like to add our own personal thanks.

I [Inniss] would like to thank Ovum, where I was employed when this project started. I am in debt to the wonderful analysts there who helped form the foundation for much of the story told here. I would also like to thank OFS, where I have been employed these last 12 months. While the opinions expressed here are mine alone and not those of my employer, my work at OFS has further helped inform me about the silicon photonics market, optical communication, and where silicon photonics can be a valuable technology. I am in debt to the organization for its generosity in allowing me to complete this manuscript.

As editor of Gazettabyte, I [Rubenstein] would also like to express my gratitude to the sponsors of Gazettabyte: ADVA Optical Networking, Ciena, Finisar, Infinera, Intel, LightCounting, Nokia, and Oclaro. Without such sponsors, many of whom have backed Gazettabyte since its start, the online publication would not exist. Through Gazettabyte, it has been possible to record the ongoing developments in datacom and telecom that have been a valuable resource in charting the progress of silicon photonics. Lastly, I have over the last 23 years interviewed individuals in the chip and telecoms industries. I am continually reminded of people’s generosity in taking time from their busy schedules to discuss technologies and markets. It is a wonderful privilege to have a front row seat on leading-edge products and technologies and to be briefed by experts. I would like to take this opportunity to thank them all.

Chapter 1

Silicon Photonics

Disruptive and Ready for Prime Time

Abstract

This chapter introduces silicon photonics and addresses its importance. Silicon photonics is not just another optical technology for high-speed communications—it will ultimately benefit both photonics and electronics. It is also a strategically important systems technology, reflected by the spate of vendor acquisitions of silicon photonics startups. This chapter also looks at the status of silicon photonics, whether it has reached its tipping point, and notable market opportunities. Lastly, the question of whether silicon photonics is a disruptive technology is answered.

Keywords

Silicon photonics; Moore’s law; indium phosphide; vertical-cavity surface-emitting lasers; disruptive technology; systems; disaggregated servers

This is the interesting thing about technology, you never really know how successful it will be.

Vladimir Kozlov [1]

There is a difference between a viable technology and the commercial application of it.

Mario Paniccia [2]

1.1 Introduction

In the 1950s the world welcomed the rise of the electronic transistor, which ultimately led to the popularization of the computer. In the 1990s optical technology enabled the exponential growth of data transmission, connecting computers globally, which gave rise to the democratization of the Internet and the World Wide Web. The next step in the journey of the digital economy—the application of optics to electronic processes and vice versa—is silicon photonics.

Optics—the use of light to send signals through a transparent path—is playing an increasingly important role in communications across a vast scale of distances. For two decades or more, it has allowed the networks of the telecommunications operators—the telcos—to cope with huge annual growth in data traffic. Now photonics is also playing a central role in the data center, where Internet data is received, processed, and distributed.

Silicon photonics can be viewed in several ways. From an optical component industry perspective, it is the most recent technology to join several established technologies used to make optical devices. This is a valid but narrow viewpoint, because silicon photonics is much more than that.

Silicon photonics enables optical devices to be made on a silicon substrate and fabricated in a chip facility. The resulting devices are starting to be adopted by the optical industry, but the technology’s commonalities with the much larger semiconductor industry is raising