The Physical Fundamentals of Electro-Optics

286 Pages·2022·16.42 MB·English

by  Irit Juwiler, Nathan Blaunstein

The Physical
Fundamentals of
Electro-Optics

The Physical
Fundamentals of
Electro-Optics
By
Irit Juwiler and Nathan Blaunstein
The Physical Fundamentals of Electro-Optics

By Irit Juwiler and Nathan Blaunstein

This book first published 2022

Cambridge Scholars Publishing

Lady Stephenson Library, Newcastle upon Tyne, NE6 2PA, UK

British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library

Copyright © 2022 by Irit Juwiler and Nathan Blaunstein

All rights for this book reserved. No part of this book may be reproduced,
stored in a retrieval system, or transmitted, in any form or by any means,
electronic, mechanical, photocopying, recording or otherwise, without
the prior permission of the copyright owner.

ISBN (10): 1-5275-8476-3
ISBN (13): 978-1-5275-8476-1
CONTENTS

Preface ....................................................................................................... ix

List of Abbreviations ............................................................................... xiv

Chapter 1 .................................................................................................... 1
Fundamental Aspects of Electro-Optics
1.1 Spectrum of Optical Waves ............................................................ 2
1.2. Fiber Optic Links ........................................................................... 3
1.3. Main Elements and Devices in Electro-Optics .............................. 4
1.4. Noise in Optical Emitters and Detectors ........................................ 6
1.5. Presentation of Signals in Electro-Optics ...................................... 6
1.6. Types of Modulation of Optical Signals ........................................ 7
1.7. Wired (Fiber Optic) Fundamentals ................................................ 9
Bibliography ....................................................................................... 10

Chapter 2 .................................................................................................. 11
Electromagnetic Nature of Light
2.1. Optical Wave Electromagnetic Fundamentals ............................. 11
2.2. Propagation of Optical Waves in Free Space ............................... 14
2.3. Propagation of Optical Waves through the Boundary of Two
Media ............................................................................................ 16
2.3.1 Boundary conditions............................................................. 16
2.3.2 Main formulations of reflection and refraction coefficients ... 17
2.4. Total Intrinsic Reflection in Optics .............................................. 20
2.5. Propagation of Optical Waves in Materials ................................. 24
Exercises ............................................................................................. 27
Bibliography ....................................................................................... 33

Chapter 3 .................................................................................................. 34
Corpuscular Nature of Light
3.1. Elements of Quantum Theory ...................................................... 34
3.2. Structure of the Atom ................................................................... 39
3.2.1 Wave – Corpuscular Dualism ............................................... 39
3.2.2 Bohr’s Corpuscular Model of any Atom ............................. 43
3.2.3 De Brogli’s Wave – Corpuscular Dualism Concept ............. 49
vi Contents

3.2.4 Structure of Crystal Materials .............................................. 51
3.3. Semiconductor Fundamentals ...................................................... 54
3.3.1. Zonal Structure of Semiconductors ..................................... 55
3.3.2 Electrons and Holes .............................................................. 56
3.3.3 Joint Energy-Momentum Domain of Semiconductors ......... 58
3.3.4 P-type and N-type Semiconductors ...................................... 61
3.3.5 P-N Junction in Equilibrium ................................................. 62
Exercises ............................................................................................. 65
Bibliography ....................................................................................... 73

Chapter 4 .................................................................................................. 74
Basic Principles of Photonics and Laser Operation
4.1. Boltzmann Distribution ................................................................ 74
4.2. Fermi-Dirac Energy Distribution ................................................. 75
4.3. Interaction of Photons with Atoms .............................................. 77
4.3.1 Thermal Emission – Spontaneous, Stimulated,
and Absorption of Photons ...................................................... 77
4.3.2 Thermal Equilibrium between Atoms and Photons .............. 82
4.4. Electron and Hole Concentration in Semiconducting Materials .. 85
4.5. Law of Mass Action ..................................................................... 92
4.6. Generation and Recombination of Electrons and Holes
in Thermal Equilibrium ................................................................. 93
4.7. Photon Interactions with Semiconducting Materials.................... 98
4.7.1 Processes of Emission and Absorption of Light
in Semiconductor Materials ..................................................... 98
4.8. Physical Principles of Laser Operation ...................................... 102
Bibliography ..................................................................................... 107

Chapter 5 ................................................................................................ 109
Fundamentals of Light Emitters, Optical Diodes and Detectors
5.1. P-N Junction Operation Mode in Semiconductor Devices ........ 109
5.2. Laser Diodes .............................................................................. 117
5.2.1 Light-Emitted Diode (LED) ............................................... 117
5.2.2 Laser Diode (LD) ............................................................... 121
5.3. Photodiodes ................................................................................ 124
5.3.1 The p-n Photodiode ............................................................ 124
5.3.2 The p-i-n Photodiode .......................................................... 128
5.4. Multiplication of Photons – Avalanche Diodes ......................... 132
5.4.1 Multiplication of Photons ................................................... 132
5.4.2. Avalanche Photodiodes ..................................................... 135
5.5. Operational Characteristics of Light Photodiodes ..................... 141
The Physical Fundamentals of Electro-Optics vii
Exercises ........................................................................................... 144
Problems ........................................................................................... 151
Bibliography ..................................................................................... 153

Chapter 6 ................................................................................................ 154
Noise in Light Emitters and Diodes
6.1. Noise in Photodiodes and Light Emitters ................................... 154
6.2. Noise in Optical Receivers ......................................................... 162
Bibliography ..................................................................................... 165

Chapter 7 ................................................................................................ 166
Optical Amplifiers
7.1. Principles of Optical Amplification ........................................... 166
7.2. Amplification with Small Signal Gain ....................................... 167
7.3. Pumping Mechanism in Optical Amplifiers .............................. 169
7.4. Noise in Optical Amplifiers ....................................................... 174
7.5. Erbium Doped Fiber Amplifier (EDFA) .................................... 180
7.5.1. Structure and Principle of Operation of EDFA ................. 180
7.5.2 Gain Characteristics of EDFA ............................................ 182
7.5.3 Noise Characteristics of EDFA .......................................... 183
Exercises ........................................................................................... 184
Bibliography ..................................................................................... 189

Chapter 8 ................................................................................................ 190
Types of Signals in Optics
8.1. Narrowband or Continuous Wave Optical Signals .................... 190
8.2. Wideband or Impulse Optical Signals ........................................ 193
Bibliography ..................................................................................... 195

Chapter 9 ................................................................................................ 197
Modulation of Signals in Optics
9.1. Analog Modulation of Optical Signals ...................................... 198
9.1.1 Analog Amplitude Modulation ........................................... 198
9.1.2 Analog Frequency and Phase Modulation .......................... 200
9.1.3 Spectrum and Bandwidth of FM or PM Signals ................. 203
9.1.4 Relations between SNR and Bandwidth of AM and FM
Signals ................................................................................... 204
9.2. Digital Signal Modulation .......................................................... 205
9.2.1 Types of Linear Digital Modulation Techniques ................ 206
9.2.2 Nonlinear Digital Modulation ............................................ 209
Exercises ........................................................................................... 210
Bibliography ..................................................................................... 212
viii Contents

Chapter 10 .............................................................................................. 213
Optical Waves Propagation in Fiberoptic Structures
10.1. Types of Optical Fibers ............................................................ 213
10.2. Main Operational Parameters of Optical Fibers ....................... 215
10.3. Propagation of Optical Rays in a 2-D Plane Dielectric Guiding
Structure ...................................................................................... 216
10.4. Propagation of Optical Wave along the 3-D Fiber Optic
Structure ...................................................................................... 222
10.5. Dispersion of Signals in Fiber Optic Links .............................. 232
10.6. Attenuation and Scattering inside Fiber Optic Structures ........ 240
Summary ........................................................................................... 241
Exercises ........................................................................................... 242
Bibliography ..................................................................................... 258

Index ....................................................................................................... 259
PREFACE

This book is intended to appeal to any practicing optical scientist
and optical engineer who is concerned with the design, operation, and
service of wired (fiberoptic) and wireless optical systems for resolving both
the direct and the inverse problems of optical communication and optical
location, namely of LIDAR. It will be very useful for students of all three
degree levels, B.Sc., M.Sc., and Ph.D., who are concerned with the
performance of mathematical algorithms, theoretical and applied models, as
well as with the design, construction, and servicing of different optical
devices: from various kinds of laser, photodetectors, light emitters and
diodes, and optical amplifiers, wired waveguide optical structures, such as
fiberoptic structures – 2D and 3D – with applications in wireless (atmospheric)
networks, to LIDAR applications.
It should be mentioned that during the last 20–30 years a lot of
optical elements, devices, and systems have been developed and constructed
to satisfy the continually increasing demands of modern optical engineering
and photonics for wired and wireless communications and LIDAR
applications, including wide spectra – visual, infrared (IR) ultraviolet (UV)
– sensors, devices, and systems. And, if for wireless (atmospheric)
communication systems numerous excellent monographs have been
published (see bibliography in Refs. [1-4]), the role of fiberoptic
communication has been weakly illuminated. Moreover, the foundational
books regarding photonics, physical aspects of laser and optical detectors
operation, and photodiodes were published twenty to thirty years ago and
paid attention only to some specific fields of wide spectra optical physics
applications [5–8], accounting mostly either for a wide description of solid
materials, such as dielectrics and semiconductors and their role in different
optical sources and detectors operation, or fiberoptic communication,
ignoring basic aspects of such elements as optical emitters (lasers) and
detectors. During recent decades, many articles about all of these aspects
have been published, including articles by the authors of this book, but
general views on the problems of fiberoptic communication and lasers and
detectors as basic terminals of any wireless and wired optical
communication system or network were absent. Moreover, even such books
and papers that were recently published mostly paid attention to aspects of