Fiber-optic Communication Systems -- Contents -- Preface -- 1 Introduction -- 1.1 Historical Perspective -- 1.1.1 Need for Fiber-Optic Communications -- 1.1.2 Evolution of Lightwave Systems -- 1.2 Basic Concepts -- 1.2.1 Analog and Digital Signals -- 1.2.2 Channel Multiplexing -- 1.2.3 Modulation Formats -- 1.3 Optical Communication Systems -- 1.4 Lightwave System Components -- 1.4.1 Optical Fibers as a Communication Channel -- 1.4.2 Optical Transmitters -- 1.4.3 Optical Receivers -- Problems -- References -- 2 Optical Fibers -- 2.1 Geometrical-Optics Description -- 2.1.1 Step-Index Fibers -- 2.1.2 Graded-Index Fibers -- 2.2 Wave Propagation -- 2.2.1 Maxwell's Equations -- 2.2.2 Fiber Modes -- 2.2.3 Single-Mode Fibers -- 2.3 Dispersion in Single-Mode Fibers -- 2.3.1 Group-Velocity Dispersion -- 2.3.2 Material Dispersion -- 2.3.3 Waveguide Dispersion -- 2.3.4 Higher-Order Dispersion -- 2.3.5 Polarization-Mode Dispersion -- 2.4 Dispersion-Induced Limitations -- 2.4.1 Basic Propagation Equation -- 2.4.2 Chirped Gaussian Pulses -- 2.4.3 Limitations on the Bit Rate -- 2.4.4 Fiber Bandwidth -- 2.5 Fiber Losses -- 2.5.1 Attenuation Coefficient -- 2.5.2 Material Absorption -- 2.5.3 Rayleigh Scattering -- 2.5.4 Waveguide Imperfections -- 2.6 Nonlinear Optical Effects -- 2.6.1 Stimulated Light Scattering -- 2.6.2 Nonlinear Phase Modulation -- 2.6.3 Four-Wave Mixing -- 2.7 Fiber Design and Fabrication -- 2.7.1 Silica Fibers -- 2.7.2 Plastic Optical Fibers -- 2.7.3 Cables and Connectors -- Problems -- References -- 3 Optical Transmitters -- 3.1 Semiconductor Laser Physics -- 3.1.1 Spontaneous and Stimulated Emissions -- 3.1.2 Nonradiative Recombination -- 3.1.3 Optical Gain -- 3.1.4 Feedback and Laser Threshold -- 3.1.5 Longitudinal Modes -- 3.1.6 Laser Structures -- 3.2 Single-Mode Semiconductor Lasers -- 3.2.1 Distributed Feedback Lasers.

3.2.2 Coupled-Cavity Semiconductor Lasers -- 3.2.3 Tunable Semiconductor Lasers -- 3.2.4 Vertical-Cavity Surface-Emitting Lasers -- 3.3 Laser Characteristics -- 3.3.1 CW Characteristics -- 3.3.2 Modulation Bandwidth -- 3.3.3 Relative Intensity Noise -- 3.3.4 Spectral Linewidth -- 3.4 Optical Signal Generation -- 3.4.1 Direct Modulation -- 3.4.2 External Modulation -- 3.5 Light-Emitting Diodes -- 3.5.1 CW Characteristics -- 3.5.2 Modulation Response -- 3.5.3 LED Structures -- 3.6 Transmitter Design -- 3.6.1 Source-Fiber Coupling -- 3.6.2 Driving Circuitry -- 3.6.3 Reliability and Packaging -- Problems -- References -- 4 Optical Receivers -- 4.1 Basic Concepts -- 4.1.1 Responsivity and Quantum Efficiency -- 4.1.2 Rise Time and Bandwidth -- 4.2 Common Photodetectors -- 4.2.1 p-n Photodiodes -- 4.2.2 p-i-n Photodiodes -- 4.2.3 Avalanche Photodiodes -- 4.2.4 MSM Photodetectors -- 4.3 Receiver Design -- 4.3.1 Front End -- 4.3.2 Linear Channel -- 4.3.3 Decision Circuit -- 4.3.4 Integrated Receivers -- 4.4 Receiver Noise -- 4.4.1 Noise Mechanisms -- 4.4.2 p-i-n Receivers -- 4.4.3 APD Receivers -- 4.5 Coherent Detection -- 4.5.1 Local Oscillator -- 4.5.2 Homodyne Detection -- 4.5.3 Heterodyne Detection -- 4.5.4 Signal-to-Noise Ratio -- 4.6 Receiver Sensitivity -- 4.6.1 Bit-Error Rate -- 4.6.2 Minimum Received Power -- 4.6.3 Quantum Limit of Photodetection -- 4.7 Sensitivity Degradation -- 4.7.1 Extinction Ratio -- 4.7.2 Intensity Noise -- 4.7.3 Timing Jitter -- 4.8 Receiver Performance -- Problems -- References -- 5 Lightwave Systems -- 5.1 System Architectures -- 5.1.1 Point-to-Point Links -- 5.1.2 Distribution Networks -- 5.1.3 Local-Area Networks -- 5.2 Design Guidelines -- 5.2.1 Loss-Limited Lightwave Systems -- 5.2.2 Dispersion-Limited Lightwave Systems -- 5.2.3 Power Budget -- 5.2.4 Rise-Time Budget -- 5.3 Long-Haul Systems.

5.3.1 Performance-Limiting Factors -- 5.3.2 Terrestrial Lightwave Systems -- 5.3.3 Undersea Lightwave Systems -- 5.4 Sources of Power Penalty -- 5.4.1 Modal Noise -- 5.4.2 Mode-Partition Noise -- 5.4.3 Reflection Feedback and Noise -- 5.4.4 Dispersive Pulse Broadening -- 5.4.5 Frequency Chirping -- 5.4.6 Eye-Closure Penalty -- 5.5 Forward Error Correction -- 5.5.1 Error-Correcting Codes -- 5.5.2 Coding Gain -- 5.6 Computer-Aided Design -- Problems -- References -- 6 Multichannel Systems -- 6.1 WDM Lightwave Systems -- 6.1.1 High-Capacity Point-to-Point Links -- 6.1.2 Wide-Area and Metro-Area Networks -- 6.1.3 Multiple-Access WDM Networks -- 6.2 WDM Components -- 6.2.1 Tunable Optical Filters -- 6.2.2 Multiplexers and Demultiplexers -- 6.2.3 Add-Drop Multiplexers and Filters -- 6.2.4 Star Couplers -- 6.2.5 Wavelength Routers -- 6.2.6 WDM Transmitters and Receivers -- 6.3 System Performance Issues -- 6.3.1 Heterowavelength Linear Crosstalk -- 6.3.2 Homowavelength Linear Crosstalk -- 6.3.3 Nonlinear Raman Crosstalk -- 6.3.4 Stimulated Brillouin Scattering -- 6.3.5 Cross-Phase Modulation -- 6.3.6 Four-Wave Mixing -- 6.3.7 Other Design Issues -- 6.4 Time-Division Multiplexing -- 6.4.1 Channel Multiplexing -- 6.4.2 Channel Demultiplexing -- 6.4.3 System Performance -- 6.5 Subcarrier Multiplexing -- 6.5.1 Analog and Digital SCM Systems -- 6.5.2 Multiwavelength SCM Systems -- 6.5.3 Orthogonal Frequency-Division multiplexing -- 6.6 Code-Division Multiplexing -- 6.6.1 Time-Domain Encoding -- 6.6.2 Frequency-Domain Encoding -- 6.6.3 Frequency Hopping -- Problems -- References -- 7 Loss Management -- 7.1 Compensation of Fiber Losses -- 7.1.1 Periodic Amplification Scheme -- 7.1.2 Lumped Versus Distributed Amplification -- 7.1.3 Bidirectional Pumping Scheme -- 7.2 Erbium-Doped Fiber Amplifiers -- 7.2.1 Pumping and Gain Spectrum -- 7.2.2 Two-Level Model.

7.2.3 Amplifier Noise -- 7.2.4 Multichannel Amplification -- 7.3 Raman Amplifiers -- 7.3.1 Raman Gain and Bandwidth -- 7.3.2 Raman-Induced Signal Gain -- 7.3.3 Multiple-Pump Raman Amplification -- 7.3.4 Noise Figure of Raman Amplifiers -- 7.4 Optical Signal-To-Noise Ratio -- 7.4.1 Lumped Amplification -- 7.4.2 Distributed Amplification -- 7.5 Electrical Signal-To-Noise Ratio -- 7.5.1 ASE-Induced Current Fluctuations -- 7.5.2 Impact of ASE on SNR -- 7.5.3 Noise Buildup in an Amplifier Chain -- 7.6 Receiver Sensitivity and Q Factor -- 7.6.1 Bit-Error Rate -- 7.6.2 Relation between Q Factor and Optical SNR -- 7.7 Role of Dispersive and Nonlinear Effects -- 7.7.1 Noise Growth through Modulation Instability -- 7.7.2 Noise-Induced Signal Degradation -- 7.7.3 Noise-Induced Energy Fluctuations -- 7.7.4 Noise-Induced Timing Jitter -- 7.8 Periodically Amplified Lightwave Systems -- 7.8.1 Numerical Approach -- 7.8.2 Optimum Launched Power -- Problems -- References -- 8 Dispersion Management -- 8.1 Dispersion Problem and Its Solution -- 8.2 Dispersion-Compensating Fibers -- 8.2.1 Conditions for Dispersion Compensation -- 8.2.2 Dispersion Maps -- 8.2.3 DCF Designs -- 8.3 Fiber Bragg Gratings -- 8.3.1 Constant-Period Gratings -- 8.3.2 Chirped Fiber Gratings -- 8.3.3 Sampled Gratings -- 8.4 Dispersion-Equalizing Filters -- 8.4.1 Gires-Tournois Filters -- 8.4.2 Mach-Zehnder Filters -- 8.4.3 Other All-Pass Filters -- 8.5 Optical Phase Conjugation -- 8.5.1 Principle of Operation -- 8.5.2 Compensation of Self-Phase Modulation -- 8.5.3 Generation of Phase-Conjugated Signal -- 8.6 Channels at High Bit Rates -- 8.6.1 Tunable Dispersion Compensation -- 8.6.2 Higher-Order Dispersion Management -- 8.6.3 PMD Compensation -- 8.7 Electronic Dispersion Compensation -- 8.7.1 Basic Idea behind GVD Precompensation -- 8.7.2 Precompensation at the Transmitter.

8.7.3 Dispersion Compensation at the Receiver -- Problems -- References -- 9 Control of Nonlinear Effects -- 9.1 Impact of Fiber Nonlinearity -- 9.1.1 System Design Issues -- 9.1.2 Semianalytic Approach -- 9.1.3 Soliton and Pseudo-linear Regimes -- 9.2 Solitons in Optical Fibers -- 9.2.1 Properties of Optical Solitons -- 9.2.2 Loss-Managed Solitons -- 9.3 Dispersion-Managed Solitons -- 9.3.1 Dispersion-Decreasing Fibers -- 9.3.2 Periodic Dispersion Maps -- 9.3.3 Design Issues -- 9.3.4 Timing Jitter -- 9.3.5 Control of Timing Jitter -- 9.4 Pseudo-linear Lightwave Systems -- 9.4.1 Origin of Intrachannel Nonlinear Effects -- 9.4.2 Intrachannel Cross-Phase Modulation -- 9.4.3 Intrachannel Four-Wave Mixing -- 9.5 Control of Intrachannel Nonlinear Effects -- 9.5.1 Optimization of Dispersion Maps -- 9.5.2 Phase-Alternation Techniques -- 9.5.3 Polarization Bit Interleaving -- Problems -- References -- 10 Advanced Lightwave Systems -- 10.1 Advanced Modulation Formats -- 10.1.1 Encoding of Optical Signals -- 10.1.2 Amplitude and Phase Modulators -- 10.2 Demodulation Schemes -- 10.2.1 Synchronous Heterodyne Demodulation -- 10.2.2 Asynchronous Heterodyne Demodulation -- 10.2.3 Optical Delay Demodulation -- 10.3 Shot Noise and Bit-Error Rate -- 10.3.1 Synchronous Heterodyne Receivers -- 10.3.2 Asynchronous Heterodyne Receivers -- 10.3.3 Receivers with Delay Demodulation -- 10.4 Sensitivity Degradation Mechanisms -- 10.4.1 Intensity Noise of Lasers -- 10.4.2 Phase Noise of Lasers -- 10.4.3 Signal Polarization Fluctuations -- 10.4.4 Noise Added by Optical Amplifiers -- 10.4.5 Fiber Dispersion -- 10.5 Impact of Nonlinear Effects -- 10.5.1 Nonlinear Phase Noise -- 10.5.2 Effect of Fiber Dispersion -- 10.5.3 Compensation of Nonlinear Phase Noise -- 10.6 Recent Progress -- 10.6.1 Systems with the DBPSK format -- 10.6.2 Systems with the DQPSK format.

10.6.3 QAM and Related formats.