Optical Communications: Components and Systems

272 Pages·1995·10.463 MB·English

by  M. J. N. Sibley (auth.)

Optical Communications
Macmillan New Electronics Series
Series Editor: Paul A. Lynn
G. J. Awcock and R. Thomas, Applied Image Processing
Rodney F. W. Coates, Underwater Acoustic Systems
M. D. Edwards, Automatic Logic Synthesis Techniques for Digital Systems
P. J. Fish, Electronic Noise and Low Noise Design
W. Forsythe and R. M. Goodall, Digital Control
C. G. Guy, Data Communications for Engineers
Paul A. Lynn, Digital Signals, Processors and Noise
Paul A. Lynn, Radar Systems
R. C. V. Macario, Cellular Radio - Principles and Design
A. F. Murray and H. M. Reekie, Integrated Circuit Design
F. J. Owens, Signal Processing of Speech
Dennis N. Pim, Television and Teletext
M. Richharia, Satellite Communications Systems - Design Principles
M. J. N. Sibley, Optical Communications, second edition
P. M. Taylor, Robotic Control
G. S. Virk, Digital Computer Control Systems
Allan Waters, Active Filter Design
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Customer Services Department, Macmillan Distribution Ltd
Houndmills, Basingstoke, Hampshire, RG21 2XS, England.
Optical Communications
Components and Systems
M. J. N. Sibley
Division of Electronics and Communications
The University of Huddersfield
Second Edition
Macmillan New Electronics
Introductions to Advanced Topics
~
MACMILLAN
© M. J. N. Siblev 1990. 1995
All rights reserved. No reproduction, copy or transmission of
this publication may be made without written permission.
No paragraph of this publication may be reproduced, copied or
transmitted save with written permission or in accordance with
the provisions of the Copyright, Designs and Patents Act 1988,
or under the terms of any licence permitting limited copying
issued by the Copyright Licensing Agency, 90 Tottenham Court
Road, London W1P 9HE.
Any person who does any unauthorised act in relation to this
publication may be liable to criminal prosecution and civil
claims for damages.
First edition 1990
Second edition 1995
Published by
THE MACMILLAN PRESS LTD
Houndmills, Basingstoke, Hampshire RG21 2XS
and London
Companies and representatives
throughout the world
ISBN 978-0-333-61792-2 ISBN 978-1-349-13524-0 (eBook)
DOI 10.1007/978-1-349-13524-0
A catalogue record of this book is available
from the British Library
Contents
Series Editor's Foreword ix
Preface to First Edition x
Preface to Second Edition xii
List of Symbols xiii
1 Introduction 1
1.1 Historical background 1
1.2 The optical communications link 4
2 Optical Fibre 6
2.1 Propagation of light in a dielectric 7
2.1.1 The wave equation 8
2.1.2 Propagation parameters 9
2.1.3 Group velocity and material dispersion 14
2.2 Propagation in a planar dielectric waveguide 19
2.2.1 Reflection and refraction at boundaries 19
2.2.2 Propagation modes - ray-path analysis 26
2.2.3 Propagation modes - modal analysis 30
2.2.4 Modal dispersion - ray-path analysis 38
2.2.5 Modal dispersion - modal analysis 39
2.2.6 Waveguide dispersion- ray-path and modal analysis 41
2.2.7 Numerical aperture 43
2.3 Propagation in optical fibres 44
2.3.1 Propagation in step-index optical fibres 45
2.3.2 Dispersion in cylindrical waveguides 52
2.3.3 Step-index multimode fibre 54
2.3.4 Step-index single-mode fibre 58
2.3.5 Graded-index fibre 62
2.4 Calculation of fibre bandwidth 62
2.5 Attenuation in optical fibres 66
2.5.1 Impurity absorption 66
2.5.2 Rayleigh scattering 67
v
vi Contents
2.5.3 Material absorption 67
2.5.4 Electron absorption 68
2.5.5 PCS and all-plastic fibres 68
2.6 Fibre materials and fabrication methods 68
2.6.1 Materials 68
2.6.2 Modified chemical vapour deposition (MCVD) 69
2.6.3 Fibre drawing from a preform 71
2.6.4 Fibre drawing from a double crucible 72
2.7 Connectors and couplers 72
2.7.1 Optical fibre connectors 72
2.7.2 Optical fibre couplers 74
3 Optical Transmitters 76
3.1 Semiconductor diodes 76
3.1.1 Intrinsic semiconductor material 76
3.1.2 Extrinsic semiconductor material 80
3.1.3 The p-n junction diode under zero bias 83
3.1.4 The p-n junction diode under forward bias 89
3.2 Light emission in semiconductors 95
3.2.1 Direct and indirect band-gap materials 95
3.2.2 Rate equations 97
3.3 Heterojunction semiconductor light sources 103
3.4 Light emitting diodes (LEDs) 105
3.4.1 Surface emitting LEDs 106
3.4.2 Edge emitting LEDs (ELEDs) 107
3.4.3 Spectral characteristics 107
3.4.4 Modulation capabilities and conversion efficiency 108
3.5 Semiconductor laser diodes (SLDs) 110
3.5.1 Stimulated emission 112
3.5.2 Spectral characteristics 122
3.5.3 Modulation capabilities 126
3.5.4 SLD structures 132
3.5.5 Packaging and reliability 134
3.6 Solid-state and gas lasers 135
3.6.1 Nd3+: YA G lasers 136
3.6.2 HeNe lasers 138
3.7 Light-wave modulation 139
3.7.1 LED drive circuits 139
3.7.2 SLD drive circuits 141
3.7.3 External modulators 141
3.8 Fibre amplifiers and lasers 151
Contents vii
4 Photodiodes 153
4.1 Photoconduction in semiconductors 155
4.1.1 Photon absorption in intrinsic material 155
4.1.2 Photon absorption in reverse-biased p-n diodes 157
4.2 PIN photodiodes 163
4.2.1 Structure 164
4.2.2 Depletion layer depth and punch-through voltage 164
4.2.3 Speed limitations 165
4.2.4 Photodiode circuit model 168
4.2.5 Long-wavelength PIN photodiodes 169
4.3 Avalanche photodiodes (APDs) 170
4.3.1 APD structures 171
4.3.2 Current multiplication 172
4.3.3 Speed limitations 173
4.4 Photodiode noise 175
4.4.1 PIN photodiode noise 17 5
4.4.2 APD noise 177
5 Introduction to Receiver Design 182
5.1 Fundamentals of noise performance 183
5.2 Digital receiver noise 185
5 .2.1 Raised-cosine spectrum pulses 186
5.2.2 Determination of / and / 189
2 3
5.2.3 Statistical decision theory 191
5.2.4 Photodiode noise 197
5.2.5 Timing extraction 200
5.3 Analogue receiver noise 203
5.4 Comparison of APD and PIN receivers 205
5.5 Measurement and prediction of receiver sensitivity 207
5.5.1 Measurement of receiver sensitivity 207
5.5.2 Prediction of receiver sensitivity 208
6 Preamplifier Design 211
6.1 High input impedance preamplifiers 212
6.1.1 Frequency response 213
6.1.2 Noise analysis 215
6.1.3 Dynamic range 216
6.1.4 Design example 216
6.2 Transimpedance preamplifiers 218
6.2.1 Frequency response 220
6.2.2 Noise analysis 222
6.2.3 Dynamic range 223
6.2.4 Design example 223
viii Contents
6.3 Common-collector front-end transimpedance designs 225
6.3.1 Frequency response 226
6.3.2 Noise analysis 227
6.3.3 Design example 228
7 Current Systems and Future Trends 230
7.1 System design 230
7.2 Current systems 233
7.3 Future trends 235
7 .3.1 Fluoride-based optical fibres 235
7 .3.2 Optical solitons 236
7.3.3 Advanced semiconductor lasers 237
7.3.4 Mode-locking 239
7.3.5 Coherent detection systems 240
7 .3.6 Optical broadcasting 244
Bibliography and References 246
Index 250
Series Editor's Foreword
The rapid development of electronics and its engineering applications en
sures that new topics are always competing for a place in university and
college courses. But it is often difficult for lecturers to find suitable books
for recommendation to students, particularly when a topic is covered by a
short lecture module, or as an 'option'.
Macmillan New Electronics offers introductions to advanced topics. The
level is generally that of second and subsequent years of undergraduate
courses in electronic and electrical engineering, computer science and physics.
Some of the authors will paint with a broad brush; others will concentrate
on a narrower topic, and cover it in greater detail. But in all cases the
titles in the Series will provide a sound basis for further reading of the
specialist literature, and an up-to-date appreciation of practical applica
tions and likely trends.
The level, scope and approach of the Series should also appeal to prac
tising engineers and scientists encountering an area of electronics for the
first time, or needing a rapid and authoritative update.
Paul A. Lynn
ix