A GUIDE TO THE FUNDAMENTAL THEORY AND PRACTICE OF OPTICAL COMMUNICATION

FiberOptic and Atmospheric Optical Communicationoffers a much needed guide to characterizing and overcoming the drawbacks associated with optical communication links that suffer from various types of fading when optical signals with information traverse these wireless (atmospheric) or wired (fiber optic) channels.

The authorsnoted experts on the topicpresent material that aids in predicting the capacity, data rate, spectral efficiency, and bit-error-rate associated with a channel that experiences fading. They review modulation techniques and methods of coding and decoding that are useful when implementing communications systems. The book also discusses how to model the channels, including treating distortion due to the various fading phenomena. Light waves and their similarity to radio waves are explored, and the way light propagates through the atmosphere, through materials, and through the boundary between two materials is explained. This important book:

Written for professionals dealing with optical and electro-optical communications,Fiber Optic and Atmospheric Optical Communicationexplores the theory and practice of optical communication both when the optical signal is propagating through the atmosphere and when it is propagating through an optical fiber.

NATHAN BLAUNSTEIN is Professor Emeritus in the Department of Communication System Engineering at Ben Gurion University of the Negev.??

SHLOMO ENGELBERG is a Professor at the Jerusalem College of Technology and is the Dean of its School of Engineering and Computer Science.

EVGENII KROUK is Professor at the Tikhonov Moscow Institute of Electronics and Mathematics at the National Research University Higher School of Economics, Russia.

MIKHAIL SERGEEV is Professor in the Department of Computer Systems and Networks at the St. Petersburg State University of Airspace Instrumentation, Russia.

Preface xi

Acknowledgments xv

Abbreviations xvii

Nomenclature xix

Part I Optical Communication Link Fundamentals1

1 Basic Elements of Optical Communication3

1.1 Spectrum of Optical Waves 3

1.2 Optical Communication in Historical Perspective 4

1.3 Optical Communication Link Presentation 5

References 8

2 Optical Wave Propagation11

2.1 Similarity of Optical and Radio Waves 11

2.2 Electromagnetic Aspects of Optical Wave Propagation 13

2.3 Propagation of Optical Waves in Free Space 16

2.4 Propagation of Optical Waves Through the Boundary of Two Media 16

2.4.1 Boundary Conditions 16

2.4.2 Main Formulations of Reflection and Refraction Coefficients 17

2.5 Total Intrinsic Reflection in Optics 20

2.6 Propagation of Optical Waves in Material Media 23

2.6.1 Imperfect Dielectric Medium 25

2.6.2 Good Conductor Medium 25

Problems 25

References 28

Part II Fundamentals of Optical Communication29

3 Types of Signals in Optical Communication Channels31

3.1 Types of Optical Signals 31

3.1.1 Narrowband Optical Signals 31

3.1.2 Wideband Optical Signals 34

3.2 Mathematical Description of Narrowband Signals 35

3.3 Mathematical Description of Wideband Signals 39

References 41

4 An Introduction to the Principles of Coding and Decoding of Discrete Signals43

4.1 Basic Concepts of Coding and Decoding 43

4.1.1 General Communication Scheme 43

4.1.2 The Binary Symmetric Channel (BSC) 45

4.1.3 Channel Model with AWGN 46

4.2 Basic Aspects of Coding and Decoding 47

4.2.1 Criteria of Coding 47

4.2.2 Code Parameters for Error Correction 50

4.2.3 Linear Codes 51

4.2.4 Estimation of Error Probability of Decoding 54

4.3 Codes with Algebraic Decoding 56

4.3.1 Cyclic Codes 56

4.3.2 BCH Codes 57

4.3.3 ReedSolomon Codes 59

4.4 Decoding of Cyclic Codes 60

References 63

5 Coding in Optical Communication Channels67

5.1 Peculiarities of Cyclic Codes in Communication Systems 67

5.2 Codes with Low Density of Parity Checks 68

5.2.1 Basic Definitions 68

5.2.2 Decoding of LDPC Codes 72

5.2.3 Construction of Irregular LDPC Codes 73

5.2.4 Construction of Regular LDPC Codes 74

5.3 Methods of Combining Codes 76

5.4 Coding in Optical Channels 79

References 83

6 Fading in Optical Communication Channels87

6.1 Parameters of Fading in Optical Communication Channel 87

6.1.1 Time Dispersion Parameters 88

6.1.2 Coherence Bandwidth 89

6.1.3 Doppler Spread and Coherence Time 89

6.2 Types of Small-Scale Fading 91

6.3 Mathematical Description of Fast Fading 93

6.3.1 Rayleigh PDF and CDF 94

6.3.2 Ricean PDF and CDF 96

6.3.2.1 Gamma-Gamma Distribution 99

6.4 Mathematical Description of Large-Scale Fading 100

6.4.1 Gaussian PDF and CDF 101

References 102

7 Modulation of Signals in Optical Communication Links103

7.1 Analog Modulation 104

7.1.1 Analog Amplitude Modulation 104

7.1.2 Analog Angle Modulation Frequency and Phase 106

7.1.2.1 Phase Modulation 107

7.1.3 Spectra and Bandwidth of FM or PM Signals 107

7.1.4 Relations Between SNR and Bandwidth in AM and FM Signals 108

7.2 Digital Signal Modulation 109

7.2.1 Main Characteristics of Digital Modulation 110

7.2.1.1 Power Efficiency and Bandwidth Efficiency 110

7.2.1.2 Bandwidth and Power Spectral Density of Digital Signals 111

7.2.2 Linear Digital Modulation 112

7.2.2.1 Amplitude Shift Keying (ASK) Modulation 112

7.2.2.2 Binary Phase Shift Keying (BPSK) Modulation 113

7.2.2.3 Quadrature Phase Shift Keying (QPSK) Modulation 114

7.2.3 Nonlinear Digital Modulation 114

7.2.3.1 Frequency Shift Keying (FSK) Modulation 114

Problems 115

References 115

8 Optical Sources and Detectors117

8.1 Emission and Absorption of Optical Waves 117

8.2 Operational Characteristics of Laser 119

8.3 Light-Emitting Sources and Detectors 122

8.3.1 Light-Emitting pn Type Diode 122

8.3.2 Laser pn Type Diode 124

8.3.3 Photodiode 125

8.3.4 PiN and pn Photodiodes Principle of Operation 126

8.4 Operational Characteristics of Light Diodes 129

References 130

Part III Wired Optical Communication Links133

9 Light Waves in Fiber Optic Guiding Structures135

9.1 Propagation of Light in Fiber Optic Structures 135

9.1.1 Types of Optical Fibers 135

9.1.2 Propagation of Optical Wave Inside the Fiber Optic Structure 137

References 139

10 Dispersion Properties of Fiber Optic Structures141

10.1 Characteristic Parameters of Fiber Optic Structures 141

10.2 Dispersion of Optical Signal in Fiber Optic Structures 142

10.2.1 Material Dispersion 142

10.2.2 Modal Dispersion 143

Problems 145

References 146

Part IV Wireless Optical Channels147

11 Atmospheric Communication Channels149

11.1 Basic Characteristics of Atmospheric Channel 149

11.2 Effects of Aerosols on Atmospheric Communication Links 150

11.2.1 Aerosol Dimensions 150

11.2.2 Aerosol Altitudes Localization 151

11.2.3 Aerosol Concentration 152

11.2.4 Aerosol Size Distribution and Spectral Extinction 152

11.3 Effects of Hydrometeors 154

11.3.1 Effects of Fog 154

11.3.2 Effects of Rain 155

11.3.3 Effects of Clouds 157

11.3.3.1 Snow 158

11.4 Effects of Turbulent Gaseous Structures on Optical Waves Propagation 158

11.4.1 Turbulence Phenomenon 158

11.4.2 Scintillation Phenomenon of Optical Wave Passing the Turbulent Atmosphere 161

11.4.3 Scintillation Index 162

11.4.4 Signal Intensity Scintillations in the Turbulent Atmosphere 162

11.4.5 Effects of Atmosphere Turbulences on Signal Fading 165

11.5 Optical Waves Propagation Caused by Atmospheric Scattering 166

References 168

Part V Data Stream Parameters in Atmospheric and Fiber Optic Communication Links with Fading173

12 Transmission of Information Data in Optical Channels: Atmospheric and Fiber Optics175

12.1 Characteristics of Information Signal Data in Optical Communication Links 176

12.2 Bit Error Rate in Optical Communication Channel 181

12.3 Relations Between Signal Data Parameters and Fading Parameters in Atmospheric Links 183

12.4 Effects of Fading in Fiber Optic Communication Link 188

References 191

Index 195