Preface xvi About the Editors xviii List of Contributors xix Part A Introduction 1 Introduction 3Sandip Nandi and Dalia Nandi A. Optical Communication Networks 3 A.1 Historical Perspective 3 A.2 Essential Background 6 A.2.1 Optical Networks 6 A.2.2 SONET/SDH 6 A.2.3 Multiplexing 7 A.2.4 All-Optical Networks 7 A.2.5 Optical Transport Network 8 B. Optical Switching in Networks 8 B.1 Historical Perspective 8 B.2 Essential Background 9 B.2.1 Optical Switching in Networks 9 B.2.2 Optical Switching in Practice 9 B.2.3 Optical Switch Technology 10 C. Organization of This Book 10 Bibliography 11 Part B Switch Characterization 13 1 Optical Switches 15Rajan Agrahari, Sambit Kumar Ghosh, and Somak Bhattacharyya 1.1 Introduction 15 1.2 Electro-Optical Switching 16 1.2.1 Working Principle of Electro-Optical Switches 16 1.2.2 Realization of Electro-Optical Switches 17 1.3 Acoustic-Optical Switching 18 1.3.1 Types of Acoustic-Optical Switching 18 1.3.2 Acoustic-Optical Device Materials and Applications 19 1.4 Thermo-Optical Switching 19 1.4.1 Working Principle of Thermo-Optical Switches 20 1.4.2 Realization of Thermo-Optical Switches 20 1.4.3 Thermo-Optical Switch Materials and Applications 21 1.5 Liquid Crystal-Optical Switching 21 1.5.1 Types of Liquid Crystal-Optical Switches 21 1.5.2 Liquid Crystal-Optical Switch Applications 22 1.6 Photonic Crystal Optical Switching 22 1.7 Semiconductor Optical Amplifier (SOA) Optical Switching 23 1.8 Magneto-Optical (MO) Optical Switching 25 1.9 Micro Electro-Mechanical Systems (MEMS) Optical Switching 25 1.10 Metasurfaces Switches 26 1.11 Conclusion 26 Bibliography 27 2 Electro-Optic Switches 31Arpita Adhikari, Joydip Sengupta, and Arijit De 2.1 Introduction 31 2.2 Operating Principles 32 2.2.1 Operating Principles of the Single-Mode Switch 32 2.2.2 Operating Principles of the Multimode Switch 32 2.3 Materials for the Fabrication of Electro-Optic Switch 34 2.3.1 Ferroelectric Materials 34 2.3.2 Compound Semiconductors 35 2.3.3 Polymers 35 2.4 Device Structures of Electro-Optical Switches 36 2.4.1 1 × 1 Switch 36 2.4.2 1 × 2 Switch 37 2.4.3 2 × 2 Switch 39 2.4.4 2 × 3 Switch 40 2.4.5 3 × 2 Switch 41 2.4.6 3 × 3 Switch 42 2.4.7 1 × 4 Switch 42 2.4.8 2 × 4 Switch 43 2.5 Conclusions 43 Bibliography 44 3 Thermo-Optical Switches 47Fulong Yan, Xuwei Xue, and Chongjin Xie 3.1 History of Thermal Optical Switching 47 3.2 Principles of Thermo-Optic Switch 47 3.2.1 Thermo-Optic Effect 47 3.2.2 Trade-Off Between Switching Time and Power Consumption 48 3.2.3 Merits of Thermo-Optic Switch 49 3.3 Category 49 3.3.1 Material 49 3.3.2 Implementation Principle 51 3.3.3 Device Architecture 51 3.4 Scalability 52 3.4.1 Binary Tree 52 3.4.2 Modified Crossbar 53 3.4.3 Benes 54 3.5 Application Scenarios 54 Bibliography 55 4 Magneto-Optical Switches 57K. Sujatha 4.1 Introduction 57 4.1.1 Types of Optical Switch 57 4.1.2 How Does an Optical Switch Work? 59 4.1.3 Applications of Optical Switches 59 4.2 All-Optical Switch 60 4.2.1 Why is an All-Optical Switch Useful? 62 4.3 Magneto-Optical Switches 64 4.3.1 Magneto-Optical Switch Features 64 4.3.2 Principles of Magneto-Optical Switches 65 4.3.2.1 The Design Core of the Magneto-Optical Switch 65 4.3.3 Magneto-Optic Effect 66 4.4 Faraday Rotation 68 4.4.1 Phenomenological Model 68 4.4.2 Atomic Model 68 Bibliography 70 Further Reading 70 5 Acousto-Optic Switches 73Sudipta Ghosh, Chandan Kumar Sarkar, and Manash Chanda 5.1 Introduction 73 5.2 Fundamentals of Acousto-Optic Effect 73 5.3 Acousto-Optic Diffraction 74 5.4 Raman–Nath Diffraction 76 5.5 Bragg Diffraction 77 5.6 Principle of Operation of AO Switches 78 5.7 Acousto-Optic Modulator 80 5.7.1 Acousto-Optic Q-Switching 81 5.7.2 Telecommunication Network 82 5.8 Recent Trends and Applications 83 5.8.1 Emerging Spatial Mode Conversion in Few-Mode Fibers 83 5.8.2 Lithium Niobate Thin Films 84 5.8.3 Optical Fiber Communication and Networking 85 Bibliography 86 6 MEMS-based Optical Switches 93Kalyan Biswas and Angsuman Sarkar 6.1 Introduction 93 6.2 Micromachining Techniques 94 6.2.1 Bulk Micromachining 95 6.2.2 Surface Micromachining 95 6.3 Switch Architectures 97 6.3.1 One-Dimensional Switches 97 6.3.2 Two-Dimensional MEMS Switches 97 6.3.3 Three-Dimensional MEMS Switches 98 6.4 Mechanisms of Actuations 100 6.4.1 Electrostatic Actuation 100 6.4.2 Magnetic Actuation 100 6.4.3 Thermal Actuation 100 6.4.4 Piezoelectric Actuation Mechanisms 100 6.4.5 Other Actuation Mechanisms 101 6.5 Optical Switch Parameters 101 6.5.1 Switching Time 102 6.5.2 Insertion Loss 102 6.5.3 Crosstalk 102 6.5.4 Wavelength 102 6.5.5 Power Consumption 102 6.6 Challenges 103 6.6.1 Optical Beam Divergence 103 6.6.2 Angular Control 103 6.6.3 Reliability of Optical MEMS 103 6.7 Conclusion 104 Bibliography 104 7 SOA-based Optical Switches 107Xuwei Xue, Shanguo Huang, Bingli Guo, and Nicola Calabretta 7.1 Introduction 107 7.2 SOA Structure 107 7.2.1 Active Region 108 7.2.2 Inter-Band Versus Intra-Band Transition 109 7.2.3 Transparency Threshold 110 7.2.4 Gain Nonlinearity 111 7.2.5 Polarization-Insensitive SOA 111 7.2.6 Noise in SOA 112 7.3 Design Criteria of SOA-Based Switch 113 7.3.1 Effect of Doping on Gain Dynamics 113 7.3.2 Gain Dynamic for SOA 115 7.3.2.1 Bulk-Active Regions 116 7.3.2.2 Quantum Well/Multi-Quantum Well (MQW) Active Regions 116 7.3.2.3 Quantum Dots 116 7.3.3 Noise Suppression 117 7.3.4 Scalability 118 7.4 Advancements on SOA-Based Switch 120 7.5 Networks Employing SOA-Based Switch 122 7.5.1 Metro-Access Network 122 7.5.2 RF Network 122 7.5.3 Silicon Photonic Switching 122 7.5.4 Data Center Network 123 7.6 Discussion and Future Work 123 Bibliography 124 8 Liquid Crystal Switches 129Swarnil Roy and Manash Chanda 8.1 Introduction 129 8.2 Liquid Crystal and Its Properties 131 8.3 LC Structures for Optical Switching 131 8.3.1 Twisted Nematic (TN) cells 131 8.3.2 Surface-Stabilized Ferroelectric Liquid Crystal (SSFLC) Cells 133 8.3.3 Spatial Light Modulator (SLM) Cells 133 8.4 Liquid Crystal Switches 134 8.4.1 Optical Crystal Switching Architectures 134 8.4.2 Switches Based on Polarization 135 8.4.2.1 Performance Analysis of Polarization-Based Switch Architecture 136 8.4.3 LC Amplitude and Phase Modulator 138 8.4.4 LC-Based Wavelength-Selective Switches (WSS) 140 8.4.4.1 WSS Based on LCOS 141 8.5 The Future of LC switches 141 8.5.1 Liquid Crystal Photonic Crystal Fibers 141 8.5.2 Ring Resonators with LC 142 Bibliography 142 9 Photonic Crystal All-Optical Switches 147Rashmi Kumari, Anjali Yadav, and Basudev Lahiri 9.1 Idea of Photonics 147 9.2 Principles of Photonic Crystal All-Optical Switches (AOS) 148 9.3 Growth and Characterization of Optical Quantum Dots 150 9.3.1 Integration of PhCs-Based AOS with Optical Quantum Dots (QDs) 150 9.3.2 Growth and Characterization of Quantum Dots 152 9.3.2.1 Growth of Quantum Dots 152 9.3.2.2 Colloidal Solution Via Chemical Synthesis 152 9.3.2.3 Self-Assembly Technique 153 9.3.2.4 Characterization of Quantum Dots 154 9.3.2.5 Photoluminescence Spectroscopy 154 9.3.2.6 UV-Vis Spectroscopy 154 9.4 Design and Fabrication 155 9.4.1 Sample Preparation 155 9.4.2 Lithography 155 9.4.2.1 Electron Beam Lithography (EBL) 155 9.4.2.2 Optical UV Lithography 155 9.4.3 Etching 155 9.4.3.1 Wet Etching 155 9.4.3.2 Dry Etching 156 9.5 Device Structure and Performance Analysis of Photonic Crystal All-Optical Switches 156 9.6 Challenges and Recent Research Trends of Photonic Crystal All-Optical Switches 159 Bibliography 160 10 Optical-Electrical-Optical (O-E-O) Switches 165Piyali Mukherjee 10.1 Introduction 165 10.2 Optical Switching Technologies: Working Principle 166 10.2.1 Optical-Electrical-Optical Switching 166 10.2.2 Optical Data Unit Switching 167 10.2.3 Reconfigurable Optical Add-Drop Multiplexer (ROADM)-Based Switching 168 10.2.4 A hybrid approach 169 10.3 Optical Transponders 169 10.3.1 WDM Transponders: An Introduction 169 10.3.2 Basic Working of Optical Transponders 170 10.3.3 Necessity of Optical Transponder (OEO) in WDM System 171 10.3.4 Applications of Optical Transponders 171 10.3.5 Network Structure with Optical Transponder 172 10.3.5.1 WDM Ring Employing Line Network 172 10.3.5.2 WDM Ring Employing Star Network 172 10.3.6 Differences Between Transponder, Muxponder, and Transceiver 173 10.3.7 Summary 174 10.4 Performance Analysis Study of All-Optical Switches, Electrical Switches, and Hybrid Switches in Networks 174 10.4.1 Introduction 174 10.4.2 Optical vs. Electrical vs. Hybrid Telecom Switches 175 10.4.3 Optical vs. Electrical vs. Hybrid Data Center Switches 177 10.4.4 Summary 179 10.5 Electrical and Optoelectronic Technology for Promoting Connectivity in Future Systems 179 10.5.1 CMOS Technology 180 10.5.2 Considerations for Selection of Interconnects 180 10.6 Conclusion 181 Bibliography 181 11 Quantum Optical Switches 185Surabhi Yadav and Aranya B. Bhattacherjee 11.1 Introduction 185 11.2 Quantum Dot as an Optical Switch 186 11.2.1 Vertical Cavities 187 11.2.2 Power Density 189 11.3 Quantum Well as an Optical Switch 191 11.3.1 Optical Properties 191 11.3.2 Self-Electro-Optic-Effect Devices 193 11.4 Optomechanical Systems as Optical Switch 193 11.4.1 Optical Nonlinearity 193 11.4.2 Hybrid Optomechanics 195 11.4.3 Electro-opto Mechanics 198 11.5 Conclusion and Future Outlook 198 Bibliography 199 12 Nonlinear All-Optical Switch 203Rajarshi Dhar, Arpan Deyasi, and Angsuman Sarkar 12.1 Introduction 203 12.2 Classification of All-Optical Switches 203 12.2.1 Thermo-Optical Switch 203 12.2.2 Acousto-Optic Switch 204 12.2.3 Liquid Crystal Optical Switch 206 12.2.4 Nonlinear Optical Switch 207 12.3 Classification of Nonlinear All-Optical Switches 207 12.3.1 Optical Coupler AOS 208 12.3.2 Sagnac Interferometer AOS 210 12.3.3 M–Z Interferometer AOS 210 12.3.4 Ring Resonator AOS 211 12.3.5 Fiber Grating AOS 212 12.4 Working Methodology of Different Types of Nonlinear All-Optical Switches 212 12.4.1 Optical Coupler AOS 212 12.4.1.1 Symmetric Coupler Working at Low Incident Power 213 12.4.1.2 Symmetric Coupler Working in High-Power Incident Light with SPM 214 12.4.1.3 Asymmetric Coupler Working in High-Power Pump Light with Cross-phase Modulation 217 12.4.2 Sagnac Interferometer AOS 219 12.4.2.1 Sagnac Interferometer (SI) Under Low Incident Power 219 12.4.2.2 Sagnac Interferometer AOS with Non-3dB Coupler 220 12.4.2.3 Sagnac Interferometer AOS in Cross-Phase Modulation 221 12.4.2.4 Sagnac Interferometer AOS with Optical Amplifier 222 12.4.3 M–Z Interferometer AOS 223 12.4.3.1 M–Z Interferometer AOS with Different Arm Materials 223 12.4.3.2 M–Z Interferometer All-Optical Switch with Different Arm Lengths 224 12.4.4 Ring Resonator AOS 225 12.4.4.1 AOS in M–Z Interferometer Coupled with SCRR 225 12.4.4.2 AOS in DCRR 227 12.4.5 Fiber Grating AOS 229 12.4.5.1 Single Nonlinear FBG AOS 229 12.4.5.2 Single Nonlinear LPFG AOS 231 12.5 Nanoscale AOS 233 12.6 Future Scope and Conclusion 234 Bibliography 235 13 Silicon Photonic Switches 239Nadir Ali, Mohammad Faraz Abdullah, and Rajesh Kumar 13.1 Introduction 239 13.2 Performance Parameters 239 13.3 Silicon Photonic Platform 240 13.4 Physical Principles for Operation of Switches 241 13.4.1 Electro-optic Effect 242 13.4.2 Carrier Injection/Extraction 242 13.4.3 Thermo-optic Effect 242 13.4.4 All-optical Effect 243 13.5 Major Configurations 244 13.5.1 Directional Coupler 244 13.5.2 Microring Resonator 245 13.5.3 Mach–Zehnder Interferometer 246 13.5.4 Micro-Electro-Mechanical System 247 13.6 Hybrid Silicon Photonic Switches 248 13.6.1 III-V Materials 248 13.6.2 2D Materials 248 13.6.3 Phase Change Materials 249 13.7 Switch Fabrics Using MRR and MZI 252 13.8 Summary 252 Bibliography 252 Part C Application of Optical Switches in Networks 257 14 Switch Control: Bridging the Last Mile for Optical Data Centers 259Nicola Calabretta and Xuwei Xue 14.1 Introduction 259 14.2 Switch Control Classification 260 14.2.1 Electrical Switch Control 260 14.2.2 Slow Optical Switch Control 261 14.2.3 Fast Optical Switch Control 262 14.3 Challenges for Switch Fabric Control 264 14.3.1 Scalable Control Plane 264 14.3.2 Precise Time Synchronization 265 14.3.3 Fast Burst Clock Data Recovery 266 14.3.4 Lack of Optical Buffer 267 14.3.5 Reliability 268 14.4 Switch Fabric Control: State of the Art 268 14.4.1 Predefined Control 268 14.4.2 SDN Control 268 14.4.3 Label Control 270 14.4.4 AI Control 271 Bibliography 272 15 Reliability in Optical Networks 277Antony Gratus Varuvel and Rajendra Prasath 15.1 Introduction 277 15.2 RAMS in Optical Networks 278 15.3 Objectives 278 15.4 Life Cycle of a Product/Project 278 15.5 Preamble to RAMS 279 15.5.1 Reliability 280 15.5.2 Availability 281 15.5.3 Maintainability 281 15.5.4 System Safety 281 15.6 Significance of Reliability in Optical Interconnect Systems 282 15.7 Typical Components of Optical Circuitry 282 15.8 Generic Types of Optical System 284 15.8.1 Factors Influencing Reliability in Optical Networks 284 15.8.2 Initial Insight of Failures 284 15.9 Ensuring RAMS for the Optical System 285 15.9.1 Reliability – An Essential Insight 285 15.9.1.1 Typical Reliability Configurations 286 15.9.1.2 Reliability Metrics 287 15.9.1.3 Reliability Apportionment 292 15.9.1.4 Hardware Reliability Prediction 292 15.9.1.5 Software Reliability Prediction 294 15.9.1.6 Derating Analysis 294 15.9.1.7 Stress-Strength Interference Analysis 294 15.9.1.8 Reliability Estimation 295 15.9.1.9 Failure Mode Effects and Criticality Analysis 295 15.9.1.10 Failure Mode Effects Test Cases 296 15.9.1.11 Reliability Assessment/Demonstration 297 15.9.1.12 Human Error Analysis 297 15.9.1.13 Reliability Growth Analysis 297 15.9.1.14 Life Data Analysis 298 15.9.1.15 Physics of Failure 298 15.9.1.16 Design-Cost Trade-off 299 15.9.2 Availability Measures of Optical Networks 299 15.9.2.1 Availability Assessment 299 15.9.2.2 Reliability-Centered Maintenance 300 15.9.2.3 Competing Failure Modes 301 15.9.2.4 Warranty Analysis 301 15.9.2.5 Trend Analysis 302 15.9.3 Maintainability Aspects of Optical Networks 302 15.9.3.1 Maintainability Apportionment 302 15.9.3.2 Maintainability Assessment 303 15.9.3.3 Maintainability Demonstration 303 15.9.3.4 Maintainability Estimation/Evaluation 303 15.9.3.5 Maintainability Prediction 303 15.9.3.6 Maintenance Strategy [Plan/Philosophy] 303 15.9.3.7 Spare Parts Optimization 304 15.9.3.8 Failure Reporting and Corrective Action System 304 15.9.4 Optical Networks for Safety-Critical Applications 304 15.9.4.1 Common Cause Analysis 305 15.9.4.2 Common Mode Analysis 307 15.9.4.3 Fault Tree Analysis 307 15.9.4.4 Functional Hazard Analysis 308 15.9.4.5 Hazard and Operability Studies 308 15.9.4.6 Zonal Safety Analysis 309 15.9.4.7 Particular Risk Assessment 309 15.9.4.8 Software Risk Assessment 309 15.9.4.9 Event Tree Analysis 310 15.10 Process Control in Optical Components 310 15.11 Hardware – Software Interactions (HSI) in Optical Networks 310 15.12 Typical RAMS Realisation Plan for an Optical System 311 15.12.1 System-level RAMS Activities 311 15.12.2 Item-level RAMS Activities 312 15.13 Trade-off Factors of Optical Networks 314 15.14 Some Open Problems in RAMS-Optical System 314 15.15 Conclusion 314 Bibliography 315 16 Protection, Restoration, and Improvement 317Arighna Basak and Angsuman Sarkar 16.1 Introduction 317 16.2 Objectives of Protection and Restoration 319 16.3 Current Fault Protection and Restoration Techniques 319 16.3.1 Link Protection 320 16.3.2 Path Protection 321 16.3.2.1 Current Fault Protection Techniques 321 16.3.2.2 Path Protection in Mesh Network 321 16.3.2.3 Path Protection in Ring Networks 322 16.3.2.4 OMS Link Protection-OMS-SPRing (Optical Multiplex Section-Shared Protection Ring) 322 16.3.2.5 Ring Loopback 323 16.3.2.6 Current Restoration Techniques 325 16.4 Energy Efficiency of Optical Switching Technology 326 16.5 Signal Quality Monitoring Techniques 327 16.6 Challenges and Recent Research Trends 328 16.7 Conclusion 330 Bibliography 330 17 Optical Switching for High-Performance Computing 335Rajendra Prasath, Bheemappa Halavar, and Odelu Vanga 17.1 Introduction 335 17.2 Optical Switching 336 17.2.1 Basics of Optical Switching 336 17.2.2 Types of Optical Switching 337 17.2.2.1 Optical Packet Switching 337 17.2.2.2 Circuit Switching 338 17.3 Communication vs Computation 338 17.4 Path Reservation Algorithms 338 17.5 High-Performance Optical Switching and Routing 339 17.5.1 HPC Interconnection Challenges 339 17.5.2 Challenges in the Design of Optical Interconnection Network 340 17.6 Optical Switching Schemes for HPC Applications 340 17.6.1 Routing Scheme (Avoid Packet Loss, Contention, etc.) 341 17.6.1.1 Buffering Schemes 341 17.7 Security Issues in Optical Switching 342 17.7.1 Network Vulnerabilities 342 17.7.1.1 Eavesdropping 342 17.7.2 Jamming Attacks (or Types of Attacks) 343 17.8 Optical Switching – Interesting Topics 344 17.9 Conclusion 344 Bibliography 344 18 Software for Optical Network Modelling 347Devlina Adhikari 18.1 Optical Networks 347 18.1.1 First Generation of Optical Networks 347 18.1.2 Second Generation of Optical Networks 348 18.1.2.1 Passive Optical Network 349 18.1.2.2 Elastic Optical Network 349 18.1.2.3 Cognitive Optical Network 349 18.1.2.4 Optical Neural Network 350 18.2 Simulation Tools for Planning of Optical Network 350 18.2.1 Network Simulators 350 18.2.1.1 NS-2 350 18.2.1.2 NS-3 351 18.2.1.3 OMNeT++ 351 18.2.1.4 OPNET 352 18.2.2 Physical Layer Simulation 352 18.3 New Technologies 353 18.3.1 Space Division Multiplexing (SDM) 353 18.3.2 Software-Defined Networking (SDN) 353 18.3.3 Artificial Intelligence/Machine Learning (AI/ML) 353 Bibliography 353 Index 359

Comprehensive coverage of optical switching technologies and their applications in optical networks Optical Switching: Device Technology and Applications in Networks delivers an accessible exploration of the evolution of optical networks with clear explanations of the current state-of-the-art in the field and modern challenges in the development of Internet-of-Things devices. A variety of optical switches—including MEMS-based, magneto, photonic, and SOA-based—are discussed, as is the application of optical switches in networks. The book is written in a tutorial style, easily understood by both undergraduate and graduate students. It describes the fundamentals and recent developments in optical switch networks and examines the architectural and design challenges faced by those who design and construct emerging optical switch networks, as well as how to overcome those challenges. The book offers ways to assess and analyze systems and applications, comparing a variety of approaches available to the reader. It also provides: A thorough introduction to switch characterization, including optical, electro optical, thermo optical, magneto optical, and acoustic-optic switchesComprehensive explorations of MEMS-based, SOA-based, liquid crystal, photonic crystal, and optical electrical optical (OEO) switchesPractical discussions of quantum optical switches, as well as nonlinear optical switchesIn-depth examinations of the application of optical switches in networks, including switch fabric control and optical switching for high-performance computing Perfect for researchers and professionals in the fields of telecommunications, Internet of Things, and optoelectronics, Optical Switching: Device Technology and Applications in Networks will also earn a place in the libraries of advanced undergraduate and graduate students studying optical networks, optical communications, and sensor applications.