List of Contributors xv Preface xvii 1 Introduction 1 Xiang Zhou and Chongjin Xie 1.1 High-Capacity Fiber Transmission Technology Evolution, 1 1.2 Fundamentals of Coherent Transmission Technology, 4 1.2.1 Concept of Coherent Detection, 4 1.2.2 Digital Signal Processing, 5 1.2.
3 Key Devices, 7 1.3 Outline of this Book, 8 References, 9 2 Multidimensional Optimized Optical Modulation Formats 13 Magnus Karlsson and Erik Agrell 2.1 Introduction, 13 2.2 Fundamentals of Digital Modulation, 15 2.2.1 System Models, 15 2.2.2 Channel Models, 17 2.
2.3 Constellations and Their Performance Metrics, 18 2.3 Modulation Formats and Their Ideal Performance, 20 2.3.1 Format Optimizations and Comparisons, 21 2.3.2 Optimized Formats in Nonlinear Channels, 30 2.4 Combinations of Coding and Modulation, 31 2.
4.1 Soft-Decision Decoding, 31 2.4.2 Hard-Decision Decoding, 37 2.4.3 Iterative Decoding, 39 2.5 Experimental Work, 40 2.5.
1 Transmitter Realizations and Transmission Experiments, 40 2.5.2 Receiver Realizations and Digital Signal Processing, 45 2.5.3 Formats Overview, 49 2.5.4 Symbol Detection, 50 2.5.
5 Realizing Dimensions, 51 2.6 Summary and Conclusions, 54 References, 56 3 Advances in Detection and Error Correction for Coherent Optical Communications: Regular, Irregular, and Spatially Coupled LDPC Code Designs 65 Laurent Schmalen, Stephan ten Brink, and Andreas Leven 3.1 Introduction, 65 3.2 Differential Coding for Optical Communications, 67 3.2.1 Higher-Order Modulation Formats, 67 3.2.2 The Phase-Slip Channel Model, 69 3.
2.3 Differential Coding and Decoding, 71 3.2.4 Maximum a Posteriori Differential Decoding, 78 3.2.5 Achievable Rates of the Differentially Coded Phase-Slip Channel, 81 3.3 LDPC-Coded Differential Modulation, 83 3.3.
1 Low-Density Parity-Check (LDPC) Codes, 85 3.3.2 Code Design for Iterative Differential Decoding, 91 3.3.3 Higher-Order Modulation Formats with V Rs), 128 4.2.3 Super-Nyquist-WDM (Îf < Rs), 130 4.3 Detection of a Nyquist-WDM Signal, 134 4.
4 Practical Nyquist-WDM Transmitter Implementations, 137 4.4.1 Optical Nyquist-WDM, 139 4.4.2 Digital Nyquist-WDM, 141 4.5 Nyquist-WDM Transmission, 146 4.5.1 Optical Nyquist-WDM Transmission Experiments, 148 4.
5.2 Digital Nyquist-WDM Transmission Experiments, 148 4.6 Conclusions, 149 References, 150 5 Spectrally Efficient Multiplexing - OFDM 157 An Li, Di Che, Qian Hu, Xi Chen, and William Shieh 5.1 OFDM Basics, 158 5.2 Coherent Optical OFDM (CO-OFDM), 161 5.2.1 Principle of CO-OFDM, 161 5.3 Direct-Detection Optical OFDM (DDO-OFDM), 169 5.
3.1 Linearly Mapped DDO-OFDM, 169 5.3.2 Nonlinearly Mapped DDO-OFDM (NLM-DDO-OFDM), 173 5.4 Self-Coherent Optical OFDM, 174 5.4.1 Single-Ended Photodetector-Based SCOH, 175 5.4.
2 Balanced Receiver-Based SCOH, 177 5.4.3 Stokes Vector Direct Detection, 177 5.5 Discrete Fourier Transform Spread OFDM System (DFT-S OFDM), 180 5.5.1 Principle of DFT-S OFDM, 180 5.5.2 Unique-Word-Assisted DFT-S OFDM (UW-DFT-S OFDM), 182 5.
6 OFDM-Based Superchannel Transmissions, 183 5.6.1 No-Guard-Interval CO-OFDM (NGI-CO-OFDM) Superchannel, 184 5.6.2 Reduced-Guard-Interval CO-OFDM (RGI-CO-OFDM) Superchannel, 186 5.6.3 DFT-S OFDM Superchannel, 188 5.7 Summary, 193 References, 194 6 Polarization and Nonlinear Impairments in Fiber Communication Systems 201 Chongjin Xie 6.
1 Introduction, 201 6.2 Polarization of Light, 202 6.3 PMD and PDL in Optical Communication Systems, 206 6.3.1 PMD, 206 6.3.2 PDL, 208 6.4 Modeling of Nonlinear Effects in Optical Fibers, 209 6.
5 Coherent Optical Communication Systems and Signal Equalization, 211 6.5.1 Coherent Optical Communication Systems, 211 6.5.2 Signal Equalization, 213 6.6 PMD and PDL Impairments in Coherent Systems, 215 6.6.1 PMD Impairment, 216 6.
6.2 PDL Impairment, 222 6.7 Nonlinear Impairments in Coherent Systems, 228 6.7.1 System Model, 229 6.7.2 Homogeneous PDM-QPSK System, 230 6.7.
3 Hybrid PDM-QPSK and 10-Gb/s OOK System, 233 6.7.4 Homogeneous PDM-16QAM System, 234 6.8 Summary, 240 References, 241 7 Analytical Modeling of the Impact of Fiber Non-Linear Propagation on Coherent Systems and Networks 247 Pierluigi Poggiolini, Yanchao Jiang, Andrea Carena, and Fabrizio Forghieri 7.1 Why are Analytical Models Important?, 247 7.1.1 What Do Professionals Need?, 247 7.2 Background, 248 7.
2.1 Modeling Approximations, 249 7.3 Introducing the GN-EGN Model Class, 260 7.3.1 Getting to the GN Model, 260 7.3.2 Towards the EGN Model, 265 7.4 Model Selection Guide, 269 7.
4.1 From Model to System Performance, 269 7.4.2 Point-to-Point Links, 270 7.4.3 The Complete EGN Model, 272 7.4.4 Case Study: Determining the Optimum System Symbol Rate, 286 7.
4.5 NLI Modeling for Dynamically Reconfigurable Networks, 289 7.5 Conclusion, 294 Acknowledgements, 295 Appendix, 295 A.1 The White-Noise Approximation, 295 A.1 BER Formulas for the Most Common QAM Systems, 295 A.2 The Link Function , 296 A.3 The EGN Model Formulas for the X2-X4 and M1-M3 Islands, 297 A.4 Outline of GN-EGN Model Derivation, 299 A.
5 List of Acronyms, 303 References, 305 8 Digital Equalization in Coherent Optical Transmission Systems 311 Seb Savory 8.1 Introduction, 311 8.2 Primer on the Mathematics of Least Squares FIR Filters, 312 8.2.1 Finite Impulse Response Filters, 313 8.2.2 Differentiation with Respect to a Complex Vector, 314 8.2.
3 Least Squares Tap Weights, 314 8.2.4 Application to Stochastic Gradient Algorithms, 316 8.2.5 Application to Wiener Filter, 317 8.2.6 Other Filtering Techniques and Design Methodologies, 318 8.3 Equalization of Chromatic Dispersion, 318 8.
3.1 Nature of Chromatic Dispersion, 318 8.3.2 Modeling of Chromatic Dispersion in an Optical Fiber, 318 8.3.3 Truncated Impulse Response, 319 8.3.4 Band-Limited Impulse Response, 320 8.
3.5 Least Squares FIR Filter Design, 321 8.3.6 Example Performance of the Chromatic Dispersion Compensating Filter, 321 8.4 Equalization of Polarization-Mode Dispersion, 323 8.4.1 Modeling of PMD, 324 8.4.
2 Obtaining the Inverse Jones Matrix of the Channel, 325 8.4.3 Constant Modulus Update Algorithm, 325 8.4.4 Decision-Directed Equalizer Update Algorithm, 326 8.4.5 Radially Directed Equalizer Update Algorithm, 327 8.4.
6 Parallel Realization of the FIR Filter, 327 8.4.7 Generalized 4 Ã 4 Equalizer for Mitigation of Frequency or Polarization-Dependent Loss and Receiver Skew, 328 8.4.8 Example Application to Fast Blind Equalization of PMD, 328 8.5 Concluding Remarks and Future Research Directions, 329 Acknowledgments, 330 References, 330 9 Nonlinear Compensation for Digital Coherent Transmission 333 Guifang Li 9.1 Introduction, 333 9.2 Digital Backward Propagation (DBP), 334 9.
2.1 How DBP Works, 334 9.2.2 Experimental Demonstration of DBP, 335 9.2.3 Computational Complexity of DBP, 336 9.3 Reducing DBP Complexity for Dispersion-Unmanaged WDM Transmission, 339 9.4 DBP for Dispersion-Managed WDM Transmission, 342 9.
5 DBP for Polarization-Multiplexed Transmission, 349 9.6 Future Research, 350 References, 351 10 Timing Synchronization in Coherent Optical Transmission Systems 355 Han Sun and Kuang-Tsan Wu 10.1 Introduction, 355 10.2 Overall System Environment, 357 10.3 Jitter Penalty and Jitter Sources in a Coherent System, 359 10.3.1 VCO Jitter, 359 10.3.
2 Detector Jitter Definitions and Method of Numerical Evaluation, 361 10.3.3 Laser FM Noise- and Dispersion-Induced Jitter, 363 10.3.4 Coherent System Tolerance to Untracked Jitter, 366 10.4 Digital Phase Detectors, 368 10.4.1 Frequency-Domain Phase Detector, 369 10.
4.2 Equivalence to the Squaring Phase Detector, 371 10.4.3 Equivalence to Godard''s Maximum Sampled Power Criterion, 373 10.4.4 Equivalence to Gardner''s Phase Detector, 374 10.4.5 Second Class of Phase Detectors, 377 10.
4.6 Jitter Performance of the Phase Detectors, 378 10.4.7 Phase Detectors for Nyquist Signals, 380