An Introduction to Photonic Switching Fabrics

536 Pages·1993·15.44 MB·English

by  H. Scott Hinton, J. R. Erickson, T. J. Cloonan, F. A. P. Tooley, F. B. McCormick, A. L. Lentine (auth.)

An Introduction to
Photonie Switching Fabrics
Applications of Communications Theory
Series Editor: R. W. Lucky, Bellcore
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An Introduction to
Photonic Switching Fabrics
H. Scott Hinton
McGill University
Montreal, Quebec, Canada
In collaboration with
J. R. Erickson
T. J. Cloonan
F. A. P. Tooley
F. B. McCormick
and
A. L. Lentine
Springer Science+Business Media, LLC
Llbrary of Congress Cataloglng-ln-Publleatlon Data
Hinten, H. Seett.
An Intreduetien te phetenie switchlng fabrlcs I H. Scett Hinten;
In cellaberatien wlth J.R. Ericksen ... [et al.l.
p. cm. -- (Appl icatiens ef cemmunicatiens theeryl
Inc 1u d es bl b li egraph i ca I references and 1 ndex.
1. Telecemmunicatlen--Swltching systems. 2. Phetenics.
3. Swltching circuits. I. Title. II. Series.
TKS103.8.HS6 1993
621.381S·37--dc20 93-22642
CIP
ISBN 978-1-4757-9173-0 ISBN 978-1-4757-9171-6 (eBook)
DOI 10.1007/978-1-4757-9171-6
C 1993 Springer Science+Business Media New York
Originally published by Plenum Press, New York in 1993.
Softcover reprint of the hardcover 1s t edition 1993
All rights reserved
No part of this book may be reproduced, stored in a retrievaJ system, or transmitted in any form or by any
means, e1ectronic, mechanicaJ, photocopying, microti1ming, recording, or otherwise, without written
permission from the Publisher
Preface
Over the past ten years there has been an increasing interest in developing
photonic switching fabrics as the predicted broadband services approach
reality. The result of this interest is that many different types of photonic
switching fabrics have been proposed and demonstrated. This book gives
an overview of these photonic switching fabrics from a system designer's
perspective.
The book is divided into six chapters. Chapter I provides an introduc-
tion to the different types of photonic switching fabrics and the technologies
used to implement them. lt inc1udes discussion of the future requirements
for the information age, strengths and limitations of photonic technology,
switching fabrics based on optically transparent devices, and switching fab-
rics based on logic devices. Chapter 2 provides an overview of optically
transparent devices and their attributes. It begins with a discussion of light
propagation in a dielectric media followed by a review of several modulators,
switching devices (e.g., directional couplers), linear optical amplifiers, and
spatial light modulators. Chapter 3, written by J. R. Erickson and H. S.
Hinton, outlines the proposed systems based on the previously discussed
optically transparent devices. It inc1udes discussion of space-division net-
works and several types of multiple-access networks inc1uding both time-
division multiple access and spectral-division multiple access. Chapter 4,
written by F. A. P. Tooley, A. L. Lentine, and H. S. Hinton, introduces
optical logic devices. It discusses intrinsic bistability and optical nonlineari-
ties, quantum-well optoelectronic devices (e.g., SEEDs), and active switching
transistor devices. Chapter 5, written by F. B. McCormick and H. S. Hinton,
provides an overview of the optical hardware required for switching fabrics
based on logic devices and free-space optical interconnection. This inc1udes
a review of imaging and aberrations in free-space systems, polarization, spot
v
vi Preface
array generation, and beam array combination. Finally, Chapter 6, written
by T. J. Cloonan and H. S. Hinton, discusses the systems that can be imple-
mented using logic devices. It inc1udes an overview of switching architec-
tures, a discussion of the architectural building blocks required in free-space
switching systems, and an overview of free-space photonic switching system
architectures.
I am grateful to many people for their help in putting this book together,
especially my coauthors J. R. Erickson, T. J. Cloonan, F. B. McCormick,
F. A. P. Tooley, and A. L. Lentine. Finally, I would like to thank my wife,
Sharon, for providing continuous encouragement and support.
Contents
Chapter 1. Introduction
1.1. Switching Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I
1.2. The Strengths and Limitations of the Photonie Technology ........ 4
1.2.1. Temporal Bandwidth .................................. 4
1.2.2. Communication Energy and Power ...................... 7
1.2.3. Skew ................................................ \3
1.2.4. Spatial Bandwidth .................................... 14
1.2.5. Secondary Strengths .................................. 15
1.2.6. New Architectures .................................... 15
1.3. Switching Fabrics Based on Relational Devices .................. 16
1.3.1. Switching Fabrics Using Space Channe\s . . . . . . . . . . . . . . . . . . 16
1.3.1.1. Fabrics Based on Directional Couplers .......... 16
1.3.1.2. Fabrics Based on Optical Amplifiers ............ 18
1.3.1.3. Fabrics Based on Spatial Light Modulators ...... 19
1.3.2. Switching Fabrics Using Time Channe\s .................. 20
1.3.2.1. Active Reconfigurable Fabrics .................. 20
1.3.2.2. Passive Shared Media Fabrics .................. 22
1.3.3. Switching Fabrics Using Wave\ength Channe\s ............ 25
1.3.3.1. Wavelength Interchanger ...................... 25
1.3.3.2. Passive Shared Media Fabrics .................. 26
1.3.4. Multidivisional Fabrics ................................ 27
1.4. Switching Fabrics Based on Logic Devices ...................... 29
1.4.1. Switching Nodes ...................................... 30
1.4.2. Three-Dimensional Interconnection Networks ............ 31
1.4.3. Networks Using Electronic Nodes. . . . . . . . . . . . . . . . . . . . . . . . 32
1.5. Summary .................................................. 33
1.6. Exercises.................................................... 34
References .................................................. 35
vii
viii Contents
Chapter 2. Optically Transparent Devices
2.1. Introduction ................................................ 39
2.2. Light Propagating in a DieJectric Medium ...................... 39
2.2.1. Index Ellipsoid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2.2.2. Linear Electro-optic Effect (PockeJs Effect) . . . . . . . . . . . . . . . . 43
2.3. Modulators.................................................. 45
2.3.1. Electro-optic Phase Modulators. . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.3.2. Y-Branch Intensity Modulator .......................... 47
2.4. Photonie Switching Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.4.1. Directional Couplers .................................. 47
2.4.1.1. Coupling between Waveguides .................. 48
2.4.1.2. Cross State Design ............................ 51
2.4.1.3. Bar State Design .............................. 53
2.4.1.4. Bends in Waveguides .......................... 55
2.4.1.5. Polarization.................................. 56
2.4.1.6. Current System Design Constraints .............. 58
2.4.2. Balanced-Bridge Switch ................................ 60
2.4.3. X-Switches............................................ 61
2.4.4. Digital Electro-optic Switches .......................... 63
2.5. Linear Optical Amplifiers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
2.5.1. Material Gain ........................................ 66
2.5.2. Traveling Wave Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
2.5.3. Fabry-Perot Amplifiers ................................ 69
2.5.4. Near Traveling Wave Amplifiers ........................ 72
2.5.5. Backward Gain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
2.5.6. Systems Considerations ................................ 75
2.6. Spatial Light Modulators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
2.7. Problems.................................................... 77
References .................................................. 79
Chapter 3. Optically Transparent Systems
3.1. Introduction ................................................ 83
3.2. Space-Division Switching Networks ............................ 83
3.2.1. Switching Network Characterization .................... 84
3.2.2. Partially Connected Networks .......................... 85
3.2.3. Fully Connected Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
3.2.4. Rearrangeably Nonblocking Networks. . . . . . . . . . . . . . . . . . . . 87
3.2.5. Wide-Sense Nonblocking Networks ...................... 90
3.2.6. Strictly Nonblocking Networks . . . . . . . . . . . . . . . . . . . . . . . . . . 91
3.2.7. Redundancy in Networks .............................. 94
3.2.8. Blocking Probability .................................. 95
3.2.9. Output Concurrency .................................. 95
3.3. Space-Division Switching with Optically Transparent Devices ...... 96
3.3.1. Optically Transparent Systems Using Spatial Light
Modulators .......................................... 97
Contents ix
3.3.2. Optically Transparent Systems Using Guided-Wave Electro-
optic Switches ........................................ 99
3.3.2.1. Crossbar Architecture Using Directional Coupler
Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
3.3.2.2. Router/Selector Architecture Using Directional
Coupler Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
3.3.2.3. Benes Architecture Using Directional Coupler
Switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
3.3.2.4. Coupler Count, Loss, and Cross Talk Comparisons 110
3.3.2.5. Architecting around Cross Talk Limitations ...... 112
3.3.2.6. Other Optically Transparent System Design
Parameters .................................. 112
3.4. Multiple-Access Channel .............. . . . . . . . . . . . . . . . . . . . . . . . . 113
3.5. Time-Division Multiple Access Networks . . . . . . . . . . . . . . . . . . . . . . . . 114
3.5.1. Bit- versus Block-Multiplexing .......................... 114
3.5.2. Bit- and Block-Switching Using Optically Transparent
Devices .............................................. 116
3.5.3. CDMA Switching .................................... 119
3.5.4. Combined Time- and Space-Division Switching . . . . . . . . . . . . 121
3.5.5. Packet Switching ...................................... 124
3.6. Spectral-Division Multiple Access Networks .................... 124
3.6.1. Electrical Frequency-Division Multiple Access ............ 125
3.6.2. Subcarrier Multiple Access Systems. . . . . . . . . . . . . . . . . . . . . . 125
3.6.3. Optical Multiple Access Networks ...................... 128
3.6.3.1. Optical FDMA FSK Direct Detection Example. . . . 135
3.6.3.2. Optical FDMA FSK Coherent Detection Example 140
3.6.3.3. Wavelength-Division Multiple Access Network
Example .................................... 142
3.6.4. Multihop Lightwave Networks .......................... 145
3.6.5. Combined WDMA and Subcarrier Multiplexed Systems.... 148
3.6.6. Wavelength Routing .................................. 149
3.7. Problems.................................................... 149
3.8. Solutions to Problems ........................................ 153
References .................................................. 158
Chapter 4. Optical Logic Devices
4.1. Introduction ................................................ 163
4.2. Optical Nonlinearities ........................................ 166
4.2.1. Introduction.......................................... 166
4.2.2. Nonresonant Optical Nonlinearities . . . . . . . . . . . . . . . . . . . . . . 167
4.2.3. Resonant Optical Nonlinearities ........................ 169
4.2.3.1. Dynamic Moss-Burstein Shift (InSb) ............ 172
4.2.3.2. Exciton Saturation Nonlinearity (Bulk GaAs) .... 173
4.2.4. Introduction to Electroabsorption and SEEDs ............ 174