the horizons of optical networks are much more than high
TRANSCRIPT
The horizons of optical networks are much more than high speed physical layer transport. An intelligent optical network design
must include higher network layer considerations. This is the only book currently on the market that addresses optical networks
from the physical layer to the network layer and should be valuable for those who try to understand the intricacies of what
optical networks can be.
—Vincent Chan, Professor, MIT Department of Electrical Engineering and Computer Science
This book is not only essential reading for anyone in the optical networks industry, it is important. It provides the necessary
foundation of learning for anyone hoping to contribute to this technology’s rapid evolution.
—Scott Clavenna, President, PointEast Research
The authors’ grasp of what is truly workable and worthwhile in optical networks is fundamental, and they have effectively
packaged this knowledge in an easy-to-comprehend text that will be valued to both veterans and those new to optical
networking.
—Scott Grout, President and CEO, Chorum Technologies
This is a comprehensive and authoritative work on optical networks, ranging in scope from components and systems to overall
design principles. I find the book well organized and easy to use, and I particularly like the treatment of network design and
operation. An essential book for anyone seriously interested in optical networks.
—Goff Hill, Chief Network Architect, Altamar Networks, UK
I really enjoy the bottoms-up approach taken by the authors to address fundamentals of optical components as the enablers,
optical transmission system design and engineering as the building blocks, and network architecture and its management
features that deliver applications to the network operators and services providers at the top of the food chain.
—Shoa-Kai Liu, Director of Advanced Technology, Worldcom
This book not only provides the fundamentals and details of photonics, but the pragmatic perspective presented enables
the service provider, the equipment manufacturer, and the academician to view light from a real-life standpoint.
—Mathew Oommen, Vice President, Network Architecture, Williams Communications Group
This book functions as both an introduction to optical networking and as a text to reference again and again. Great for system
designers as well as those marketing and selling those systems. Optical Networks provides theory and applications. While no
text can be truly state-of-the-art in the fast moving area of optical networking, this one comes as close as possible.
—Alan Repech, System Architect, Cisco Systems Optical Transport
This book provides the most comprehensive coverage of both the theory and practice of optical networking. Its up-
to-date coverage makes it an invaluable reference for both practitioners and researchers.
—Suresh Subramaniam, Assistant Professor, Department of Electrical and Computer Engineering, George Washington
University
This book provides an excellent overview of the complex field of optical networking. I especially like how it ties the optical
hardware functionality into the overall networking picture. Everybody who wants to be a player in the optical networking space
should have this book within easy reach.
—Martin Zirngibl, Director, Photonics Network Research, Lucent Technologies, Bell Laboratories
The Morgan Kaufmann Series in Networking Series Editor, David Clark, M.I.T. P2P Networking and Applications John Buford, Heather Yu, and Eng Lua The Illustrated Network Walter Goralski Broadband Cable Access Networks: The HFC Plant David Large and James Farmer Technical, Commercial and Regulatory Challenges of QoS: An Internet Service Model Perspective XiPeng Xiao MPLS: Next Steps Bruce S. Davie and Adrian Farrel Wireless Networking Anurag Kumar, D. Manjunath, and Joy Kuri Internet Multimedia Communications Using SIP Rogelio Martinez Perea Information Assurance: Dependability and Security in Networked Systems Yi Qian, James Joshi, David Tipper, and Prashant Krishnamurthy Network Analysis, Architecture, and Design, 3e James D. McCabe Wireless Communications & Networking: An Introduction Vijay K. Garg IPv6 Advanced Protocols Implementation Qing Li, Tatuya Jinmei, and Keiichi Shima Computer Networks: A Systems Approach, 4e Larry L. Peterson and Bruce S. Davie Network Routing: Algorithms, Protocols, and Architectures Deepankar Medhi and Karthikeyan Ramaswami Deploying IP and MPLS QoS for Multiservice Networks: Theory and Practice John Evans and Clarence Filsfils
Traffic Engineering and QoS Optimization of Integrated Voice & Data Networks Gerald R. Ash IPv6 Core Protocols Implementation Qing Li, Tatuya Jinmei, and Keiichi Shima Smart Phone and Next-Generation Mobile Computing Pei Zheng and Lionel Ni GMPLS: Architecture and Applications Adrian Farrel and Igor Bryskin Content Networking: Architecture, Protocols, and Practice Markus Hofmann and Leland R. Beaumont Network Algorithmics: An Interdisciplinary Approach to Designing Fast Networked Devices George Varghese Network Recovery: Protection and Restoration of Optical, SONET-SDH, IP, and MPLS Jean Philippe Vasseur, Mario Pickavet, and Piet Demeester Routing, Flow, and Capacity Design in Communication and Computer Networks Michał Pióro and Deepankar Medhi Wireless Sensor Networks: An Information Processing Approach Feng Zhao and Leonidas Guibas Communication Networking: An Analytical Approach Anurag Kumar, D. Manjunath, and Joy Kuri The Internet and Its Protocols: A Comparative Approach Adrian Farrel Modern Cable Television Technology: Video, Voice, and Data Communications, 2e Walter Ciciora, James Farmer, David Large, and Michael Adams Policy-Based Network Management: Solutions for the Next Generation John Strassner MPLS Network Management: MIBs, Tools, and Techniques Thomas D. Nadeau Developing IP-Based Services: Solutions for Service Providers and Vendors Monique Morrow and Kateel Vijayananda
Telecommunications Law in the Internet Age Sharon K. Black Optical Networks: A Practical Perspective, 3e Rajiv Ramaswami, Kumar N. Sivarajan, and Galen Sasaki Internet QoS: Architectures and Mechanisms Zheng Wang TCP/IP Sockets in Java: Practical Guide for Programmers Michael J. Donahoo and Kenneth L. Calvert TCP/IP Sockets in C: Practical Guide for Programmers Kenneth L. Calvert and Michael J. Donahoo Multicast Communication: Protocols, Programming, and Applications Ralph Wittmann and Martina Zitterbart High-Performance Communication Networks, 2e Jean Walrand and Pravin Varaiya Internetworking Multimedia Jon Crowcroft, Mark Handley, and Ian Wakeman Understanding Networked Applications: A First Course David G. Messerschmitt Integrated Management of Networked Systems: Concepts, Architectures, and their Operational Application Heinz-Gerd Hegering, Sebastian Abeck, and Bernhard Neumair Virtual Private Networks: Making the Right Connection Dennis Fowler Networked Applications: A Guide to the New Computing Infrastructure David G. Messerschmitt Wide Area Network Design: Concepts and Tools for Optimization Robert S. Cahn For further information on these books and for a list of forthcoming titles, please visit our Web site at http://www.mkp.com.
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Printed in the United States of America
09 10 11 12 13 5 4 3 2 1
To Our Parents
Optical Networks
A Practical Perspective
Third Edition
Rajiv Ramaswami
Kumar N. Sivarajan
Galen H. Sasaki
AMSTERDAM • BOSTON • HEIDELBERG • LONDON
NEW YORK • OXFORD • PARIS • SAN DIEGO
SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO
Morgan Kaufmann Publishers is an imprint of Elsevier
Contents
Foreword xxi
Preface to the First Edition xxv
Preface to the Second Edition xxix
Preface to the Current Edition xxxiii
1 Introduction to Optical Networks 1
1.1 Telecommunications Network Architecture . . . . . . . . . . . . . . . . . . . . . 2
1.2 Services, Circuit Switching, and Packet Switching . . . . . . . . . . . . . . . . . 5
1.2.1 The Changing Services Landscape . . . . . . . . . . . . . . . . . . . . . 8
1.3 Optical Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.3.1 Multiplexing Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.3.2 Second-Generation Optical Networks . . . . . . . . . . . . . . . . . . . 13
1.4 The Optical Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.5 Transparency and All-Optical Networks . . . . . . . . . . . . . . . . . . . . . . 22
1.6 Optical Packet Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.7 Transmission Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.7.1 Wavelengths, Frequencies, and Channel Spacing . . . . . . . . . . . . . 26
1.7.2 Wavelength Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.7.3 Optical Power and Loss . . . . . . . . . . . . . . . . . . . . . . . . . . 29
1.8 Network Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
ix
x Contents
1.8.1 Early Days—Multimode Fiber . . . . . . . . . . . . . . . . . . . . . . . 30
1.8.2 Single-Mode Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
1.8.3 Optical Amplifiers and WDM . . . . . . . . . . . . . . . . . . . . . . . 34
1.8.4 Beyond Transmission Links to Networks . . . . . . . . . . . . . . . . . 37
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
I Technology 45
2 Propagation of Signals in Optical Fiber 47
2.1 Loss and Bandwidth Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
2.1.1 Bending Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.2 Intermodal Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.2.1 Geometrical Optics Approach . . . . . . . . . . . . . . . . . . . . . . . 52
2.2.2 Bit Rate–Distance Limitation . . . . . . . . . . . . . . . . . . . . . . . . 54
2.2.3 Controlling Intermodal Dispersion: Graded-Index Multimode Fiber . . 55
2.2.4 Multimode Fiber in Practice . . . . . . . . . . . . . . . . . . . . . . . . 57
2.3 Optical Fiber as a Waveguide . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
2.3.1 Wave Theory Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 59
2.3.2 Fiber Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
2.3.3 Polarization Modes and Polarization-Mode Dispersion . . . . . . . . . 65
2.3.4 Other Waveguides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
2.4 Chromatic Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
2.4.1 Chirped Gaussian Pulses . . . . . . . . . . . . . . . . . . . . . . . . . . 71
2.4.2 Controlling the Dispersion: Dispersion-Shifted Fibers . . . . . . . . . . 75
2.5 Nonlinear Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
2.5.1 Effective Length and Area . . . . . . . . . . . . . . . . . . . . . . . . . 79
2.5.2 Stimulated Brillouin Scattering . . . . . . . . . . . . . . . . . . . . . . . 81
2.5.3 Stimulated Raman Scattering . . . . . . . . . . . . . . . . . . . . . . . . 82
2.5.4 Propagation in a Nonlinear Medium . . . . . . . . . . . . . . . . . . . 83
2.5.5 Self-Phase Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
2.5.6 SPM-Induced Chirp for Gaussian Pulses . . . . . . . . . . . . . . . . . . 88
2.5.7 Cross-Phase Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . 90
2.5.8 Four-Wave Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
2.5.9 Fiber Types to Mitigate Nonlinear Effects . . . . . . . . . . . . . . . . . 95
2.6 Solitons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
2.6.1 Dispersion-Managed Solitons . . . . . . . . . . . . . . . . . . . . . . . 102
2.7 Other Fiber Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Contents xi
2.7.1 Photonic Crystal Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
2.7.2 Plastic Optical Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
3 Components 113
3.1 Couplers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
3.1.1 Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
3.1.2 Conservation of Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
3.2 Isolators and Circulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
3.2.1 Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
3.3 Multiplexers and Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
3.3.1 Gratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
3.3.2 Diffraction Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
3.3.3 Bragg Gratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
3.3.4 Fiber Gratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
3.3.5 Fabry-Perot Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
3.3.6 Multilayer Dielectric Thin-Film Filters . . . . . . . . . . . . . . . . . . . 139
3.3.7 Mach-Zehnder Interferometers . . . . . . . . . . . . . . . . . . . . . . . 141
3.3.8 Arrayed Waveguide Grating . . . . . . . . . . . . . . . . . . . . . . . . 145
3.3.9 Acousto-Optic Tunable Filter . . . . . . . . . . . . . . . . . . . . . . . 149
3.3.10 High Channel Count Multiplexer Architectures . . . . . . . . . . . . . 154
3.4 Optical Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
3.4.1 Stimulated Emission . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
3.4.2 Spontaneous Emission . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
3.4.3 Erbium-Doped Fiber Amplifiers . . . . . . . . . . . . . . . . . . . . . . 160
3.4.4 Raman Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
3.4.5 Semiconductor Optical Amplifiers . . . . . . . . . . . . . . . . . . . . . 167
3.4.6 Crosstalk in SOAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
3.5 Transmitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
3.5.1 Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
3.5.2 Light-Emitting Diodes . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
3.5.3 Tunable Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
3.5.4 Direct and External Modulation . . . . . . . . . . . . . . . . . . . . . . 192
3.5.5 Pump Sources for Raman Amplifiers . . . . . . . . . . . . . . . . . . . . 196
3.6 Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
3.6.1 Photodetectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
3.6.2 Front-End Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
xii Contents
3.7 Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
3.7.1 Large Optical Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
3.7.2 Optical Switch Technologies . . . . . . . . . . . . . . . . . . . . . . . . 213
3.7.3 Large Electronic Switches . . . . . . . . . . . . . . . . . . . . . . . . . . 220
3.8 Wavelength Converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
3.8.1 Optoelectronic Approach . . . . . . . . . . . . . . . . . . . . . . . . . . 222
3.8.2 Optical Gating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
3.8.3 Interferometric Techniques . . . . . . . . . . . . . . . . . . . . . . . . . 225
3.8.4 Wave Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
4 Modulation and Demodulation 245
4.1 Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245
4.1.1 Signal Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246
4.2 Subcarrier Modulation and Multiplexing . . . . . . . . . . . . . . . . . . . . . . 248
4.2.1 Clipping and Intermodulation Products . . . . . . . . . . . . . . . . . . 249
4.2.2 Applications of SCM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
4.3 Spectral Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
4.3.1 Optical Duobinary Modulation . . . . . . . . . . . . . . . . . . . . . . 252
4.3.2 Optical Single Sideband Modulation . . . . . . . . . . . . . . . . . . . . 254
4.3.3 Multilevel Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
4.3.4 Capacity Limits of Optical Fiber . . . . . . . . . . . . . . . . . . . . . . 255
4.4 Demodulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
4.4.1 An Ideal Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
4.4.2 A Practical Direct Detection Receiver . . . . . . . . . . . . . . . . . . . 259
4.4.3 Front-End Amplifier Noise . . . . . . . . . . . . . . . . . . . . . . . . . 260
4.4.4 APD Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
4.4.5 Optical Preamplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
4.4.6 Bit Error Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264
4.4.7 Coherent Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
4.4.8 Timing Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
4.4.9 Equalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
4.5 Error Detection and Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
4.5.1 Reed-Solomon Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
4.5.2 Interleaving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279
Contents xiii
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
5 Transmission System Engineering 289
5.1 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
5.2 Power Penalty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
5.3 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292
5.4 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
5.5 Optical Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
5.5.1 Gain Saturation in EDFAs . . . . . . . . . . . . . . . . . . . . . . . . . 296
5.5.2 Gain Equalization in EDFAs . . . . . . . . . . . . . . . . . . . . . . . . 297
5.5.3 Amplifier Cascades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
5.5.4 Amplifier Spacing Penalty . . . . . . . . . . . . . . . . . . . . . . . . . 300
5.5.5 Power Transients and Automatic Gain Control . . . . . . . . . . . . . . 302
5.5.6 Lasing Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
5.6 Crosstalk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304
5.6.1 Intrachannel Crosstalk . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
5.6.2 Interchannel Crosstalk . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
5.6.3 Crosstalk in Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
5.6.4 Bidirectional Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
5.6.5 Crosstalk Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
5.6.6 Cascaded Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
5.7 Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
5.7.1 Chromatic Dispersion Limits: NRZ Modulation . . . . . . . . . . . . . 315
5.7.2 Chromatic Dispersion Limits: RZ Modulation . . . . . . . . . . . . . . 317
5.7.3 Dispersion Compensation . . . . . . . . . . . . . . . . . . . . . . . . . 320
5.7.4 Polarization-Mode Dispersion (PMD) . . . . . . . . . . . . . . . . . . . 325
5.8 Fiber Nonlinearities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328
5.8.1 Effective Length in Amplified Systems . . . . . . . . . . . . . . . . . . . 329
5.8.2 Stimulated Brillouin Scattering . . . . . . . . . . . . . . . . . . . . . . . 331
5.8.3 Stimulated Raman Scattering . . . . . . . . . . . . . . . . . . . . . . . . 332
5.8.4 Four-Wave Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
5.8.5 Self-/Cross-Phase Modulation . . . . . . . . . . . . . . . . . . . . . . . 338
5.8.6 Role of Chromatic Dispersion Management . . . . . . . . . . . . . . . 340
5.9 Wavelength Stabilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
5.10 Design of Soliton Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
5.11 Design of Dispersion-Managed Soliton Systems . . . . . . . . . . . . . . . . . . 343
5.12 Overall Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
5.12.1 Fiber Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
5.12.2 Transmit Power and Amplifier Spacing . . . . . . . . . . . . . . . . . . 348
xiv Contents
5.12.3 Chromatic Dispersion Compensation . . . . . . . . . . . . . . . . . . . 348
5.12.4 Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
5.12.5 Nonlinearities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
5.12.6 Interchannel Spacing and Number of Wavelengths . . . . . . . . . . . . 349
5.12.7 All-Optical Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
5.12.8 Wavelength Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
5.12.9 Transparency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
II Networks 367
6 Client Layers of the Optical Layer 369
6.1 SONET/SDH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
6.1.1 Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
6.1.2 VCAT and LCAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
6.1.3 SONET/SDH Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
6.1.4 SONET Frame Structure . . . . . . . . . . . . . . . . . . . . . . . . . . 379
6.1.5 SONET/SDH Physical Layer . . . . . . . . . . . . . . . . . . . . . . . . 384
6.1.6 Elements of a SONET/SDH Infrastructure . . . . . . . . . . . . . . . . 386
6.2 Optical Transport Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
6.2.1 Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
6.2.2 Frame Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
6.2.3 Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
6.3 Generic Framing Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
6.4 Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
6.4.1 Frame Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
6.4.2 Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403
6.4.3 Ethernet Physical Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . 406
6.4.4 Carrier Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
6.5 IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
6.5.1 Routing and Forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . 413
6.5.2 Quality of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
6.6 Multiprotocol Label Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
6.6.1 Labels and Forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
6.6.2 Quality of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
6.6.3 Signaling and Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
Contents xv
6.6.4 Carrier Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
6.7 Resilient Packet Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
6.7.1 Quality of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
6.7.2 Node Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
6.7.3 Fairness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
6.8 Storage-Area Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
6.8.1 Fibre Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 428
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
7 WDM Network Elements 433
7.1 Optical Line Terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436
7.2 Optical Line Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
7.3 Optical Add/Drop Multiplexers . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
7.3.1 OADM Architectures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
7.3.2 Reconfigurable OADMs . . . . . . . . . . . . . . . . . . . . . . . . . . 447
7.4 Optical Crossconnects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452
7.4.1 All-Optical OXC Configurations . . . . . . . . . . . . . . . . . . . . . . 458
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
8 Control and Management 469
8.1 Network Management Functions . . . . . . . . . . . . . . . . . . . . . . . . . . 469
8.1.1 Management Framework . . . . . . . . . . . . . . . . . . . . . . . . . . 471
8.1.2 Information Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473
8.1.3 Management Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . 474
8.2 Optical Layer Services and Interfacing . . . . . . . . . . . . . . . . . . . . . . . 476
8.3 Layers within the Optical Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
8.4 Multivendor Interoperability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479
8.5 Performance and Fault Management . . . . . . . . . . . . . . . . . . . . . . . . 481
8.5.1 The Impact of Transparency . . . . . . . . . . . . . . . . . . . . . . . . 481
8.5.2 BER Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482
8.5.3 Optical Trace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
8.5.4 Alarm Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
8.5.5 Data Communication Network (DCN) and Signaling . . . . . . . . . . 485
8.5.6 Policing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
xvi Contents
8.5.7 Optical Layer Overhead . . . . . . . . . . . . . . . . . . . . . . . . . . 487
8.5.8 Client Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
8.6 Configuration Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
8.6.1 Equipment Management . . . . . . . . . . . . . . . . . . . . . . . . . . 493
8.6.2 Connection Management . . . . . . . . . . . . . . . . . . . . . . . . . . 494
8.6.3 Adaptation Management . . . . . . . . . . . . . . . . . . . . . . . . . . 499
8.7 Optical Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
8.7.1 Open Fiber Control Protocol . . . . . . . . . . . . . . . . . . . . . . . . 503
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508
9 Network Survivability 511
9.1 Basic Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 513
9.2 Protection in SONET/SDH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518
9.2.1 Point-to-Point Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . 518
9.2.2 Self-Healing Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 521
9.2.3 Unidirectional Path-Switched Rings . . . . . . . . . . . . . . . . . . . . 523
9.2.4 Bidirectional Line-Switched Rings . . . . . . . . . . . . . . . . . . . . . 525
9.2.5 Ring Interconnection and Dual Homing . . . . . . . . . . . . . . . . . . 530
9.3 Protection in the Client Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 532
9.3.1 Protection in Resilient Packet Rings . . . . . . . . . . . . . . . . . . . . 533
9.3.2 Protection in Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534
9.3.3 Protection in IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
9.3.4 Protection in MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
9.4 Why Optical Layer Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
9.4.1 Service Classes Based on Protection . . . . . . . . . . . . . . . . . . . . 548
9.5 Optical Layer Protection Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . 549
9.5.1 1 + 1 OMS Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . 552
9.5.2 1:1 OMS Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552
9.5.3 OMS-DPRing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552
9.5.4 OMS-SPRing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553
9.5.5 1:N Transponder Protection . . . . . . . . . . . . . . . . . . . . . . . . 553
9.5.6 1 + 1 OCh Dedicated Protection . . . . . . . . . . . . . . . . . . . . . . 553
9.5.7 OCh-SPRing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557
9.5.8 OCh-Mesh Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . 557
9.5.9 GMPLS Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563
9.6 Interworking between Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 564
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 565
Contents xvii
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569
10 WDM Network Design 573
10.1 Cost Trade-Offs: A Detailed Ring Network Example . . . . . . . . . . . . . . . 577
10.2 LTD and RWA Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584
10.2.1 Lightpath Topology Design . . . . . . . . . . . . . . . . . . . . . . . . . 585
10.2.2 Routing and Wavelength Assignment . . . . . . . . . . . . . . . . . . . 590
10.2.3 Wavelength Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . 593
10.3 Dimensioning Wavelength-Routing Networks . . . . . . . . . . . . . . . . . . . 596
10.4 Statistical Dimensioning Models . . . . . . . . . . . . . . . . . . . . . . . . . . . 599
10.4.1 First-Passage Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600
10.4.2 Blocking Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
10.5 Maximum Load Dimensioning Models . . . . . . . . . . . . . . . . . . . . . . . 609
10.5.1 Offline Lightpath Requests . . . . . . . . . . . . . . . . . . . . . . . . . 610
10.5.2 Online RWA in Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 615
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 619
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623
11 Access Networks 629
11.1 Network Architecture Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 631
11.2 Enhanced HFC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 636
11.3 Fiber to the Curb (FTTC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 638
11.3.1 PON Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 648
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651
12 Photonic Packet Switching 653
12.1 Optical Time Division Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . . 658
12.1.1 Bit Interleaving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 660
12.1.2 Packet Interleaving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 661
12.1.3 Optical AND Gates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665
12.2 Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 668
12.2.1 Tunable Delays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 670
12.2.2 Optical Phase Lock Loop . . . . . . . . . . . . . . . . . . . . . . . . . . 671
xviii Contents
12.3 Header Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 673
12.4 Buffering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674
12.4.1 Output Buffering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 676
12.4.2 Input Buffering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 677
12.4.3 Recirculation Buffering . . . . . . . . . . . . . . . . . . . . . . . . . . . 678
12.4.4 Using Wavelengths for Contention Resolution . . . . . . . . . . . . . . 680
12.4.5 Deflection Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 683
12.5 Burst Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 688
12.6 Testbeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 689
12.6.1 KEOPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 690
12.6.2 NTT’s Optical Packet Switches . . . . . . . . . . . . . . . . . . . . . . . 691
12.6.3 BT Labs Testbeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693
12.6.4 Princeton University Testbed . . . . . . . . . . . . . . . . . . . . . . . . 693
12.6.5 AON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694
12.6.6 CORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 696
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 696
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 698
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 699
13 Deployment Considerations 707
13.1 The Evolving Telecommunications Network . . . . . . . . . . . . . . . . . . . . 707
13.1.1 The SONET/SDH Core Network . . . . . . . . . . . . . . . . . . . . . 709
13.1.2 Architectural Choices for Next-Generation Transport Networks . . . . 712
13.2 Designing the Transmission Layer . . . . . . . . . . . . . . . . . . . . . . . . . . 718
13.2.1 Using SDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 719
13.2.2 Using TDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 720
13.2.3 Using WDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 721
13.2.4 Unidirectional versus Bidirectional WDM Systems . . . . . . . . . . . . 722
13.2.5 Long-Haul Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 724
13.2.6 Long-Haul Network Case Study . . . . . . . . . . . . . . . . . . . . . . 725
13.2.7 Long-Haul Undersea Networks . . . . . . . . . . . . . . . . . . . . . . 732
13.2.8 Metro Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 734
13.2.9 Metro Ring Case Study . . . . . . . . . . . . . . . . . . . . . . . . . . . 736
13.2.10 From Opaque Links to Agile All-Optical Networks . . . . . . . . . . . 738
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 739
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 740
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744
Contents xix
A Acronyms 747
B Symbols and Parameters 757
C Standards 761
C.1 International Telecommunications Union (ITU-T) . . . . . . . . . . . . . . . . . 761
C.1.1 Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 761
C.1.2 SDH (Synchronous Digital Hierarchy) . . . . . . . . . . . . . . . . . . . 761
C.1.3 Optical Networking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762
C.1.4 Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762
C.2 Telcordia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763
C.2.1 Physical and Environmental . . . . . . . . . . . . . . . . . . . . . . . . 763
C.2.2 SONET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763
C.2.3 Optical Networking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 764
C.3 American National Standards Institute (ANSI) . . . . . . . . . . . . . . . . . . . 764
C.3.1 SONET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 764
C.3.2 Fibre Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 764
D Wave Equations 765
E Pulse Propagation in Optical Fiber 769
E.1 Propagation of Chirped Gaussian Pulses . . . . . . . . . . . . . . . . . . . . . . 772
E.2 Nonlinear Effects on Pulse Propagation . . . . . . . . . . . . . . . . . . . . . . . 773
E.3 Soliton Pulse Propagation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 776
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777
F Nonlinear Polarization 779
G Multilayer Thin-Film Filters 781
G.1 Wave Propagation at Dielectric Interfaces . . . . . . . . . . . . . . . . . . . . . . 781
G.2 Filter Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 785
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788
H Random Variables and Processes 789
H.1 Random Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789
H.1.1 Gaussian Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 790
H.1.2 Maxwell Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
H.1.3 Poisson Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
H.2 Random Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 792
H.2.1 Poisson Random Process . . . . . . . . . . . . . . . . . . . . . . . . . . 793
xx Contents
H.2.2 Gaussian Random Process . . . . . . . . . . . . . . . . . . . . . . . . . 794
Further Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794
I Receiver Noise Statistics 795
I.1 Shot Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
I.2 Amplifier Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800
J Asynchronous Transfer Mode 801
J.1 Functions of ATM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 802
J.1.1 Connections and Cell Forwarding . . . . . . . . . . . . . . . . . . . . . 803
J.1.2 Virtual Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804
J.2 Adaptation Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
J.2.1 AAL-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 805
J.2.2 AAL-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
J.3 Quality of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 806
J.4 Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807
J.5 Signaling and Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807
Bibliography 809
Index 845
Foreword
by Paul E. Green, Jr.
Director, Optical Network Technology
Tellabs, Inc.
Not too many years ago, whenever one wanted to send messages effectively, there
were really only two choices—send them by wire or send them by radio. This situation
lasted for decades until the mid-1960s, when the fiber optics revolution began, quietly
at first, and then with increasing force as people began to appreciate that sending
pulses of light through tiny strands of glass wasn’t so crazy after all. This revolution
is now in full cry, with 4000 strand miles of fiber being installed per day, just
in the United States alone. Fiber has been displacing wire in many applications,
and gradually it is emerging as one of the two dominant Cinderella transmission
technologies of today, wireless being the other. One of these (wireless) goes anywhere
but doesn’t do much when it gets there, whereas the other (fiber) will never go
everywhere but does a great deal indeed wherever it reaches. From the earliest days
of fiber communication, people realized that this simple glass medium has incredible
amounts of untapped bandwidth capacity waiting to be mined, should the day come
when we would actually need it, and should we be able to figure out how to tap it.
That day has now come. The demand is here and so are the solutions.
This book describes a revolution within a revolution, the opening up of the
capacity of the now-familiar optical fiber to carry more messages, handle a wider
variety of transmission types, and provide improved reliabilities and ease of use.
In many places where fiber has been installed simply as a better form of copper,
even the gigabit capacities that result have not proved adequate to keep up with
the demand. The inborn human voracity for more and more bandwidth, plus the
growing realization that there are other flexibilities to be had by imaginative use of
the fiber, have led people to explore all-optical networks, the subject of this book.
xxi
xxii Foreword
Such networks are those in which either wavelength division or time division is used
in new ways to form entire network structures where the messages travel in purely
optical form all the way from one user location to another.
When I attempted the same kind of book in 1993, nobody was quite sure whether
optical networking would be a roaring success or disappear into the annals of “what-
ever happened to . . .” stories of technology that had once sounded great on paper,
but that had somehow never panned out in the real world. My book (Fiber Optic
Networks, Prentice Hall) spent most of its pages talking about technology building
blocks and lamenting their limitations since there was little to say about real net-
works, the architectural considerations underlying them, and what good they had
ever done anybody.
In the last four years, optical networking has indeed really happened, essentially
all of it based on wavelength division multiplexing, and with this book Ramaswami
and Sivarajan, two of the principal architects of this success, have redressed the
insufficiencies of earlier books such as mine. Today, hundreds of millions of dol-
lars of wavelength division networking systems are being sold annually, major new
businesses have been created that produce nothing but optical networks, and band-
width bottlenecks are being relieved and proliferating protocol zoos tamed by this
remarkably transparent new way of doing networking; what’s more, there is a rich
architectural understanding of where to go next. Network experts, fresh from the
novelties of such excitements as the Web, now have still another wonderful toy shop
to play in. The whole optical networking idea is endlessly fascinating in itself—based
on a medium with thousands of gigabits of capacity yet so small as to be almost in-
visible, transmitters no larger than a grain of salt, amplifiers that amplify vast chunks
of bandwidth purely as light, transmission designs that bypass 50 years of hard-won
but complex coding, modulation and equalization insights, network architectures
that subsume many functions usually done more clumsily in the lower layers of clas-
sical layered architectures—these are all fresh and interesting topics that await the
reader of this book.
To understand this new networking revolution within a revolution, it is neces-
sary to be led with a sure hand through territory that to many will be unfamiliar.
The present authors, with their rare mixture of physics and network architecture
expertise, are eminently qualified to serve as guides. After spending some time with
this book, you will be more thoroughly conversant with all the important issues that
today affect how optical networks are made, what their limitations and potentialities
are, and how they fit in with more classical forms of communication networks based
on electronic time division. Whether you are a computer network expert wondering
how to use fiber to break the bandwidth bottlenecks that are limiting your system ca-
pabilities, a planner or implementer trying to future-proof your telephone network,
Foreword xxiii
a teacher planning a truly up-to-date communication engineering curriculum, a stu-
dent looking for a fun lucrative career, or a midcareer person in need of a retread,
this volume will provide the help you need.
The authors have captured what is going on and what is going to be going on in
this field in a completely up-to-date treatment unavailable elsewhere. I learned a lot
from reading it and expect that you will too.
Preface to the First
Edition
Fiber optics has become the core of our telecommunications and data networking
infrastructures. Optical fiber is the preferred means of transmission for any data over
a few tens of megabits per second and over anything from a kilometer and upwards.
The first generation of fiber optic networks used optical fiber predominantly as a re-
placement for copper cable for transmission at higher bit rates over longer distances.
The second generation of fiber optic networks is just emerging. These networks re-
ally exploit the capacity of fiber to achieve overall transmission capacities of several
tens of gigabits per second to terabits per second. Moreover, they exploit routing
and switching of signals in the optical domain. The rapid evolution of technology,
coupled with the insatiable demand for bandwidth, is resulting in a rapid transition
of these networks from research laboratories into the marketplace.
The fundamentals of optical fiber transmission are covered well in several
books. There is, however, a need for a book that covers the transmission aspects
of second-generation fiber optic networks, and focuses on the networking aspects
such as architectures, and control and management issues. Such a book would not
be complete without describing the components needed to build these networks, par-
ticularly since the network architectures strongly depend on these components, and
a person designing optical networks will need to be familiar with their capabilities.
Thus this book attempts to cover components, transmission, and networking issues
related to second-generation optical networks. It is targeted at professionals who are
network planners, designers or operators, graduate students in electrical engineering
and computer science, and engineers wanting to learn about optical networks.
xxv
xxvi Preface to the First Edition
Teaching and Learning from This Book
This book can be used as a textbook for graduate courses in electrical engineer-
ing or computer science. Much of the material in this book has been covered in
courses taught by us. Part I covers components and transmission technology aspects
of optical networking, and Part II deals with the networking aspects. To understand
the networking issues in Part II, students will require a basic undergraduate-level
knowledge of communication networks and probability. We have tried to make the
transmission-related chapters in Part I of the book accessible to networking profes-
sionals. For example, components are treated first in a simple qualitative manner
from the viewpoint of a network designer, but their principle of operation is then
explained in detail. Some prior knowledge of electromagnetics will be useful in un-
derstanding the detailed quantitative treatment in some of the sections. Advanced
sections are marked by an asterisk; these sections can be omitted without loss of
continuity.
With this background, the book can be the basis for a graduate course in an elec-
trical engineering curriculum. Alternatively, a graduate course in a computer science
department might emphasize network architectures and control and management,
by focusing on Part II, and skim over the technology portions of the book in Part
I. Likewise, a course on optical transmission in an electrical engineering department
might instead focus on Part I and omit the remaining chapters. Each chapter is ac-
companied by a number of problems, and instructors may obtain a solution manual
by contacting the publisher at [email protected].
Second, we have attempted to provide an overview of much recent work in
this emerging field, so as to make the book useful to researchers in the field as an
up-to-date reference. Each chapter includes an extensive list of references for those
who might wish to explore further. The problems include some research topics for
further exploration as well. Finally, we hope that the book will also serve as an
introduction to people working in other areas who wish to become familiar with
fiber optics.
Overview of the Book
Chapter 1 offers an introduction to optical networks. Part I of the book is devoted
to the technology underlying optical networks. Chapter 2 describes how light prop-
agates in optical fiber, and deals with the phenomena of loss, dispersion, and fiber
nonlinearities, which play a major role in the design of transmission systems. Chap-
ter 3 provides an overview of the different components needed to build a network,
such as transmitters, receivers, multiplexers, and switches. Chapter 4 describes how
Preface to the First Edition xxvii
electrical signals are converted to light signals (the modulation process) at the trans-
mitter and how they are recovered at the receiver (demodulation). Chapter 5 focuses
on the physical layer design of the latest generation of transmission systems and
networks, and the factors limiting the system performance.
Part II is devoted to a variety of networking aspects of optical networks. Chap-
ter 6 describes the different first-generation optical networks that are deployed widely
today. Chapter 7 covers broadcast and select WDM networks that are suitable for
LANs and MANs. Different topologies, media-access, and scheduling methods will
be described and compared in a uniform framework. Chapter 8 describes networks
using wavelength routing. These networks are emerging from the laboratories into
commercial deployment. The chapter covers the architectural aspects of these net-
works and focuses on the key design issues. Chapter 9 describes how to overlay virtual
networks, for example, IP or ATM networks over an underlying second-generation
optical network. Chapter 10 covers control and management, including connection
management, fault management, and safety management. Chapter 11 describes sev-
eral significant experimental wavelength routing demonstrations, field trials, and pro-
totypes. Chapter 12 describes passive optical network solutions for fiber-to-the-curb
and fiber-to-the-home access network applications. Chapter 13 covers the issues as-
sociated with deploying the new second-generation technology in different types of
telecommunications networks. Chapter 14 covers optical time division multiplexed
networks, which are today in the research labs but offer future potential for trans-
mission at very high rates on each WDM channel.
The appendices cover some of the basics of stochastic processes and graph theory
for readers as background material for the book. The large number of symbols and
parameters used in Part I (Technology) is also summarized in an appendix.
Acknowledgments
First and foremost, we would like to thank Paul Green for introducing us to this
field and being our mentor over the years, as well as for writing the foreword to this
book. We would like to acknowledge, in particular, Rick Barry, Ori Gerstel, Ashish
Vengsarkar, Weyl-Kuo Wang, and Chaoyu Yue for their detailed reviews and discus-
sions of part or all of the material in the book. In addition, we would like to thank
Venkat Anatharam, Dan Blumenthal, Kamal Goel, Karen Liu, Roger Merel, Rick
Neuner, and Niall Robinson for their comments. We would also like to thank Rajesh
M. Krishnaswamy for performing one of the simulations in Section 10.2.2, A. Sel-
varajan for answering some of our technology-related questions, and Chandrika
Sridhar for helping with the preparation of the solutions manual.
xxviii Preface to the First Edition
We would also like to thank the folks at Morgan Kaufmann; in particular, our
editor, Jennifer Mann, for guiding us through the entire process from start to finish
and for her efforts to improve the quality of our book, and our production editor,
Cheri Palmer, for orchestrating the production of the book.
Finally, we’d like to acknowledge the invaluable support given to us by our wives,
Uma and Vinu, during this endeavor, and to Uma for drawing many of the figures in
the book.
Preface to the Second
Edition
Since the first edition of this book appeared in February 1998, we have witnessed a
dramatic explosion in optical networking. Optical networking used to be confined
to a fairly small community of researchers and engineers but is now of great interest
to a broad audience including students; engineers in optical component, equipment,
and service provider companies; network planners; investors; venture capitalists; and
industry and investment analysts.
With the rapid pace in technological advances and the widespread deployment of
optical networks over the past three years, the need for a second edition of this book
became apparent. In this edition we have attempted to include the latest advances in
optical networks and their underlying technologies. We have also tried to make the
book more accessible to a broader community of people interested in learning about
optical networking. With this in mind, we have rewritten several chapters, added a
large amount of new material, and removed some material that is not as relevant
to practical optical networks. We have also updated the references and added some
new problems.
The major changes we’ve made are as follows: We have mostly rewritten the
introduction to reflect the current understanding of optical networks, and we’ve
added a section called “Transmission Basics” to introduce several terms commonly
used in optical networking and wavelength division multiplexing (WDM) to the
layperson.
In Chapter 2, we’ve added significant sections on dispersion management and
solitons, along with a section describing the different fiber types now available.
xxix
xxx Preface to the Second Edition
In Chapter 3, we now cover electro-absorption modulated lasers, tunable lasers,
Raman amplifiers, and L-band erbium-doped fiber amplifiers, and we have signifi-
cantly expanded the section on optical switching to include the new types of switches
using micro-electro-mechanical systems (MEMS) and other technologies.
In Chapter 4, we cover return-to-zero modulation and other newer modulation
formats such as duobinary, as well as forward error correction, now widely used in
high-bit-rate systems. Chapter 5 now includes expanded coverage of chromatic dis-
persion and polarization effects, which are important factors influencing the design
of high-bit-rate long-haul systems.
The networking chapters of the book have been completely rewritten and ex-
panded to reflect the signficant progress made in this area. We have organized these
chapters as follows: Chapter 6 now includes expanded coverage of SONET/SDH,
ATM, and IP networks. Chapter 7 is devoted to architectural considerations un-
derlying WDM network elements. Chapter 8 attempts to provide a unified view
of the problems associated with network design and routing in optical networks.
Chapter 9 provides significantly expanded coverage of network management and
control. We have devoted Chapter 10 to network survivability, with a detailed
discussion on optical layer protection. Chapter 11 covers access networks with
a focus on emerging passive optical networks (PONs). Chapter 12 provides up-
dated coverage of optical packet-switched networks. Finally, Chapter 13 focuses
on deployment considerations and is intended to provide the reader with a broad
understanding of how telecommunications networks are evolving. It includes a cou-
ple of detailed network planning case studies on a typical long-haul and metro
network.
There is currently a great deal of standards activity in this field. We’ve added an
appendix listing the relevant standards. We have also added another appendix listing
the acronyms used in the book and moved some of the more advanced material on
pulse propagation into an appendix.
While we have mostly added new material, we have also removed some chapters
present in the first edition. We have eliminated the chapter on broadcast-and-select
networks, as these networks are mostly of academic interest today. Likewise, we
also removed the chapter describing optical networking testbeds as they are mostly
of historical importance at this point. Interested readers can obtain a copy of these
chapters on the Internet at www.mkp.com/opticalnet2.
Teaching and Learning from This Book
This book can be used as a textbook for graduate courses in electrical engineering
or computer science. Much of the material in this book has been covered in courses
taught by us. Chapters 2–5 cover components and transmission technology aspects of
Preface to the Second Edition xxxi
optical networking, and Chapters 6–13 deal with the networking aspects. To under-
stand the networking issues, students will require a basic undergraduate-level knowl-
edge of communication networks. We have tried to make the transmission-related
chapters of the book accessible to networking professionals. For example, compo-
nents are treated first in a simple qualitative manner from the viewpoint of a net-
work designer, but their principle of operation is then explained in detail. Some prior
knowledge of semiconductors and electromagnetics will be helpful in appreciating
the detailed treatment in some of the sections.
Readers wishing to obtain a broad understanding of the major aspects of optical
networking can read Chapters 1, 6, 7, and 13. Those interested in getting a basic
appreciation of the underlying components and transmission technologies can read
through Chapters 1–5, skipping the quantitative sections.
The book can be the basis for a graduate course in an electrical engineering or
computer science curriculum. A networks-oriented course might emphasize network
architectures and control and management, by focusing on Chapters 6–13, and skim
over the technology portions of the book. Likewise, a course on optical transmission
in an electrical engineering department might instead focus on Chapters 2–5 and
omit the remaining chapters. Each chapter is accompanied by a number of prob-
lems, and instructors may obtain a solution manual by contacting the publisher at
Acknowledgments
We were fortunate to have an outstanding set of reviewers who made a significant ef-
fort in reading through the chapters in detail and providing us with many suggestions
to improve the coverage and presentation of material. They have been invaluable in
shaping this edition. Specifically, we would like to thank Paul Green, Goff Hill, David
Hunter, Rao Lingampalli, Alan McGuire, Shawn O’Donnell, Walter Johnstone, Alan
Repech, George Stewart, Suresh Subramaniam, Eric Verillow, and Martin Zirngibl.
In addition, we would like to acknowledge Bijan Raahemi, Jim Refi, Krishna Thya-
garajan, and Mark R. Wilson who provided inputs and comments on specific topics
and pointed out some mistakes in the first edition. Mark R. Wilson was kind enough
to provide us with several applications-oriented problems from his class, which we
have included in this edition. We would also like to thank Amit Agarwal, Shyam
Iyer, Ashutosh Kulshreshtha, and Sarath Kumar for the use of their mesh network
design tool, Ashutosh Kulshreshtha for also computing the detailed mesh network
design example, Tapan Kumar Nayak for computing the lightpath topology design
example, Parthasarathi Palai for simulating the EDFA gain curves, and Rajeev Roy
for verifying some of our results. As always, we take responsibility for any errors
or omissions and would greatly appreciate hearing from you as you discover them.
Please email your comments to [email protected].
Preface to the Current
Edition
Optical networking has matured considerably since the publication of the last edition
of this book in 2002. A host of new technologies including reconfigurable optical
add/drop multiplexers and sophisticated modulation formats are now mainstream,
and there has been a significant shift in telecommunications networks migrating to
a packet-over-optical infrastructure. We have incorporated many of these into this
revised edition.
In Chapter 2, we expanded the discussion on multimode fiber and added sections
on photonic crystal and plastic fibers. Chapter 6 has been rewritten with new sections
on Generic Framing Procedure, Optical Transport Network, and Resilient Packet
Ring (RPR). The coverage of Synchronous Optical Networks (SONET) now includes
Virtual Concatenation (VCAT) and the Link Capacity Adjustment Scheme (LCAS).
There is also expanded coverage of Ethernet and Multiprotocol Label Switching
(MPLS) that includes the development of these technologies to support carrier grade
service. Chapter 7 is devoted to architectural considerations underlying Wavelength
Division Multiplexing (WDM) network elements, and we have updated the section
on Reconfigurable Optical Add Drop Multiplexers (ROADMs). Chapter 8 reflects
the changes in network management and control, including more discussion on
packet transport considerations. Chapter 9 includes network survivability of client
layer protocols such as Ethernet, MPLS, and RPR, which is important to understand
the role of optical networks in survivability.
As with the previous editions, this book is intended to for use by a broad au-
dience including students, engineers in optical component, equipment, and service
provider companies, network planners, investors, venture capitalists, and indus-
try and investment analysts. It can be used as a textbook for graduate courses in
xxxiii
xxxiv Preface to the Current Edition
electrical engineering or computer science. Please see the section “Teaching and
Learning from This Book" on page xxx for some guidance on this. Instructors can
obtain a solutions manual by contacting the publisher through the book’s web page,
www.elsevierdirect.com/9780123740922.
We would like to acknowledge the invaluable assistance provided by Karen Liu
in revising Chapter 2, especially the sections on multimode, photonic crystal and
plastic fibers. We would also like to thank Ori Gerstel for insightful discussions on
optical networks and Parthasarathi Palai for inputs on the DWDM network case
studies.