Specialty Optical Fibers Handbook (eBook)

Cover 1
Copyright Page 5
Dedication 6
Contents 8
Editors 24
List of Contributors 26
Preface 38
Chapter 1: Specialty Optical Fiber Market Overview 44
1.1 Market Overview 44
1.1.1 Production Versus Consumption 44
1.1.2 Rapidly Growing Need to Use Fiber Optic Sensors 45
1.1.3 Weapon System Development 46
1.1.4 100–1000 X Improvements in Performance 46
1.1.5 High Cost of Functionality 47
1.1.6 Multiple Features in the Same Specialty Fibers 47
1.2 Specialty Optical Fibers: A Few Selected Examples 47
1.2.1 Fluoride Fiber 47
1.2.2 Tellurite Fiber 48
1.2.3 Bismuth-Doped Fiber 48
1.2.4 Polarizing Fiber 49
1.2.5 Photonic Crystal Fiber„Holey Fibers 50
1.2.6 Dispersion-Compensating Fiber 51
1.2.7 High-Index Fiber 54
1.2.8 Polarization-Maintaining Fiber 54
1.2.9 Photosensitive Fiber 56
1.2.10 Erbium-Doped Fiber 56
1.3 Conclusions 60
Chapter 2: Light-Guiding Fundamentals and Fiber Design 62
2.1 Introduction 62
2.2 Physical Structure of a Telecommunications Optical Fiber 63
2.3 Linear Lightwave Propagation in an Optical Fiber 63
2.3.1 Electromagnetic Preliminaries 63
2.3.2 Intuition from the Slab Waveguide 65
2.3.3 Optical Fiber: A Cylindrical Waveguide 67
2.3.4 The Linearly Polarized Mode Set LPlm 68
2.3.5 Finite Element Analysis for Waveguide Calculations 70
2.4 Working Definitions of Cutoff Wavelength 72
2.4.1 Introduction 72
2.4.2 Theoretical Cutoff Wavelength 72
2.4.3 Effective Cutoff Wavelengths 72
2.5 Impact of Profile Design on Macrobending Losses 75
2.5.1 The Depressed Cladding Fiber Design 75
2.5.2 Phenomenology of Macrobending Loss 77
2.6 Fiber Attenuation Loss 79
2.7 Origins of Chromatic Dispersion 81
2.7.1 Introduction 81
2.7.2 Material Dispersion 81
2.7.3 Waveguide Dispersion 85
2.8 Polarization Mode Dispersion 88
2.8.1 Overview 88
2.8.2 Background 89
2.8.3 Modeling and Simulation 91
2.8.4 Control of PMD in Fiber Manufacturing 92
2.8.5 Measurement of PMD 94
2.8.6 Fiber-to-Cable-to-Field PMD Mapping 96
2.9 Microbending Loss 98
2.9.1 Microbending 98
2.10 Fiber Nonlinearities 103
2.10.1 Overview 103
2.10.2 Background 104
References 108
Chapter 3: Overview of Materials and Fabrication Technologies 112
3.1 Double-Crucible Technique 112
3.2 Vapor-Deposition Techniques 113
3.3 Outside Vapor Deposition 114
3.4 Vertical Axial Deposition 116
3.5 Direct Nanoparticle Deposition 118
3.6 Modified Chemical Vapor Deposition 120
3.6.1 Chemical Equilibria: Dopant Incorporation 121
3.6.2 Purification from Hydroxyl Contamination 123
3.6.3 Thermophoresis 123
3.7 Plasma Chemical Vapor Deposition 125
3.8 Sol-Gel Processes 126
3.8.1 Alkoxide Sol-Gel Processing 126
3.8.2 Colloidal Sol-Gel Processing 127
3.9 Sol-Gel Microstructure Fiber Fabrication 129
3.10 Fiber Drawing 131
Acknowledgments 134
References 134
Chapter 4: Optical Fiber Coatings 138
4.1 Introduction 138
4.2 Early History of Coatings for Optical Fiber 139
4.3 Evolution of Optical Fibers and Protective Coatings 140
4.3.1 Coating Contributions to Microbending Minimization 140
4.3.2 Glass Fiber Fracture Mechanics and Coating Contributions to Fiber Strength Retention 142
4.3.3 Durability of Fiber Optic Coatings 143
4.4 Cabling of Optical Fibers 145
4.5 Specialty Coatings 146
4.6 Basics of Optical Fiber Chemistry 146
4.6.1 Oligomers 146
4.6.2 Monomers 148
4.6.3 Photoinitiators 148
4.6.4 Adhesion Promoters 148
4.6.5 Other Additives 149
4.7 Application of Coatings on the Draw Tower 151
4.7.1 Coating Cure Speed Measurement Techniques 153
4.7.2 Cured Properties of Coatings on Fiber 156
4.7.3 Test Methods for UV-Curable Liquids and UV-Cured Films 158
4.7.4 Coating Adhesion 160
4.8 Summary 160
Acknowledgments 161
References 161
Chapter 5: Single-Mode Fibers for Communications 166
5.1 Introduction 166
5.2 System Impairments Influencing Fiber Design 167
5.2.1 Limitations from Optical Signal-to-Noise Ratio 167
5.2.2 Limitations from Intersymbol Interference 168
5.2.3 Limitations from Nonlinearity 169
5.2.4 Limitations from Amplifier Technology 170
5.2.5 Can Fiber Design Be Used to Optimize a Transmission System? 170
5.3 Overview of ITU Standards Fiber Categories 172
5.4 Optical Fibers for Reduced Attenuation 175
5.4.1 Pure Silica Core Fiber 176
5.4.2 Zero Water Peak Fiber 176
5.5 Optical Fiber Design Principles for Wideband and High Bit Rate Transmission 184
5.5.1 Precise Dispersion Compensation 185
5.5.2 Dispersion Compensation Fiber Technology 185
5.5.3 Full-Band Dispersion Compensation 186
5.5.4 Requirement for Low Residual Dispersion 187
5.5.5 Factors Affecting Nonlinearity 188
5.5.6 Impairments Affecting Raman Amplification 190
5.5.7 Systems Implications of Tx Fiber PMD 190
5.5.8 Summary of Design Principles 191
5.6 Design of Nonzero Dispersion Fibers 191
5.6.1 Fiber Transmission Parameter Tradeoffs 192
5.6.2 Realizability, Manufacturability, and Scalability 193
5.6.3 Low-Dispersion NZDFs 195
5.6.4 Medium-Dispersion NZDFs 198
5.7 A New Paradigm in Transmission Line Design 201
References 202
Chapter 6: Specialty Single-Mode Fibers 208
6.1 Introduction 208
6.2 Macrohole Fiber 209
6.2.1 Microfluidic Devices 211
6.3 Fibers with Internal Electrodes 212
6.3.1 Electrodes 213
6.3.2 Applications 216
6.4 Multicore Fibers and Components 218
6.4.1 Coupled Cores 219
6.4.2 Uncoupled Cores 223
6.4.3 Manufacturing Multicore Fibers 225
6.5 Fibers for High-Temperature–Resistant Gratings 228
6.6 Summary 231
References 231
Chapter 7: Rare Earth-Doped Fibers 238
7.1 Introduction 238
7.2 Motivation 239
7.3 Host Glasses for Rare Earth Ions 241
7.4 Fabrication of Rare Earth-Doped Fibers 243
7.4.1 Overview of Optical Fiber Fabrication 243
7.4.2 Incorporation of Rare Earth Elements 245
7.4.3 Summary of Rare Earth-Doped Fabrication Techniques 253
7.5 Erbium-Doped Fiber 253
7.5.1 Principles of Operation 254
7.5.2 Fiber Design Issues 256
7.5.3 Fiber Composition Issues 259
7.5.4 Short Wavelength Amplifiers 262
7.6 The Co-Doped Er/Yb System 265
7.7 Double-Clad Fiber 266
7.7.1 Limitations of Fiber Lasers 269
7.7.2 Methods to Improve Performance 270
7.8 Conclusion 280
References 280
Chapter 8: Polarization Maintaining Fibers 286
8.1 What is a Polarization Maintaining Fiber? 286
8.2 Why Use PM Fibers?„Applications 287
8.2.1 Interferometry 287
8.2.2 The Fiber Optic Gyroscope 288
8.2.3 Coherent Communications 288
8.2.4 Integrated Optics 289
8.2.5 Laser Doppler Anemometry and Velocimetry 290
8.2.6 EDFA Pump Combiners, Reflection-Suppression Schemes, Current Sensing, and Optical Coherence Tomography 292
8.3 How Do PM Fibers Work? 292
8.4 PM Fiber Types: Stress and Form Birefringent 293
8.4.1 Stress-Birefringent Fibers: Bowtie, PANDA, and Elliptical Jacket 293
8.4.2 Elliptical Core, Form-Birefringent Fiber 296
8.4.3 Microstructure (‘‘Holey’’) Fibers 297
8.4.4 Polarizing Fiber 297
8.5 PM Fiber Fabrication Methods 299
8.5.1 Bowtie Fibers 299
8.5.2 PANDA Fiber 301
8.5.3 Elliptical Jacket Fiber 301
8.5.4 Elliptical Core, Form-Birefringent Fiber 303
8.5.5 Microstructure (‘‘Holey’’) Fibers 304
8.6 Key Performance Parameters 305
8.6.1 Attenuation (alpha) 305
8.6.2 Numerical Aperture (NA) 306
8.6.3 Is There a Connection Between Polarization Maintenance and Attenuation? 307
8.6.4 Cutoff Wavelength (lamdac) 307
8.6.5 Mode-Field Diameter (MFD) 308
8.6.6 Beat Length (Lp) 310
8.6.7 Extinction Ratio (ER) 312
8.6.8 H-Parameter 313
8.6.9 Effect of Test Conditions and Environment on Polarization Maintaining Performance 313
8.7 Mechanical and Lifetime Properties 316
8.7.1 Strength Paradox I: Fragile Preforms Make Exceptionally Strong Fibers 316
8.7.2 Strength Paradox II: Thin Fibers Can Be Stronger Than Thicker Ones 318
References 319
Chapter 9: Photosensitive Fibers 322
9.1 Introduction 322
9.2 Design and Fabrication 324
9.3 Standard Numerical Aperture Fibers 325
9.3.1 Standard Single-Mode Fibers 326
9.3.2 Boron-Doped Germano-Silicate Fibers 326
9.3.3 Antimony-Doped Fibers 329
9.3.4 Tin-Doped Fibers 330
9.4 High Numerical Aperture Fibers 330
9.4.1 Heavily Ge-Doped Silica Optical Fibers 331
9.4.2 Tin-Doped Germano-Silicate Fibers 332
9.4.3 Indium-Doped Germano-Silicate Fibers 333
9.5 Cladding Mode Suppression 334
9.6 Rare Earth-Doped Photosensitive Fibers 336
9.6.1 Germano-Alumino-Silicate Glass Host Core 337
9.6.2 Confined Core 340
9.6.3 Photosensitive-Clad 343
9.6.4 Confined Core and Photosensitive Clad 343
9.6.5 Antimony-Doped Alumino-Silicate 344
9.7 Polarization Maintaining 345
9.8 Other Photosensitive Fiber Types 346
9.8.1 Polymer Optical Fibers 347
9.8.2 Fluoride Glass 351
9.8.3 Heavily P-Doped Silica Fibers 351
9.9 Conclusions 352
Acknowledgments 353
References 353
Chapter 10: Hollow-Core Fibers 358
10.1 Introduction 358
10.1.1 Wave-Guiding by Total Internal Reflection 359
10.1.2 Wave-Guiding by Reflection Off a Conducting Boundary 360
10.1.3 Wave-Guiding by Photonic Band-Gaps 361
10.2 Light Transmission in Hollow-Core Fiber 363
10.2.1 Hollow Metal Waveguides 366
10.2.2 Wave-Guiding in Bragg and OmniGuide Fibers 367
10.2.3 Loss Mechanisms in OmniGuide Fibers 370
10.2.4 Wave-Guiding in 2D Photonic-Crystal Fiber 384
10.3 Applications of Hollow-Core Fibers 390
10.3.1 Hollow-Core Fibers for Medical Applications 390
10.3.2 Potential Telecom Applications 392
10.3.3 Hollow-Core Fibers as Gas Cells 393
10.3.4 Applications of Hollow-Core Fibers for Remote Sensing 394
10.3.5 Industrial Applications 394
10.4 Hollow-Core Fiber Manufacturing 395
10.4.1 OmniGuide Fiber Manufacturing 395
10.4.2 Techniques Used in the Manufacture of Other Hollow-Core Fibers 398
10.5 Conclusions 400
References 400
Chapter 11: Silica Nanofibers and Subwavelength-Diameter Fibers 404
11.1 Nanofiber at a Glance 404
11.2 Introduction 404
11.3 Modeling of Single-Mode Wave-Guiding Properties of Silica Nanofibers 405
11.3.1 Basic Model 406
11.3.2 Power Distribution: Fraction of Power Inside the Core and Effective Diameter 410
11.3.3 Group Velocity and Waveguide Dispersion 415
11.4 Fabrication and Microscopic Characterization of Silica Nanofibers 417
11.4.1 Two-Step Taper Drawing of Silica Nanofibers 418
11.4.2 Electron Microscope Study of Silica Nanofibers 420
11.5 Properties of Silica Nanofibers 424
11.5.1 Micromanipulation and Mechanical Properties 424
11.5.2 Wave-Guiding and Optical Loss 428
11.6 Applications and Potential Uses of Silica Nanofibers 431
11.6.1 Microscale and Nanoscale Photonic Components 432
11.6.2 Nanofiber Optical Sensors 437
11.6.3 Additional Applications 439
References 439
Chapter 12: Chiral Fibers 444
12.1 Introduction 444
12.2 Three Types of Chiral Gratings 445
12.3 Chiral Short-Period Grating: In-Fiber Analog of CLC 449
12.3.1 Fabrication Challenges 449
12.3.2 Analogy to 1D Chiral Planar Structure 449
12.3.3 Comparison of 1D Chiral to 1D Isotropic Layered Structures 450
12.3.4 Microwave Experiments 454
12.3.5 Optical Measurements 457
12.4 Chiral Intermediate-Period Grating 458
12.4.1 Symmetry of CIPG Structures 458
12.4.2 Microwave Experiments 458
12.4.3 Optical Measurements 459
12.4.4 Synchronization of Optical Polarization Conversion and Scattering 459
12.5 Chiral Long-Period Grating 466
12.5.1 Optical Measurements 466
12.6 Conclusion 469
Acknowledgments 469
References 469
Chapter 13: Mid-IR and Infrared Fibers 472
13.1 Introduction 472
13.2 Halide and Heavy Metal Oxide Glass Fiber Optics 476
13.2.1 Fluoride Glass Fibers 477
13.2.2 Germanate Glass Fibers 479
13.2.3 Chalcogenide Glass Fibers 480
13.3 Crystalline Fibers 483
13.4 Polycrystalline (PC) Fibers 484
13.5 Single-Crystal (SC) Fibers 486
13.6 Hollow-Core Waveguides 488
13.6.1 Hollow Metal and Plastic Waveguides 489
13.6.2 Hollow Glass Waveguides 489
13.7 Summary 493
References 493
Chapter 14: Hermetic Optical Fibers: Carbon-Coated Fibers 496
14.1 Introduction 496
14.2 History 498
14.3 Deposition of Carbon Coatings on Fibers 503
14.4 Fatigue Properties of Carbon-Coated Fibers 505
14.5 Hydrogen Losses in Optical Fibers 509
14.5.1 Hydrogen-Induced Losses in Nonhermetic Fibers 509
14.5.2 Hydrogen Losses in Carbon-Coated Hermetic Fibers 511
14.5.3 Testing of Hermetic Fibers in Hydrogen 512
14.5.4 Diffusion of Hydrogen in Hermetic Fibers 515
14.5.5 Effects of Glass Composition on Hermetic Fiber Behavior 520
14.6 Use and Handling of Carbon-Coated Hermetic Fibers 522
14.6.1 Fiber Strength 522
14.6.2 Fiber Handling 522
14.6.3 Fiber Stripping, Cleaving, and Connectorization 523
14.6.4 Fusion Splicing 523
14.6.5 Fiber Color 524
14.7 Specifying Carbon-Coated Fibers 524
14.8 Applications for Carbon-Coated Hermetic Fibers 528
14.8.1 Fibers in Underwater Cables 528
14.8.2 Amplifier Fibers 529
14.8.3 Avionics 529
14.8.4 Geophysical Sensors 529
14.9 Conclusion 530
References 531
Chapter 15: Metal-Coated Fibers 534
15.1 Introduction 534
15.2 Freezing Technique 536
15.3 Strength and Reliability 543
15.4 Degradation at High Temperature 548
15.5 Optical Properties of Metal-Coated Fibers 549
15.6 Summary 553
References 553
Chapter 16: Elliptical Core and D-Shape Fibers 556
16.1 Overview 556
16.1.1 Elliptical Core Optical Fiber 556
16.1.2 D-Shape Elliptical Core Fiber and Variations with Assessable Regions 557
16.2 Manufacturing of Elliptical Core and D-Shape Fibers 558
16.3 Elliptical Core Fibers: Characteristics and Properties 560
16.3.1 Birefringence 562
16.3.2 Polarization Holding 563
16.3.3 Ellipticity and Higher Order Modes 563
16.4 D-Shape Fibers: Characteristics and Properties 564
16.4.1 Accessing the Optical Fields: Fiber Etching 565
16.4.2 Wet Etching of Silicon Dioxide–Based Cladding and Germanosilicate Core 566
16.4.3 Standard Etching (Etch to Reach Evanescent Field) 567
16.4.4 Exposing the Core 569
16.4.5 Partial and Full Core Removal 571
16.5 D-Shape Fiber Components 571
16.5.1 Couplers 572
16.5.2 Loop Mirrors 573
16.5.3 Polarizers 573
16.5.4 Butt Coupling to Active Devices 574
16.5.5 Coupling to Integrated Optics 577
16.6 Splicing 578
16.6.1 D-Shape to D-Shape Fiber Splicing 578
16.6.2 D-Shape to Circular Clad Fiber Splicing 578
16.7 In-Fiber Devices 579
16.7.1 Electro-Optic Overlay Intensity Modulators 581
16.7.2 Replaced Cladding Phase Modulators 582
16.7.3 Partial and Full Core-Replaced Devices 584
16.7.4 Fiber Bragg Grating Devices 586
16.7.5 Variable Attenuators 588
16.7.6 Optical Absorption Monitoring 590
16.7.7 Intrinsic Fiber Sensors 591
16.7.8 D-Shape Fiber Opto-Electronic Devices 595
16.8 Rare Earth-Doped Elliptical Core Fiber 596
References 597
Chapter 17: Multimode, Large-Core, and Plastic Clad (PCS) Fibers 606
17.1 Introduction 606
17.2 Large-Core Silica/Silica (All-Silica) Fiber 608
17.3 High NA and Low NA Silica/Silica Fibers 611
17.4 Plastic and Hard Polymer Clad Silica Fibers 615
17.4.1 Plastic Clad Silica Fibers 615
17.4.2 Hard Polymer Clad Silica 615
17.5 Silica Fibers with Nano-Porous Cladding/Coating 617
17.6 Unlimited Application Potential 618
References 620
Chapter 18: Tapered Fibers and Specialty Fiber Microcomponents 622
18.1 Introduction 622
18.2 Tapers 625
18.2.1 Design of a Fiber Taper 626
18.3 Lenses 630
18.4 Diffusers 633
18.5 Side-Fire and Angled Ends 635
18.6 Optical Detection Windows for Microfluidic Flow Cells 636
Acknowledgments 640
References 640
Chapter 19: Liquid-Core Optical Fibers 642
19.1 Introduction 642
19.2 Propagation of Light in Liquid-Core Fibers: Modal Features, Dispersion, and Polarization Effects 643
19.3 Fabrication and Characterization Methods 645
19.4 Applications 648
19.4.1 Waveguides for Special Spectral Regions and Optical Chemical Analysis 648
19.4.2 Fiber Sensors 650
19.4.3 Nonlinear Optical Effects 652
19.4.4 Medical Applications 653
19.4.5 Special Waveguide Structures and Devices with Liquid Cores 655
19.5 Conclusions 656
References 657
Chapter 20: Polymer Optical Fibers 660
20.1 Introduction 660
20.2 POF Basics 660
20.2.1 Materials for POF 661
20.2.2 Light Propagation Effects in POF 663
20.2.3 Bandwidth of POF 665
20.3 Types of POF 665
20.4 POF Standards 675
20.5 POF Transmission Systems 676
20.5.1 SI-PMMA POF 676
20.5.2 PMMA-GI POF 677
20.5.3 PF-GI POF 677
20.6 Applications of POF 679
20.6.1 POF in Automobile Networks 679
20.6.2 POF Sensors 681
20.6.3 POF in Home Networks 683
20.7 POF Fabrication Methods 684
20.7.1 SI POF: Preform and Extrusion Method 685
20.7.2 Production of Graded-Index Profiles 687
20.7.3 Interfacial Gel Polymerization Technique 687
20.7.4 GI POF Extrusion 690
References 690
Chapter 21: Sapphire Optical Fibers 694
21.1 The Growth of Sapphire Fiber 695
21.2 Optical and Mechanical Characteristics of Single-Crystal Sapphire Fiber 699
21.3 Cladding and Coating of Sapphire Fibers 703
21.4 Applications of Sapphire Fibers 706
21.4.1 Optical Fiber Sensors 706
21.4.2 Medical Applications 710
21.5 Appendix: Material Properties of Al2O3 711
References 712
Chapter 22: Optical Fibers for Industrial Laser Applications 714
22.1 Fiber Lasers and Amplifiers: An Introduction 714
22.2 Cladding Pumped Fibers 715
22.3 Large-Mode-Area Ytterbium-Doped Fibers: The Power Revolution 716
22.4 Polarization-Maintaining LMA DCF 722
22.5 Fiber Lasers: State of the Art 729
22.6 Large-Mode-Area Eye-Safe Fibers 731
22.7 Conclusions 738
References 739
Chapter 23: Optical Fibers for Biomedical Applications 742
23.1 Introduction 742
23.2 Medical Laser Arms 743
23.3 Transendoscopic Surgical Application 746
23.3.1 Clinical Tests 748
23.4 Absorption Spectroscopy 751
23.4.1 Introduction 751
23.4.2 Medical Applications of Absorption Spectroscopy 752
23.5 Evanescent Wave Spectroscopy 754
23.5.1 Introduction 754
23.5.2 Experimental Setups 755
23.5.3 Chemical Sensing 757
23.5.4 Biochemical Sensing 758
23.6 Fiber Optic Thermal Sensing 760
23.6.1 Fiber Optic Thermal Sensor 761
23.6.2 Optical Fiber Radiometry 763
23.7 Thermal Imaging 765
23.7.1 Infrared Imaging and Tomography in Minimally Invasive Procedures 768
References 770
Chapter 24: Mechanical Strength and Reliability of Glass Fibers 778
24.1 Introduction 778
24.2 Review of Glass Properties 779
24.2.1 Noncrystallinity, the Glass Transition (Tg), and Relaxation Processes 779
24.2.2 Brittleness, Hardness, and Cracking 781
24.2.3 Composition Effects 783
24.3 Mechanical Properties 787
24.3.1 Strength 787
24.3.2 Fatigue 799
24.3.3 Aging 801
24.3.4 Nonsilicate Glasses 803
24.3.5 Photonic Crystal or ‘‘Holey Fibers’’ 806
24.4 Coatings 808
24.4.1 General Comments and Polymer Coatings 808
24.4.2 Metal Coatings 808
24.4.3 Inorganic Coatings 808
24.5 Handling and Post-Draw Processing 810
24.5.1 Fiber Stripping 810
24.5.2 Fiber Cleaving 811
24.5.3 Splicing 813
24.5.4 Polishing 815
24.5.5 Soldering/Pigtails 815
24.5.6 Recovery of Handling Damage: Etching 816
24.6 Fractography 817
24.7 Proof-Testing and Reliability 818
24.7.1 Minimum Strength Design 819
24.7.2 Failure Probability Design 819
Acknowledgments 821
References 821
Index 826