This second edition of Digital Optical Communications provides a comprehensive treatment of the modern aspects of coherent homodyne and self-coherent reception techniques using algorithms incorporated in digital signal processing (DSP) systems and DSP-based transmitters to overcome several linear and nonlinear transmission impairments and frequency mismatching between the local oscillator and the carrier, as well as clock recovery and cycle slips. These modern transmission systems have emerged as the core technology for Tera-bits per second (bps) and Peta-bps optical Internet for the near future.
Featuring extensive updates to all existing chapters, Advanced Digital Optical Communications, Second Edition:
- Contains new chapters on optical fiber structures and propagation, optical coherent receivers, DSP equalizer algorithms, and high-order spectral DSP receivers
- Examines theoretical foundations, practical case studies, and MATLAB® and Simulink® models for simulation transmissions
- Includes new end-of-chapter practice problems and useful appendices to supplement technical information
Downloadable content available with qualifying course adoption
Advanced Digital Optical Communications, Second Edition supplies a 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, electronics, photonics, and digital signal processing.
Preface
Acknowledgments
Author
Acronyms
Introduction
Digital Optical Communications and Transmission Systems: Challenging Issues
Enabling Technologies
Modulation Formats and Optical Signal Generation
Advanced Modulation Formats
Incoherent Optical Receivers
DSP-Coherent Optical Receivers
Transmission of Ultra-Short Pulse Sequence
Electronic Equalization
Ultra-Short Pulse Transmission
Organization of the Book Chapters
References
Optical Fibers
Overview
Optical Fiber: General Properties
Geometrical Structures and Index Profile
Fundamental Mode of Weakly Guiding Fibers
Equivalent Step-Index Description
Nonlinear Effects
Nonlinear Self-Phase Modulation Effects
Self-Phase Modulation
Cross-Phase Modulation
Stimulated Scattering Effects
Signal Attenuation in Optical Fibers
Intrinsic or Material Absorption Losses
Waveguide Losses
Attenuation Coefficient
Signal Distortion through Optical Fibers
Material Dispersion
Waveguide Dispersion
Polarization-Mode Dispersion
Transfer Function of Single-Mode Fibers
Linear Transfer Function
Nonlinear Fiber Transfer Function
Transmission Bit Rate and the Dispersion Factor
Fiber Nonlinearity Revisited
SPM and XPM Effects
SPM and Modulation Instability
Effects of Mode Hopping
SPM and Intrachannel Nonlinear Effects
Nonlinear Phase Noises in Cascaded Multispan Optical Link
Special Dispersion Optical Fibers
SMF Transfer Function: Simplified Linear and Nonlinear Operating Region
Numerical Solution: Split-Step Fourier Method
Symmetrical Split-Step Fourier Method
Concluding Remarks
References
Optical Transmitters
Optical Modulators
Phase Modulators
Intensity Modulators
Structures of Photonic Modulators
Operating Parameters of Optical Modulators
Return-to-Zero Optical Pulses
Generation
Phasor Representation
Differential Phase Shift Keying
Background
Optical DPSK Transmitter
Generation of Modulation Formats
Amplitude–Modulation ASK-NRZ and ASK-RZ
Discrete Phase–Modulation NRZ Formats
Continuous Phase–Modulation PM-NRZ Formats
Single-Sideband (SSB) Optical Modulators
Multicarrier Multiplexing Optical Modulators
Spectra of Modulation Formats
Spectral Characteristics of Digital Modulation Formats
I–Q Integrated Modulators
In-Phase and Quadrature-Phase Optical Modulators
I–Q Modulator and Electronic Digital Multiplexing for Ultra-High Bit Rates
Digital-to-Analog Converter for DSP-Based Modulation and Transmitter
Fujitsu DAC
Structure
Generation of I and Q Components
Concluding Remarks
Problems on Tx for Advanced Modulation Formats for Long-Haul Transmission Systems
References
Optical Receivers and Transmission Performance: Fundamentals
Introduction
Digital Optical Receivers
Photonic and Electronic Noise
Performance Evaluation of Binary Amplitude Modulation Format
Received Signals
Probability Distribution Functions
Receiver Sensitivity
OSNR and Noise Impact
Quantum Limit of Optical Receivers under Different Modulation Formats
Direct Detection
Coherent Detection
Coherent Detection with Matched Filter
Binary Coherent Optical Receiver
Noncoherent Detection for Optical DPSK and MSK
Photonic Balanced Receiver
Optical Frequency Discrimination Receiver
Transmission Impairments
Chromatic Dispersion
Chromatic Linear Dispersion
Polarization-Mode Dispersion
Fiber Nonlinearity
MATLAB® and Simulink® Simulator for Optical Communications Systems
Fiber Propagation Model
Nonlinear Effects via Fiber Propagation Model
Performance Evaluation
BER from Monte Carlo Method
BER and Q Factor from Probability Distribution Functions
Histogram Approximation
Optical SNR
Eye Opening Penalty
Statistical Evaluation Techniques
Generalized Pareto Distribution
Novel BER Statistical Techniques
Effects of Source Linewidth
Concluding Remarks
Problems
Appendix: Sellmeier’s Coefficients for Different Core Materials
Appendix: Total Equivalent Electronic Noise
References
Optical Coherent Detection and Processing Systems
Introduction
Coherent Receiver Components
Coherent Detection
Optical Heterodyne Detection
Optical Homodyne Detection
Optical Intradyne Detection
Self-Coherent Detection and Electronic DSP
Electronic Amplifiers: Responses and Noise
Introduction
Wideband TIAs
Amplifier Noise Referred to Input
Digital Signal Processing Systems and Coherent Optical Reception
DSP-Assisted Coherent Detection
Coherent Reception Analysis
Digital Processing Systems
Concluding Remarks
References
Differential Phase Shift Keying Photonic Systems
Introduction
Optical DPSK Modulation and Formats
Generation of RZ Pulses
Phasor Representation
Phasor Representation of CSRZ Pulses
Phasor Representation of RZ33 Pulses
Discrete Phase Modulation—DPSK
DPSK-Balanced Receiver
DPSK Transmission Experiment
Components and Operational Characteristics
Spectra of Modulation Formats
Dispersion Tolerance of Optical DPSK Formats
Optical Filtering Effects
Performance of CSRZ-DPSK over a Dispersion-Managed Optical Transmission Link
Mutual Impact of Adjacent 10G and 40G DWDM Channels
DQPSK Modulation Format
DQPSK
Offset DQPSK Modulation Format
MATLAB® and Simulink® Model
Comparisons of Different Formats and ASK and DPSK
BER and Receiver Sensitivity
Dispersion Tolerance
PMD Tolerance
Robustness toward Nonlinear Effects
Concluding Remarks
Appendix: MATLAB® and Simulink® Model for DQPSK Optical System
References
Multilevel Amplitude and Phase Shift Keying Optical Transmission
Introduction
Amplitude and Differential Phase Modulation
ASK Modulation
Differential Phase Modulation
Comparison of Different Amplitude and Phase Optical Modulation Formats
Multilevel Optical Transmitter Using Single Dual-Drive MZIM Transmitter
MADPSK Optical Transmission
Performance Evaluation
Implementation of MADPSK Transmission Models
Transmitter Model
Receiver Model
Transmission Fiber and Dispersion Compensation Fiber Model
Transmission Performance
Star 16-QAM Optical Transmission
Introduction
Design of 16-QAM Signal Constellation
Signal Constellation
Optimum Ring Ratio for Star Constellation
Detection Methods
Transmitter Design
Receiver for 16-Star QAM
Other Multilevel and Multi-Subcarrier Modulation Formats for 100 Gbps Ethernet Transmission
Concluding Remarks
References
Continuous Phase Modulation Format Optical Systems
Introduction
Generation of Optical MSK-Modulated Signals
Detection of M-ary CPFSK-Modulated Optical Signal
Optical MSK Transmitter Using Parallel I–Q MZIMs
Optical MSK Receivers
Optical Binary Amplitude MSK Format
Generation
Optical MSK
Numerical Results and Discussion
Transmission Performance of Linear and Nonlinear Optical MSK Systems
Transmission Performance of Binary Amplitude Optical MSK Systems
Concluding Remarks
References
Frequency Discrimination Reception for Optical Minimum Shift Keying
Introduction
ONFDR Operational Principles
Receiver Modeling
Receiver Design
Optical Filter Passband
Center Frequency of the Optical Filter
Optimum ODL
ONFDR Optimum Bandwidth and Center Frequency
Receiver Performance: Numerical Validation
ONFDR Robustness to Chromatic Dispersion
Dispersion Tolerance
10 Gbps Transmission
Robustness to PMD of ONFDR
Resilience to Nonlinearity (SPM) of ONFDR
Transmission Limits of OFDR-Based Optical MSK Systems
Dual-Level Optical MSK
Generation Scheme
Incoherent Detection Technique
Optical Power Spectrum
Receiver Sensitivity
Remarks
Concluding Remarks
References
Partial Responses and Single-Sideband Optical Modulation
Partial Responses: Duobinary Modulation Formats
Introduction
DBM Formatter
40 Gbps DB Optical Fiber Transmission Systems
Electro-Optic Duobinary Transmitter
DuoB Encoder
External Modulator
DuoB Transmitters and Precoder
Alternative Phase DB Transmitter
Fiber Propagation
Duobinary Direct Detection Receiver
System Transmission and Performance
DB Encoder
Transmitter
Transmission Performance
Alternating-Phase and Variable-Pulse-Width DuoB: Experimental Setup and Transmission Performance
Remarks
DWDM VSB Modulation-Format Optical Transmission
Transmission System
VSB Filtering and DWDM Channels
Transmission Dispersion and Compensation Fibers
Transmission Performance
Single-Sideband Modulation
Hilbert Transform SSB MZ Modulator Simulation
SSB Demodulator Simulation
Concluding Remarks
References
OFDM Optical Transmission Systems
Introduction
Principles of oOFDM: OFDM as a Multicarrier Modulation Format
FFT- and IFFT-Based OFDM Principles
Optical OFDM Transmission Systems
Impacts on Nonlinear Modulation Effects on Optical OFDM
Dispersion Tolerance
Resilience to PMD Effects
OFDM and DQPSK Formats for 100 Gbps Ethernet
Concluding Remarks
References
Digital Signal Processing in Optical Transmission Systems under Self-Homodyne Coherent Reception
Introduction
Electronic Digital Processing Equalization
System Representation of Equalized Transfer Function
Generic Equalization Formulation
Impulse and Step Responses of the Single-Mode Optical Fiber
Electrical Linear Double-Sampling Equalizers for Duobinary Modulation Formats for Optical Transmission
MLSE Equalizer for Optical MSK Systems
Configuration of MLSE Equalizer in OFDR
MLSE Equalizer with Viterbi Algorithm
MLSE Equalizer with Reduced-State Template Matching
MLSE Scheme Performance
Performance of MLSE Schemes in 40 Gbps Transmission
Transmission of 10 Gbps Optical MSK Signals over 1472 km SSMF Uncompensated Optical Link
Performance Limits of Viterbi-MLSE Equalizers
Viterbi-MLSE Equalizers for PMD Mitigation
On the Uncertainty and Transmission Limitation of Equalization Process
Nonlinear MLSE Equalizers for MSK Optical Transmission Systems
Nonlinear MLSE
Trellis Structure and Viterbi Algorithm
Optical Fiber as an FSM
Uncertainties in Optical Signal Transmission
Uncertainty in ASK Modulation Optical Receiver without Equalization
Uncertainty in MSK Optical Receiver with Equalization
Electronic Dispersion Compensation of Modulation Formats
Concluding Remarks
References
DSP-Based Coherent Optical Transmission Systems
Introduction
Quadrature Phase Shift Keying Systems
Carrier Phase Recovery
112G QPSK Coherent Transmission Systems
I–Q Imbalance Estimation Results
Skew Estimation
Fractionally Spaced Equalization of CD and PMD
Linear, Nonlinear Equalization, and Back Propagation Compensation of Linear and Nonlinear Phase Distortion
16QAM Systems
Terabits/Second Superchannel Transmission Systems
Overview
Nyquist Pulse and Spectra
Superchannel System Requirements
System Structure
Timing Recovery in Nyquist QAM Channel
128 Gbps 16QAM Superchannel Transmission
450 Gbps 32QAM Nyquist Transmission Systems
DSP-Based Heterodyne Coherent Reception Systems
Concluding Remarks
References
DSP Algorithms and Coherent Transmission Systems
Introduction
General Algorithms for Optical Communications Systems
Equalization of DAC-Limited Bandwidth for Tbps Transmission
Linear Equalization
NLE or DFE
Maximum A Posteriori Technique for Phase Estimation
Method
Estimates
Carrier Phase Estimation
Remarks
Correction of Phase Noise and Nonlinear Effects
Forward Phase Estimation QPSK Optical Coherent Receivers
Carrier Recovery in Polarization Division Multiplexed Receivers: A Case Study
Systems Performance of MLSE Equalizer-MSK Optical Transmission Systems
MLSE Equalizer for Optical MSK Systems
MLSE Scheme Performance
Adaptive Joint CR and Turbo Decoding for Nyquist Terabit Optical Transmission in the Presence of Phase Noise
Motivation
Terabit Experiment Setup and Algorithm Principle
References
Optical Soliton Transmission System
Introduction
Fundamentals of Nonlinear Propagation Theory
Numerical Approach
Beam Propagation Method
Analytical Approach—ISM
Fundamental and Higher-Order Solitons
Soliton Evolution for N = 1, 2, 3, 4, and 5
Soliton Breakdown
Interaction of Fundamental Solitons
Two Solitons’ Interaction with Different Pulse Separation
Two Solitons’ Interaction with Different Relative Amplitude
Two Solitons’ Interaction under Different Relative Phases
Triple Solitons’ Interaction under Different Relative Phases
Triple Solitons’ Interaction with Different Relative Phases and r = 1.5
Soliton Pulse Transmission Systems and ISM
ISM Revisited
ISM Solutions for Solitons
N-Soliton Solution (Explicit Formula)
Special Case A = N
N-Soliton Solution (Asymptotic Form as τ→±∞)
Bound States and Multiple Eigenvalues
Interaction between Two Solitons in an Optical Fiber
Soliton Pair with Initial Identical Phases
Soliton Pair with Initial Equal Amplitudes
Soliton Pair with Initial Unequal Amplitudes
Design Strategy
Generation of Bound Solitons
Generation of Bound Solitons in Actively Phase Modulation Mode-Locked Fiber Ring Resonators
Active Harmonic MLFL for Soliton Generation
Concluding Remarks
References
Higher-Order Spectrum Coherent Receivers
Bispectrum Optical Receivers and Nonlinear Photonic Preprocessing
Introductory Remarks
Bispectrum
Bispectrum Coherent Optical Receiver
Triple Correlation and Bispectra
Transmission and Detection
Nonlinear Photonic Signal Processing Using Higher-Order Spectra
Introductory Remarks
FWM and Photonic Processing for Higher-Order Spectra
Third-Order Nonlinearity and Parametric FWM Process
Optical Domain Implementation
Transmission Models and Nonlinear Guided Wave Devices
System Applications of Third-Order Parametric Nonlinearity in Optical Signal Processing
Parametric Amplifiers
Nonlinear Photonic Preprocessing in Coherent Reception Systems
Concluding Remarks
References
Temporal Lens and Adaptive Electronic/Photonic Equalization
Introduction
Space–Time Duality and Equalization
Space–Time Duality
Equalization in Transmission System
Simulation of Transmission and Equalization
Single-Pulse Transmission
Pulse Train Transmission
Equalization of Timing Jitter and PMD
Equalization in 160 Gbps Transmission System
System Overview
Simulation Model Overview
Simulation Results
Concluding Remarks
References
Comparison of Modulation Formats for Digital Optical Communications
Identification of Modulation Features for Combating Impairment Effects
Binary Digital Optical Signals
M-ary Digital Optical Signals
Multi-Subcarrier Digital Optical Signals
Modulation Formats and Electronic Equalization
Amplitude, Phase, and Frequency Modulation Formats in Dispersion-Compensating Span Transmission Systems
ASK—DPSK and DPSK—DQPSK under Self-Homodyne Reception
NRZ-ASK and NRZ-DPSK under Self-Homodyne Reception
RZ-ASK and RZ-DPSK under Self-Homodyne Reception
CSRZ-ASK and CSRZ-DPSK under Self-Homodyne Reception
ASK and DPSK Spectra
ASK and DPSK under Self-Homodyne Reception in Long-Haul Transmission
Nonlinear Effects in ASK and DPSK under Self-Homodyne Reception in Long-Haul Transmission
Performance of DWDM RZ-DPSK and CSRZ-DPSK
Nonlinear Effects on CSRZ-DPSK and RZ-DPSK
Nonlinear Effects on CSRZ-ASK and RZ-ASK
Continuous Phase versus Discrete Phase Shift Keying under Self-Homodyne Reception
Multi-Subcarrier versus Single/Dual Carrier Modulation under Self-Homodyne Reception
Multilevel versus Binary or I–Q Modulation under Self-Homodyne Reception
Single-Sideband and Partial Response Modulation under Self-Homodyne Reception
100 G and Tbps Homodyne Reception Transmission Systems
Generation of Multi-Subcarriers
Nyquist Signal Generation Using DAC by Equalization in Frequency Domain
Function Modules of a Nyquist-WDM System
DSP Architecture
Key Hardware Subsystems
Non-DCF 1 Tbps and 2 Tbps Superchannel Transmission Performance
Multicarrier Scheme Comparison
Modulation Formats and All-Optical Networking
Advanced Modulation Formats in Long-Haul Transmission Systems
Advanced Modulation Formats in All-Optical Networks
Hybrid 40 Gbps over 10 Gbps Optical Networks: 328 km SSMF + DCF for 320 km Tx—Impact of Adjacent 10 G/40 G Channels
Ultra-Fast Optical Networks
Concluding Remarks
References
Annex 1: Technical Data of Single-Mode Optical Fibers
Annex 2: Coherent Balanced Receiver and Method for Noise Suppression
Annex 3: RMS Definition and Power Measurement
Annex 4: Power Budget
Annex 5: Modeling of Digital Photonic Transmission Systems
Index
Biography
Le Nguyen Binh is technical director of Huawei Technologies’ European Research Center, Munich, Germany. He holds a BE (Hons) and Ph.D from the University of Western Australia, Crawley. He has authored and co-authored more than 300 journal papers and eight books, in addition to several refereeing conferences. Previously, he was professorial fellow at Nanyang Technological University of Singapore; the Christian Albrechts University of Kiel, Germany; and several Australian universities. He also served as Chair of Commission D (Electronics and Photonics) of the National Committee for Radio Sciences of the Australian Academy of Sciences (1995–2005).
"This book is excellent and potentially can be used by many universities. … I have not seen that any books are better than this book in this topic."
—John Xiupu Zhang, Concordia University, Montreal, Quebec, Canada"The main strengths of the book are that it is comprehensive, covers the material in depth, and is up-to-date, covering topics which, in many cases, are still being actively investigated by the research community. It provides explicit guidance on the computer simulation of optical communication systems and is very accessible, being well structured and clearly written."
—Robert Killey, University College London