Table Of ContentEngineering – Electrical Bi nh
S e c o n d E d i t i o n
Second Edition
Advanced Digital Optical Communications
Advanced Digital
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“This book is excellent and potentially can be used by many universities. … I have
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not seen that any books are better than this book in this topic.”
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—John Xiupu Zhang, Concordia University, Montreal, Quebec, Canada
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This second edition of Digital Optical Communications provides a compre- e
Optical Communications
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hensive treatment of the modern aspects of coherent homodyne and self-co-
herent reception techniques using algorithms incorporated in digital signal D
processing (DSP) systems and DSP-based transmitters to overcome several i
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linear and nonlinear transmission impairments and frequency mismatches
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between the local oscillator and the carrier, as well as clock recovery and
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cycle slips. These modern transmission systems have emerged as the core l
technology for Tera-bits per second (bps) and Peta-bps optical Internet for O
the near future. p
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Featuring extensive updates to all existing chapters, Advanced Digital
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Optical Communications, Second Edition:
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• Contains new chapters on optical fiber structures and propagation,
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optical coherent receivers, DSP equalizer algorithms, and high-order m
spectral DSP receivers
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• Examines theoretical foundations, practical case studies,
and MATLAB® and Simulink® models for simulation transmissions u
• Includes new end-of-chapter practice problems and useful appendices to n
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supplement technical information c
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Downloadable content available with qualifying course adoption t
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Advanced Digital Optical Communications, Second Edition supplies a
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fundamental understanding of digital communication applications in optical
communication technologies, emphasizing operation principles versus heavy
mathematical analysis. It is an ideal text for aspiring engineers and a valuable
professional reference for those involved in optics, telecommunications, Le Nguyen Binh
electronics, photonics, and digital signal processing.
S e c o n d
K22489 E d i t i o n
ISBN: 978-1-4822-2652-2
90000
9 781482 226522
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Second Edition
Advanced Digital
Optical Communications
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Optics and Photonics
Series Editor
Le Nguyen Binh
Huawei Technologies, European Research Center, Munich, Germany
1. Digital Optical Communications, Le Nguyen Binh
2. Optical Fiber Communications Systems: Theory and Practice with MATLAB®
and Simulink® Models, Le Nguyen Binh
3. Ultra-Fast Fiber Lasers: Principles and Applications with MATLAB® Models,
Le Nguyen Binh and Nam Quoc Ngo
4. Thin-Film Organic Photonics: Molecular Layer Deposition and Applications,
Tetsuzo Yoshimura
5. Guided Wave Photonics: Fundamentals and Applications with MATLAB®,
Le Nguyen Binh
6. Nonlinear Optical Systems: Principles, Phenomena, and Advanced Signal
Processing, Le Nguyen Binh and Dang Van Liet
7. Wireless and Guided Wave Electromagnetics: Fundamentals and
Applications, Le Nguyen Binh
8. Guided Wave Optics and Photonic Devices, Shyamal Bhadra and Ajoy Ghatak
9. Digital Processing: Optical Transmission and Coherent Receiving Techniques,
Le Nguyen Binh
10. Photopolymers: Photoresist Materials, Processes, and Applications,
Kenichiro Nakamura
11. Optical Fiber Communication Systems with MATLAB® and Simulink® Models,
Second Edition, Le Nguyen Binh
12. Advanced Digital Optical Communications, Second Edition, Le Nguyen Binh
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Second Edition
Advanced Digital
Optical Communications
Le Nguyen Binh
EUROPEAN RESEARCH CENTER,
HUAWEI TECHNOLOGIES, MUNICH, GERMANY
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MATLAB® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks does not warrant the
accuracy of the text or exercises in this book. This book’s use or discussion of MATLAB® software or related products
does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or particular
use of the MATLAB® software.
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© 2015 by Taylor & Francis Group, LLC
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Version Date: 20141219
International Standard Book Number-13: 978-1-4822-2653-9 (eBook - PDF)
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To my parents
To my wife, Phuong, and my son, Lam.
.
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Contents
Preface..........................................................................................................................................xxiii
Acknowledgments ..........................................................................................................................xxv
Author ..........................................................................................................................................xxvii
Acronyms ......................................................................................................................................xxix
Chapter 1 Introduction ..................................................................................................................1
1.1 Digital Optical Communications and Transmission Systems:
Challenging Issues .............................................................................................1
1.2 Enabling Technologies.......................................................................................3
1.2.1 Modulation Formats and Optical Signal Generation ...........................3
1.2.1.1 Binary Level .........................................................................3
1.2.1.2 Binary and Multilevel ...........................................................5
1.2.1.3 In-Phase and Quadrature-Phase Channels ...........................6
1.2.1.4 External Optical Modulation ................................................7
1.2.2 Advanced Modulation Formats ............................................................8
1.2.3 Incoherent Optical Receivers ...............................................................9
1.2.4 DSP-Coherent Optical Receivers .......................................................10
1.2.5 Transmission of Ultra-Short Pulse Sequence .....................................10
1.2.6 Electronic Equalization ......................................................................10
1.2.6.1 Feed-Forward Equalizer .....................................................11
1.2.6.2 Decision Feedback Equalization ........................................12
1.2.6.3 Minimum Mean Square Error Equalization.......................12
1.2.6.4 Placement of Equalizers .....................................................12
1.2.6.5 MLSE Electronic Equalizers ..............................................12
1.2.7 Ultra-Short Pulse Transmission .........................................................12
1.3 Organization of the Book Chapters .................................................................13
References ..................................................................................................................17
Chapter 2 Optical Fibers .............................................................................................................21
2.1 Overview .........................................................................................................21
2.2 Optical Fiber: General Properties ...................................................................22
2.2.1 Geometrical Structures and Index Profile ..........................................22
2.2.2 Fundamental Mode of Weakly Guiding Fibers ..................................24
2.2.2.1 Solutions of the Wave Equation for Step-Index Fiber ........25
2.2.2.2 Single-Mode and Few-Mode Conditions ............................26
2.2.2.3 Gaussian Approximation: Fundamental Mode Revisited ......28
2.2.2.4 Cutoff Properties ................................................................33
2.2.2.5 Power Distribution ..............................................................33
2.2.2.6 Approximation of Spot Size r of Step-Index Fiber ...........34
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2.2.3 Equivalent Step-Index Description ....................................................35
2.3 Nonlinear Effects.............................................................................................35
2.3.1 Nonlinear Self-Phase Modulation Effects ..........................................36
2.3.2 Self-Phase Modulation .......................................................................36
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viii Contents
2.3.3 Cross-Phase Modulation.....................................................................37
2.3.4 Stimulated Scattering Effects .............................................................38
2.3.4.1 Stimulated Brillouin Scattering ..........................................38
2.3.4.2 Stimulated Raman Scattering .............................................39
2.3.4.3 Four-Wave Mixing Effects ..................................................40
2.4 Signal Attenuation in Optical Fibers ...............................................................41
2.4.1 Intrinsic or Material Absorption Losses ............................................41
2.4.2 Waveguide Losses ..............................................................................42
2.4.3 Attenuation Coefficient ......................................................................43
2.5 Signal Distortion through Optical Fibers ........................................................44
2.5.1 Material Dispersion ............................................................................45
2.5.2 Waveguide Dispersion ........................................................................48
2.5.2.1 Alternative Expression for Waveguide Dispersion
Parameter ............................................................................50
2.5.2.2 Higher-Order Dispersion ....................................................51
2.5.3 Polarization-Mode Dispersion ............................................................51
2.6 Transfer Function of Single-Mode Fibers .......................................................53
2.6.1 Linear Transfer Function ....................................................................53
2.6.2 Nonlinear Fiber Transfer Function .....................................................59
2.6.3 Transmission Bit Rate and the Dispersion Factor ..............................62
2.7 Fiber Nonlinearity Revisited ...........................................................................64
2.7.1 SPM and XPM Effects .......................................................................64
2.7.2 SPM and Modulation Instability ........................................................65
2.7.3 Effects of Mode Hopping ...................................................................66
2.7.4 SPM and Intrachannel Nonlinear Effects ..........................................66
2.7.5 Nonlinear Phase Noises in Cascaded Multispan Optical Link ..........70
2.8 Special Dispersion Optical Fibers ...................................................................71
2.9 SMF Transfer Function: Simplified Linear and Nonlinear
Operating Region ...........................................................................................72
2.10 Numerical Solution: Split-Step Fourier Method ..............................................77
2.10.1 Symmetrical SSFM ............................................................................77
2.10.1.1 Modeling of PMD ...............................................................78
2.10.1.2 Optimization of Symmetrical SSFM ..................................79
2.11 Concluding Remarks .......................................................................................80
References ..................................................................................................................80
Chapter 3 Optical Transmitters ...................................................................................................83
3.1 Optical Modulators ..........................................................................................83
3.1.1 Phase Modulators ...............................................................................84
3.1.2 Intensity Modulators ..........................................................................84
3.1.2.1 Phasor Representation and Transfer Characteristics ..........85
3.1.2.2 Chirp-Free Optical Modulators ..........................................86
3.1.3 Structures of Photonic Modulators ....................................................88
3.1.4 Operating Parameters of Optical Modulators ...................................89
3.2 Return-to-Zero Optical Pulses ........................................................................89
3.2.1 Generation ..........................................................................................89
3.2.2 Phasor Representation ........................................................................90
3.2.2.1 Phasor Representation of CSRZ Pulses ..............................91
3.2.2.2 Phasor Representation of RZ33 Pulses ...............................93
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