Specialty Optical Fibers HandbookMendez / Specialty Optical Fibers Handbook prelims Final Proof page i 31.10.2006 9:35pmThis page intentionally left blankSpecialty Optical FibersHandbookALEXIS MENDEZMCH Engineering, LLC, Alameda, CaliforniaT. F. MORSEPhotonics Center, Boston University, Boston, MassachusettsAMSTERDAM BOSTON HEIDELBERG LONDONNEW YORK OXFORD PARIS SAN DIEGOSAN FRANCISCO SINGAPORE SYDNEY TOKYOAcademic Press is an imprint of ElsevierMendez / Specialty Optical Fibers Handbook prelims Final Proof page iii 31.10.2006 9:35pmAcademic Press in an imprint of Elsevier30 Corporate Drive, Suite 400, Burlington, MA 01803, USA525 B Street, Suite 1900, San Diego, California 92101-4495, USA84 Theobalds Road, London WCIX 8RR, UKThis book is printed on acid-free paper.Copyright 2007, Elsevier Inc. All rights reserved.No part of this publication may be reproduced or transmitted in any form or by any means, electronicor mechanical, including photocopy, recording, or any information storage and retrieval system,without permission in writing from the publisher.Permissions may be sought directly from Elseviers Science & Technology Rights Department inOxford, UK: phone: (+44) 1865 843830, fax: (+44) 1865 853333, E-mail: permissions@elsevier.co.uk.You may also complete your request on-line via the Elsevier homepage (http://elsevier.com), byselecting Customer Support and then Obtaining Permissions.Library of Congress Cataloging-in Publication DataApplication SubmittedBritish Library Cataloguing in Publication DataA catalogue record for this book is available from the British LibraryISBN 13: 978-0-12-369406-5ISBN 10: 0-12-369406-XFor information on all Elsevier Academic Press publicationsvisit our Web site at www.books.elsevier.comPrinted in the United States of America06 07 08 09 10 9 8 7 6 5 4 3 2 1Mendez / Specialty Optical Fibers Handbook prelims Final Proof page iv 31.10.2006 9:35pmTo my wife Shivafor her unconditional love, support, and patienceA.M.Under the shade of your tresses,how softly slept my heart,intoxicated and lovely,so peaceful and so free . . . RUMITo Edelgardfor her patience, wisdom, and love.T.F.M.Mendez / Specialty Optical Fibers Handbook prelims Final Proof page v 31.10.2006 9:35pmThis page intentionally left blankContentsDedication vEditors xxiiiList of Contributors xxvPreface xxxvii1 Specialty Optical Fiber Market Overview 1Stephen Montgomery1.1 Market Overview 11.1.1 Production Versus Consumption 11.1.2 Rapidly Growing Need to Use Fiber Optic Sensors 21.1.3 Weapon System Development 31.1.4 1001000 Improvements in Performance 31.1.5 High Cost of Functionality 41.1.6 Multiple Features in the Same Specialty Fibers 41.2 Specialty Optical Fibers: A Few Selected Examples 41.2.1 Fluoride Fiber 41.2.2 Tellurite Fiber 51.2.3 Bismuth-Doped Fiber 51.2.4 Polarizing Fiber 61.2.5 Photonic Crystal FiberHoley Fibers 71.2.6 Dispersion-Compensating Fiber 81.2.7 High-Index Fiber 111.2.8 Polarization-Maintaining Fiber 111.2.9 Photosensitive Fiber 131.2.10 Erbium-Doped Fiber 131.3 Conclusions 172 Light-Guiding Fundamentals and Fiber Design 19Robert Lingle, Jr., David W. Peckham, Alan McCurdy,and Jinkee Kim2.1 Introduction 192.2 Physical Structure of a Telecommunications Optical Fiber 20Mendez / Specialty Optical Fibers Handbook prelims Final Proof page vii 31.10.2006 9:35pmvii2.3 Linear Lightwave Propagation in an Optical Fiber 202.3.1 Electromagnetic Preliminaries 202.3.2 Intuition from the Slab Waveguide 222.3.3 Optical Fiber: A Cylindrical Waveguide 242.3.4 The Linearly Polarized Mode Set LPlm 252.3.5 Finite Element Analysis for Waveguide Calculations 272.4 Working Definitions of Cutoff Wavelength 292.4.1 Introduction 292.4.2 Theoretical Cutoff Wavelength 292.4.3 Effective Cutoff Wavelengths 292.5 Impact of Profile Design on Macrobending Losses 322.5.1 The Depressed Cladding Fiber Design 322.5.2 Phenomenology of Macrobending Loss 342.6 Fiber Attenuation Loss 362.7 Origins of Chromatic Dispersion 382.7.1 Introduction 382.7.2 Material Dispersion 382.7.3 Waveguide Dispersion 422.8 Polarization Mode Dispersion 452.8.1 Overview 452.8.2 Background 462.8.3 Modeling and Simulation 482.8.4 Control of PMD in Fiber Manufacturing 492.8.5 Measurement of PMD 512.8.6 Fiber-to-Cable-to-Field PMD Mapping 532.9 Microbending Loss 552.9.1 Microbending 552.10 Fiber Nonlinearities 602.10.1 Overview 602.10.2 Background 61References 653 Overview of Materials and Fabrication Technologies 69John B. MacChesney, Ryan Bise, and Alexis Mendez3.1 Double-Crucible Technique 693.2 Vapor-Deposition Techniques 703.3 Outside Vapor Deposition 713.4 Vertical Axial Deposition 733.5 Direct Nanoparticle Deposition 75Mendez / Specialty Optical Fibers Handbook prelims Final Proof page viii 31.10.2006 9:35pmviii Contents3.6 Modified Chemical Vapor Deposition 773.6.1 Chemical Equilibria: Dopant Incorporation 783.6.2 Purification from Hydroxyl Contamination 803.6.3 Thermophoresis 803.7 Plasma Chemical Vapor Deposition 823.8 Sol-Gel Processes 833.8.1 Alkoxide Sol-Gel Processing 833.8.2 Colloidal Sol-Gel Processing 843.9 Sol-Gel Microstructure Fiber Fabrication 863.10 Fiber Drawing 88Acknowledgments 91References 914 Optical Fiber Coatings 95Steven R. Schmid and Anthony F. Toussaint4.1 Introduction 954.2 Early History of Coatings for Optical Fiber 964.3 Evolution of Optical Fibers and Protective Coatings 974.3.1 Coating Contributions to MicrobendingMinimization 974.3.2 Glass Fiber Fracture Mechanics and CoatingContributions to Fiber Strength Retention 994.3.3 Durability of Fiber Optic Coatings 1004.4 Cabling of Optical Fibers 1024.5 Specialty Coatings 1034.6 Basics of Optical Fiber Chemistry 1034.6.1 Oligomers 1034.6.2 Monomers 1054.6.3 Photoinitiators 1054.6.4 Adhesion Promoters 1054.6.5 Other Additives 1064.7 Application of Coatings on the Draw Tower 1084.7.1 Coating Cure Speed Measurement Techniques 1104.7.2 Cured Properties of Coatings on Fiber 1134.7.3 Test Methods for UV-Curable Liquidsand UV-Cured Films 1154.7.4 Coating Adhesion 1174.8 Summary 117Acknowledgments 118References 118Mendez / Specialty Optical Fibers Handbook prelims Final Proof page ix 31.10.2006 9:35pmContents ix5 Single-Mode Fibers for Communications 123Robert Lingle, Jr., David W. Peckham, Kai H. Chang,and Alan McCurdy5.1 Introduction 1235.2 System Impairments Influencing Fiber Design 1245.2.1 Limitations from Optical Signal-to-Noise Ratio 1245.2.2 Limitations from Intersymbol Interference 1255.2.3 Limitations from Nonlinearity 1265.2.4 Limitations from Amplifier Technology 1275.2.5 Can Fiber Design Be Used to Optimizea Transmission System? 1275.3 Overview of ITU Standards Fiber Categories 1295.4 Optical Fibers for Reduced Attenuation 1325.4.1 Pure Silica Core Fiber 1335.4.2 Zero Water Peak Fiber 1335.5 Optical Fiber Design Principles for Widebandand High Bit Rate Transmission 1415.5.1 Precise Dispersion Compensation 1425.5.2 Dispersion Compensation Fiber Technology 1425.5.3 Full-Band Dispersion Compensation 1435.5.4 Requirement for Low Residual Dispersion 1445.5.5 Factors Affecting Nonlinearity 1455.5.6 Impairments Affecting Raman Amplification 1475.5.7 Systems Implications of Tx Fiber PMD 1475.5.8 Summary of Design Principles 1485.6 Design of Nonzero Dispersion Fibers 1485.6.1 Fiber Transmission Parameter Tradeoffs 1495.6.2 Realizability, Manufacturability, and Scalability 1505.6.3 Low-Dispersion NZDFs 1525.6.4 Medium-Dispersion NZDFs 1555.7 A New Paradigm in Transmission Line Design 158References 1596 Specialty Single-Mode Fibers 165Lars-Erik Nilsson, Asa Claesson, Walter Margulis,and Pierre-Yves Fonjallaz6.1 Introduction 1656.2 Macrohole Fiber 1666.2.1 Microfluidic Devices 168Mendez / Specialty Optical Fibers Handbook prelims Final Proof page x 31.10.2006 9:35pmx Contents6.3 Fibers with Internal Electrodes 1696.3.1 Electrodes 1706.3.2 Applications 1736.4 Multicore Fibers and Components 1756.4.1 Coupled Cores 1766.4.2 Uncoupled Cores 1806.4.3 Manufacturing Multicore Fibers 1826.5 Fibers for High-TemperatureResistant Gratings 1856.6 Summary 188References 1887 Rare Earth-Doped Fibers 195David J. DiGiovanni, Roman Shubochkin, T. F. Morse,and Borut Lenardic7.1 Introduction 1957.2 Motivation 1967.3 Host Glasses for Rare Earth Ions 1987.4 Fabrication of Rare Earth-Doped Fibers 2007.4.1 Overview of Optical Fiber Fabrication 2007.4.2 Incorporation of Rare Earth Elements 2027.4.3 Summary of Rare Earth-DopedFabrication Techniques 2107.5 Erbium-Doped Fiber 2107.5.1 Principles of Operation 2117.5.2 Fiber Design Issues 2137.5.3 Fiber Composition Issues 2167.5.4 Short Wavelength Amplifiers 2197.6 The Co-Doped Er/Yb System 2227.7 Double-Clad Fiber 2237.7.1 Limitations of Fiber Lasers 2267.7.2 Methods to Improve Performance 2277.8 Conclusion 237References 2378 Polarization Maintaining Fibers 243Chris Emslie8.1 What is a Polarization Maintaining Fiber? 2438.2 Why Use PM Fibers?Applications 2448.2.1 Interferometry 2448.2.2 The Fiber Optic Gyroscope 245Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xi 31.10.2006 9:35pmContents xi8.2.3 Coherent Communications 2458.2.4 Integrated Optics 2468.2.5 Laser Doppler Anemometry and Velocimetry 2478.2.6 EDFA Pump Combiners, Reflection-SuppressionSchemes, Current Sensing, and Optical CoherenceTomography 2498.3 How Do PM Fibers Work? 2498.4 PM Fiber Types: Stress and Form Birefringent 2508.4.1 Stress-Birefringent Fibers: Bowtie, PANDA,and Elliptical Jacket 2508.4.2 Elliptical Core, Form-Birefringent Fiber 2538.4.3 Microstructure (Holey) Fibers 2548.4.4 Polarizing Fiber 2548.5 PM Fiber Fabrication Methods 2568.5.1 Bowtie Fibers 2568.5.2 PANDA Fiber 2588.5.3 Elliptical Jacket Fiber 2588.5.4 Elliptical Core, Form-Birefringent Fiber 2608.5.5 Microstructure (Holey) Fibers 2618.6 Key Performance Parameters 2628.6.1 Attenuation (a) 2628.6.2 Numerical Aperture (NA) 2638.6.3 Is There a Connection Between PolarizationMaintenance and Attenuation? 2648.6.4 Cutoff Wavelength (lc) 2648.6.5 Mode-Field Diameter (MFD) 2658.6.6 Beat Length (Lp) 2678.6.7 Extinction Ratio (ER) 2698.6.8 H-Parameter 2708.6.9 Effect of Test Conditions and Environmenton Polarization Maintaining Performance 2708.7 Mechanical and Lifetime Properties 2738.7.1 Strength Paradox I: Fragile Preforms MakeExceptionally Strong Fibers 2738.7.2 Strength Paradox II: Thin Fibers Can Be StrongerThan Thicker Ones 275References 276Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xii 31.10.2006 9:35pmxii Contents9 Photosensitive Fibers 279Andre Croteau and Anne Claire Jacob Poulin9.1 Introduction 2799.2 Design and Fabrication 2819.3 Standard Numerical Aperture Fibers 2829.3.1 Standard Single-Mode Fibers 2839.3.2 Boron-Doped Germano-Silicate Fibers 2839.3.3 Antimony-Doped Fibers 2869.3.4 Tin-Doped Fibers 2879.4 High Numerical Aperture 2879.4.1 Heavily Ge-Doped Silica Optical Fibers 2889.4.2 Tin-Doped Germano-Silicate Fibers 2899.4.3 Indium-Doped Germano-Silicate Fibers 2909.5 Cladding Mode Suppression 2919.6 Rare Earth-Doped Photosensitive Fibers 2939.6.1 Germano-Alumino-Silicate Glass Host Core 2949.6.2 Confined Core 2979.6.3 Photosensitive-Clad 3009.6.4 Confined Core and Photosensitive Clad 3009.6.5 Antimony-Doped Alumino-Silicate 3019.7 Polarization Maintaining 3029.8 Other Photosensitive Fiber Types 3039.8.1 Polymer Optical Fibers 3049.8.2 Fluoride Glass 3089.8.3 Heavily P-Doped Silica Fibers 3089.9 Conclusions 309Acknowledgments 310References 31010 Hollow-Core Fibers 315Steven A. Jacobs, Burak Temelkuran, Ori Weisberg, MihaiIbanescu, Steven G. Johnson, and Marin Soljacic10.1 Introduction 31510.1.1 Wave-Guiding by Total Internal Reflection 31610.1.2 Wave-Guiding by Reflection Off a ConductingBoundary 31710.1.3 Wave-Guiding by Photonic Band-Gaps 318Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xiii 31.10.2006 9:35pmContents xiii10.2 Light Transmission in Hollow-Core Fiber 32010.2.1 Hollow Metal Waveguides 32310.2.2 Wave-Guiding in Bragg and OmniGuide Fibers 32410.2.3 Loss Mechanisms in OmniGuide Fibers 32710.2.4 Wave-Guiding in 2D Photonic-Crystal Fiber 34110.3 Applications of Hollow-Core Fibers 34710.3.1 Hollow-Core Fibers for Medical Applications 34710.3.2 Potential Telecom Applications 34910.3.3 Hollow-Core Fibers as Gas Cells 35010.3.4 Applications of Hollow-Core Fibers forRemote Sensing 35110.3.5 Industrial Applications 35110.4 Hollow-Core Fiber Manufacturing 35210.4.1 OmniGuide Fiber Manufacturing 35210.4.2 Techniques Used in the Manufactureof Other Hollow-Core Fibers 35510.5 Conclusions 357References 35711 Silica Nanofibers and Subwavelength-Diameter Fibers 361Limin Tong and Eric Mazur11.1 Nanofiber at a Glance 36111.2 Introduction 36111.3 Modeling of Single-Mode Wave-GuidingProperties of Silica Nanofibers 36211.3.1 Basic Model 36311.3.2 Power Distribution: Fraction of PowerInside the Core and Effective Diameter 36711.3.3 Group Velocity and Waveguide Dispersion 37211.4 Fabrication and Microscopic Characterization of SilicaNanofibers 37411.4.1 Two-Step Taper Drawing of Silica Nanofibers 37511.4.2 Electron Microscope Study of Silica Nanofibers 37711.5 Properties of Silica Nanofibers 38111.5.1 Micromanipulation and Mechanical Properties 38111.5.2 Wave-Guiding and Optical Loss 38511.6 Applications and Potential Uses of Silica Nanofibers 38811.6.1 Microscale and Nanoscale Photonic Components 38911.6.2 Nanofiber Optical Sensors 39411.6.3 Additional Applications 396References 396Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xiv 31.10.2006 9:35pmxiv Contents12 Chiral Fibers 401Victor I. Kopp and Azriel Z. Genack12.1 Introduction 40112.2 Three Types of Chiral Gratings 40212.3 Chiral Short-Period Grating: In-Fiber Analog of CLC 40612.3.1 Fabrication Challenges 40612.3.2 Analogy to 1D Chiral Planar Structure 40612.3.3 Comparison of 1D Chiral to 1D IsotropicLayered Structures 40712.3.4 Microwave Experiments 41112.3.5 Optical Measurements 41412.4 Chiral Intermediate-Period Grating 41512.4.1 Symmetry of CIPG Structures 41512.4.2 Microwave Experiments 41512.4.3 Optical Measurements 41612.4.4 Synchronization of Optical PolarizationConversion and Scattering 41612.5 Chiral Long-Period Grating 42312.5.1 Optical Measurements 42312.6 Conclusion 426Acknowledgments 426References 42613 Mid-IR and Infrared Fibers 429James A. Harrington13.1 Introduction 42913.2 Halide and Heavy Metal Oxide Glass Fiber Optics 43313.2.1 Fluoride Glass Fibers 43413.2.2 Germanate Glass Fibers 43613.2.3 Chalcogenide Glass Fibers 43713.3 Crystalline Fibers 44013.4 Polycrystalline (PC) Fibers 44113.5 Single-Crystal (SC) Fibers 44313.6 Hollow-Core Waveguides 44513.6.1 Hollow Metal and Plastic Waveguides 44613.6.2 Hollow Glass Waveguides 44613.7 Summary 450References 450Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xv 31.10.2006 9:35pmContents xv14 Hermetic Optical Fibers: Carbon-Coated Fibers 453Paul J. Lemaire and Eric A. Lindholm14.1 Introduction 45314.2 History 45514.3 Deposition of Carbon Coatings on Fibers 46014.4 Fatigue Properties of Carbon-Coated Fibers 46214.5 Hydrogen Losses in Optical Fibers 46614.5.1 Hydrogen-Induced Losses in Nonhermetic Fibers 46614.5.2 Hydrogen Losses in Carbon-CoatedHermetic Fibers 46814.5.3 Testing of Hermetic Fibers in Hydrogen 46914.5.4 Diffusion of Hydrogen in Hermetic Fibers 47214.5.5 Effects of Glass Composition on Hermetic FiberBehavior 47714.6 Use and Handling of Carbon-Coated Hermetic Fibers 47914.6.1 Fiber Strength 47914.6.2 Fiber Handling 47914.6.3 Fiber Stripping, Cleaving, and Connectorization 48014.6.4 Fusion Splicing 48014.6.5 Fiber Color 48114.7 Specifying Carbon-Coated Fibers 48114.8 Applications for Carbon-Coated Hermetic Fibers 48514.8.1 Fibers in Underwater Cables 48514.8.2 Amplifier Fibers 48614.8.3 Avionics 48614.8.4 Geophysical Sensors 48614.9 Conclusion 487References 48815 Metal-Coated Fibers 491Vladimir A. Bogatyrev and Sergei Semjonov15.1 Introduction 49115.2 Freezing Technique 49315.3 Strength and Reliability 50015.4 Degradation at High Temperature 50515.5 Optical Properties of Metal-Coated Fibers 50615.6 Summary 510References 510Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xvi 31.10.2006 9:35pmxvi Contents16 Elliptical Core and D-Shape Fibers 513Thomas D. Monte, Liming Wang, and Richard Dyott16.1 Overview 51316.1.1 Elliptical Core Optical Fiber 51316.1.2 D-Shape Elliptical Core Fiber and Variations withAssessable Regions 51416.2 Manufacturing of Elliptical Core and D-Shape Fibers 51516.3 Elliptical Core Fibers: Characteristics and Properties 51716.3.1 Birefringence 51916.3.2 Polarization Holding 52016.3.3 Ellipticity and Higher Order Modes 52016.4 D-Shape Fibers: Characteristics and Properties 52116.4.1 Accessing the Optical Fields: Fiber Etching 52216.4.2 Wet Etching of Silicon DioxideBasedCladding and Germanosilicate Core 52316.4.3 Standard Etching (Etch to ReachEvanescent Field) 52416.4.4 Exposing the Core 52616.4.5 Partial and Full Core Removal 52816.5 D-Shape Fiber Components 52816.5.1 Couplers 52916.5.2 Loop Mirrors 53016.5.3 Polarizers 53016.5.4 Butt Coupling to Active Devices 53116.5.5 Coupling to Integrated Optics 53416.6 Splicing 53516.6.1 D-Shape to D-Shape Fiber Splicing 53516.6.2 D-Shape to Circular Clad Fiber Splicing 53516.7 In-Fiber Devices 53616.7.1 Electro-Optic Overlay Intensity Modulators 53816.7.2 Replaced Cladding Phase Modulators 53916.7.3 Partial and Full Core-Replaced Devices 54116.7.4 Fiber Bragg Grating Devices 54316.7.5 Variable Attenuators 54516.7.6 Optical Absorption Monitoring 54716.7.7 Intrinsic Fiber Sensors 54816.7.8 D-Shape Fiber Opto-Electronic Devices 55216.8 Rare Earth-Doped Elliptical Core Fiber 553References 554Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xvii 31.10.2006 9:35pmContents xvii17 Multimode, Large-Core, and Plastic Clad (PCS) Fibers 563Bolesh J. Skutnik and Cheryl A. Smith17.1 Introduction 56317.2 Large-Core Silica/Silica (All-Silica) Fiber 56517.3 High NA and Low NA Silica/Silica Fibers 56817.4 Plastic and Hard Polymer Clad Silica Fibers 57217.4.1 Plastic Clad Silica Fibers 57217.4.2 Hard Polymer Clad Silica 57217.5 Silica Fibers with Nano-Porous Cladding/Coating 57417.6 Unlimited Application Potential 575References 57718 Tapered Fibers and Specialty Fiber Microcomponents 579James P. Clarkin18.1 Introduction 57918.2 Tapers 58218.2.1 Design of a Fiber Taper 58318.3 Lenses 58718.4 Diffusers 59018.5 Side-Fire and Angled Ends 59218.6 Optical Detection Windows for Microfluidic Flow Cells 593Acknowledgments 597References 59719 Liquid-Core Optical Fibers 599Juan Hernandez-Cordero19.1 Introduction 59919.2 Propagation of Light in Liquid-Core Fibers:Modal Features, Dispersion, and Polarization Effects 60019.3 Fabrication and Characterization Methods 60219.4 Applications 60519.4.1 Waveguides for Special SpectralRegions and Optical Chemical Analysis 60519.4.2 Fiber Sensors 60719.4.3 Nonlinear Optical Effects 60919.4.4 Medical Applications 61019.4.5 Special Waveguide Structuresand Devices with Liquid Cores 61219.5 Conclusions 613References 614Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xviii 31.10.2006 9:35pmxviii Contents20 Polymer Optical Fibers 617Olaf Ziemann20.1 Introduction 61720.2 POF Basics 61720.2.1 Materials for POF 61820.2.2 Light Propagation Effects in POF 62020.2.3 Bandwidth of POF 62220.3 Types of POF 62220.4 POF Standards 63220.5 POF Transmission Systems 63320.5.1 SI-PMMA POF 63320.5.2 PMMA-GI POF 63420.5.3 PF-GI POF 63420.6 Applications of POF 63620.6.1 POF in Automobile Networks 63620.6.2 POF Sensors 63820.6.3 POF in Home Networks 64020.7 POF Fabrication Methods 64120.7.1 SI POF: Preform and Extrusion Method 64220.7.2 Production of Graded-Index Profiles 64420.7.3 Interfacial Gel Polymerization Technique 64420.7.4 GI POF Extrusion 647References 64721 Sapphire Optical Fibers 651J. Renee Pedrazzani21.1 The Growth of Sapphire Fiber 65221.2 Optical and Mechanical Characteristics of Single-CrystalSapphire Fiber 65621.3 Cladding and Coating of Sapphire Fibers 66021.4 Applications of Sapphire Fibers 66321.4.1 Optical Fiber Sensors 66321.4.2 Medical Applications 66721.5 Appendix: Material Properties of Al2O3 668References 66922 Optical Fibers for Industrial Laser Applications 671Adrian Carter, Kanishka Tankala, and Bryce Samson22.1 Fiber Lasers and Amplifiers: An Introduction 67122.2 Cladding Pumped Fibers 672Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xix 31.10.2006 9:35pmContents xix22.3 Large-Mode-Area Ytterbium-Doped Fibers: The PowerRevolution 67322.4 Polarization-Maintaining LMA DCF 67922.5 Fiber Lasers: State of the Art 68622.6 Large-Mode-Area Eye-Safe Fibers 68822.7 Conclusions 695References 69623 Optical Fibers for Biomedical Applications 699Moshe Ben-David and Israel Gannot23.1 Introduction 69923.2 Medical Laser Arms 70023.3 Transendoscopic Surgical Application 70323.3.1 Clinical Tests 70523.4 Absorption Spectroscopy 70823.4.1 Introduction 70823.4.2 Medical Applications of Absorption Spectroscopy 70923.5 Evanescent Wave Spectroscopy 71123.5.1 Introduction 71123.5.2 Experimental Setups 71223.5.3 Chemical Sensing 71423.5.4 Biochemical Sensing 71523.6 Fiber Optic Thermal Sensing 71723.6.1 Fiber Optic Thermal Sensor 71823.6.2 Optical Fiber Radiometry 72023.7 Thermal Imaging 72223.7.1 Infrared Imaging and Tomography in MinimallyInvasive Procedures 725References 72724 Mechanical Strength and Reliability of Glass Fibers 735Charles R. Kurkjian and M. John Matthewson24.1 Introduction 73524.2 Review of Glass Properties 73624.2.1 Noncrystallinity, the Glass Transition (Tg), andRelaxation Processes 73624.2.2 Brittleness, Hardness, and Cracking 73824.2.3 Composition Effects 740Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xx 31.10.2006 9:35pmxx Contents24.3 Mechanical Properties 74424.3.1 Strength 74424.3.2 Fatigue 75624.3.3 Aging 75824.3.4 Nonsilicate Glasses 76024.3.5 Photonic Crystal or Holey Fibers 76324.4 Coatings 76524.4.1 General Comments and Polymer Coatings 76524.4.2 Metal Coatings 76524.4.3 Inorganic Coatings 76524.5 Handling and Post-Draw Processing 76724.5.1 Fiber Stripping 76724.5.2 Fiber Cleaving 76824.5.3 Splicing 77024.5.4 Polishing 77224.5.5 Soldering/Pigtails 77224.5.6 Recovery of Handling Damage: Etching 77324.6 Fractography 77424.7 Proof-Testing and Reliability 77524.7.1 Minimum Strength Design 77624.7.2 Failure Probability Design 776Acknowledgments 778References 778Index 783Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxi 31.10.2006 9:35pmContents xxiThis page intentionally left blankEditorsAlexis Mendez Dr. Alexis Mendez is President and founder of MCH Engin-eering LLC, a consulting firm specializing in optical fiber sensing technology.Dr. Mendez has over 20 years of experience in optical fiber technology, sensors,and instrumentation. Prior to founding MCH, Dr. Mendez occupied variousmanagement positions within the optical communications industry in SiliconValley. He was the former Group Leader of the Fiber Optic Sensors Lab withinABB Corporate Research (USA), where he led research and development sensoractivities for oil and gas, electric utility, and industrial processing applications.He has developed fiber Bragg grating downhole pressure and temperature sen-sors, fiber optic high voltage and current sensors, and others. He has alsoconducted research to investigate hydrogen effects on fibers.Dr. Mendez has written over 45 technical publications, holds four US patentsand is the recipient of an R&D 100 award. He is also chairman of the nextInternational Optical Fiber Sensors Conference (OFS-18). Dr. Mendez holds aPhD degree in electrical engineering from Brown University.T. F. Morse T. F. Morse received a BA (english literature, 1953) and an MA(history, 1954) from Duke University. He was an International Institute ofEducation Fellow at Cologne University, Germany in 19541955 (history,political science). From 19561959, he was employed at Pratt and WhitneyAircraft, East Hartford, Connecticut, during which time he received an ScB(mechanical engineering) from the University of Hartford, and a MSc (mechan-ical engineering) from the Rensselaer Polytechnic Hartford Graduate Center.Attending graduate school at Northwestern University, he was awarded a PhD(mechanical engineering) in 1961. From 19611963, he was a Senior Scientist atARAP in Princeton, New Jersey where he worked on a variety of theoreticalfluid mechanical problems. As an Engineering Professor at Brown University,Providence, Rhode Island (19631999), he was the Director of the Laboratoryfor Lightwave Technology and in 19691970, was a Senior Fulbright ResearchProfessor at the Deutsche Versuchs-Anstalt fuer Luft u. Raumforschung. Since1999, he has been at Boston University as Professor of Electrical and ComputingEngineering and Director of the Laboratory for Lightwave Technology. He isthe author of over 120 papers and holds five patents. His research interests andareas of expertise are in fiber processing, photonic materials, fiber lasers, andfiber sensors.Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxiii 31.10.2006 9:35pmxxiiiThis page intentionally left blankList of ContributorsMoshe Ben-David Dr. Moshe Ben-David received his PhD degree in physicsfrom Tel-Aviv University, Tel-Aviv, Israel in 2003. He has over 10 years experi-ence in developing electro-optical systems for military, telecommunication, en-tertainment, and medical applications, currently with Glucon Medical. He is theauthor of over 20 papers, 4 book chapters, and 4 patents. His research fields are:optical fibers and waveguides, laser tissue interaction, optical diagnosticsmethods in medicine, and light propagation in tissue.Ryan Bise Dr. Ryan Bise is a member of the Technical Staff at OFS Labora-tories in Murray Hill, New Jersey, formerly the optical fiber research arm of BellLaboratories, Lucent Technologies. His research focus is on the fabrication anddesign of microstructured fibers. He received his undergraduate and graduatetraining in chemistry from UCLA and UC Berkeley, respectively.Vladimir A. Bogatyrev Vladimir A. Bogatyrev graduated from the MoscowPhysical Technological Institute in 1972. From 1972 to 1982, he investigatedhigh-power neodymium lasers in PN Lebedev Physical Institute RAS. Since1982, his research interests were moved to the technology of optical fibers andrelated topics (the fiber drawing process, properties of polymer and hermeticcoatings, strength and fatigue of optical fibers). He is currently a ResearchFellow of the Fiber Optics Research Center RAS, Moscow, Russia. His mainactivity is focused on metal-coated fibers (technology of fabrication and inves-tigation of their mechanical and optical properties).Adrian Carter Dr. Adrian Carter is the founder and CTO of Nufern. Prior tothat, he was an Assistant Professor at the Laboratory for Lightwave Technologyat Brown University. Dr. Carter was a Postdoctoral Fellow at the Optical FibreTechnology Center in Sydney, Australia where he focused on the design andfabrication of novel specialty optical fibers, having also been a Research Fellowat the Technische Universitaet Hamburg-Harburg, Germany. He received hisPhD in the Department of Physical and Theoretical Chemistry and his BSc inmathematics and chemistry from the University of Sydney, where he is currentlyalso an Honorary Research Associate.Kai H. Chang Kai H. Chang has been the Engineering Manager at HeraeusTenevo USA since 2005. From 1986 to 2005, he worked at Bell Laboratories ofMendez / Specialty Optical Fibers Handbook prelims Final Proof page xxv 31.10.2006 9:35pmxxvAT&T/Lucent Technologies/OFS in Norcross, Georgia, and he was the Tech-nical Manager of MCVD Technology and a Distinguished Inventor. Kai hasworked on optical loss mechanisms in silica fibers and was one of the pioneersthat developed zero-OH AllWave1fiber. Kai obtained his PhD in physics fromUniversity of Toronto in 1984 and worked at Caltech as a Research Fellow inphysics from 1984 to 1986.Asa Claesson Asa Claesson graduated with a MSc in materials science fromUppsala University, Sweden, in 1997 and has since been active in developingfiber based optical components, as well as optical specialty fibers. She has co-authored more than 20 scientific publications, 4 patents, and 2 book chapters.She is presently the manager of Acreo Fiberlab in Sweden.James P. Clarkin James P. Clarkin is the Vice President of BusinessDevelopment at Polymicro Technologies, LLC. Mr. Clarkin has 20 years experi-ence in the design, performance, and manufacture of all types of optical fibers.Prior to joining Polymicro in 1998, Jim spent 12 years at Ensign Bickford/Spectran Corporation as Engineering Manager and Product Line Manager.While at Spectran, Jim led the development and production of their specialtyoptical fiber and cable product lines. Jim has a BS in chemical engineering, anMS in materials science, and an MBA, all from Rensselaer Polytechnic Institute.Andre Croteau Andre Croteau received an MSc degree in physics from QueensUniversity in Kingston, Ontario, Canada in 1986. From 1986 to 1988, Andre wasa researcher at the fundamental research laboratory of NEC Corporationin Japan, where he worked on the development of electro-optic thin films. In1988, Andre joined INO as a researcher in the specialty optical fiber programwhere he became the manager in 1998. His main research activities includethe development of active rare earth-doped fibers, micro structured fibers,and photosensitive fibers. He has published over 20 papers and received 3patents.David J. DiGiovanni David J. DiGiovanni is President of OFS Laboratories,LLC, the central research organization of OFS. David began his career with apostdoctoral position in the Optical Fiber Research Department in Bell Labora-tories and has weathered the transition from AT&T to Lucent to OFS in what isessentially the same organization. He has worked on various phenomena relatedto optical fiber design and fabrication and has made notable contributions toerbium-doped optical fibers for amplifiers, high power amplifiers and lasers,Raman amplification, and optical components. David holds several degreesfrom Brown University, including a PhD in mechanical engineering. He is amember of IEEE and an OSA Fellow.Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxvi 31.10.2006 9:35pmxxvi List of ContributorsChris Emslie Dr. Chris Emslie is Managing Director of Fibercore Limited. Hebegan his career in optical fibers in 1982 at Cornings pilot manufacturing facilityin Wilmington, North Carolina. He received a PhD from the Optical FiberGroup at the University of Southampton (UK). His thesis focused on themanufacture of low-loss polymer fibers, under the guidance of Professors AlecGambling and David Payne. Dr. Emslie left Southampton in 1987 to take acommercial role at a fledgling optical components company, York VSOP, andtaking charge of its Specialty Fiber business in 1989. This business graduallyevolved into Fibercore Limited.Pierre-Yves Fonjallaz Pierre-Yves Fonjallaz obtained the MSc degree inphysical engineering and the PhD degree (fibre Bragg gratings) from the SwissFederal Institute of Technology in Lausanne in 1990 and 1995. After a postdoc-toral at KTH, he started to work at Acreo AB (Sweden) in 1996. He becamemanager of the Optical Fibre Components group (2000). He was appointeddirector of the Kista Photonics Research Centre (KPRC) in 2003, and as suchcoordinates the collaboration between Acreo and the Royal Institute of Tech-nology (KTH) in photonics. He has been organizing a number of workshops andconferences, such as ECOC in 2004.Israel Gannot Professor Israel Gannot received his PhD degree in biomedicalengineering from Tel-Aviv University, Tel-Aviv, Israel in 1994. Between 1994and 1997, he held a National Academy Sciences postdoctoral fellowship. Since1997, he has been a faculty member at Tel-Aviv University, and since 2005 he hasbeen a professor of biomedical engineering at George Washington University.Professor Gannot is a Fellow of the American Institute of Medical and Bio-logical Engineering. He is the author of over 100 papers, 6 book chapters, and 10patents. His research fields are: optical fibers and waveguides, laser tissue inter-action, optical diagnostics methods in medicine, and biomedical informatics.Azriel Z. Genack Azriel Genack is a Distinguished Professor of Physics atQueens College of CUNY, where he has been since 1984. He received his BAdegree from Columbia College and his PhD in physics from Columbia Univer-sity. Following his graduate studies, he was a Postdoctoral Research Associate atthe City College of CUNY and then at the IBM Research Laboratory in SanJose. He was a researcher at the Exxon Corporate Research Laboratories from1977 until 1984. He co-founded Chiral Photonics in 1999. His research centers onthe photonics of chiral structures and the statistics of propagation and localiza-tion of optical and microwave radiation in random media.James A. Harrington James A. Harrington is a Professor of Ceramic Scienceand Engineering at Rutgers University. Dr. Harrington has over 30 years ofresearch experience in IR materials and fibers and is the inventor of both theMendez / Specialty Optical Fibers Handbook prelims Final Proof page xxvii 31.10.2006 9:35pmList of Contributors xxviihollow sapphire and hollow glass waveguides. He is generally recognized as oneof the worlds leading experts in this continually evolving field. Prior to joiningthe Fiber Optic Materials Research Program at Rutgers University in 1989, hewas Director of Infrared Fiber Operations for Heraeus LaserSonics, and prior tothis role, he was the Program Manager for IR fiber optics at Hughes ResearchLaboratories in Malibu, California.Juan Hernandez-Cordero Dr. Juan Hernandez-Cordero received his BSc degreein electrical engineering from the National Autonomous University of Mexico(UNAM) in 1992. He was awarded a full scholarship to pursue graduate studiesat Brown University, where he earned a Masters (1996) and PhD degrees (1999)from the Division of Engineering. After a year as a Postdoctoral ResearchAssociate at the Laboratory for Lightwave Technology in Boston University,he joined the Materials Research Institute (IIM) of the UNAM, where he hasestablished the Fiber Lasers and Fiber Sensors Laboratory. His fields of interestinclude optical fiber sensors, fiber lasers, and fiber devices.Mihai Ibanescu Mihai Ibanescu received his BS and PhD degrees in physicsfrom the Massachusetts Institute of Technology in 2000 and 2005. From 2005 to2006, he was a Postdoctoral Associate in the research group of Professor JohnJoannopoulos at MIT. During 20002001, and since 2006, he worked withOmniGuide Inc., in Cambridge, Massachusetts. His main research interests arephotonic crystals, photonic band gap fibers, and hollow-core fiber applications.Anne Claire Jacob Poulin Anne Claire Jacob Poulin joined INO as a researcherin 2000 after a PhD degree in physics from the Center for Optics, Photonics, andLasers of Laval University, Quebec, Canada and a MSc degree in physics fromthe Centre de Physique Moleculaire Optique et Hertzienne, Bordeaux I Univer-sity, France. She first worked in the communication field with the fabrication ofpassive optical components with photosensitive fibers and the development ofoptical fiber amplifiers with specialty-doped fluoride fibers. Her current researchinterests are on the fabrication and application of photonics devices to sensorssystems in the agri-food and biomedical fields.Steven A. Jacobs Steven Jacobs is the Systems Engineering Group Leader atOmniGuide Inc., where he leads the development of new medical systems thatenable minimally invasive laser surgery based on OmniGuides photonic-band-gap fiber technology. Prior to that position, he was the Theory and SimulationsGroup Leader. He received his BS degree from MIT and his PhD degree fromthe University of Wisconsin, both in physics. Before joining OmniGuide in 2001,Dr. Jacobs was a Distinguished Member of Technical Staff at Bell Laboratories.His professional interests include computational electromagnetics and the use ofcomputational and statistical methods for yield and process improvement.Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxviii 31.10.2006 9:35pmxxviii List of ContributorsSteven G. Johnson Steven Johnson received his PhD in 2001 from the Depart-ment of Physics at MIT. He is currently an Assistant Professor of AppliedMathematics at MIT, and also consults for OmniGuide Inc. He has writtenseveral widely-used, free software packages, including the MPB package to solvefor photonic eigenmodes and the FFTW fast Fourier transform library (forwhich he received the 1999 J. H. Wilkinson Prize). In 2002, Kluwer publishedhis PhD thesis as a book, Photonic Crystals: The Road from Theory to Practice.His research interests include the development of new semi-analytical and nu-merical methods for electromagnetism in high-index-contrast systems.Jinkee Kim Jinkee Kim received BS and MS degrees in electrical engineeringfrom the Seoul National University and a PhD degree in electrical and computerengineering from the Georgia Institute of Technology. His doctoral research wason integrated optics, 100Gbit/s telecommunication, and digital signal processing.He worked at CREOL in Orlando as a Research Scientist, where his researchwas focused on photonic control systems for phased arrays. In 1996, he joinedBell Laboratories, Lucent Technologies (now OFS), and works in fiber opticsR&D. He has designed and commercialized new optical fibers and holds severalUS patents.Victor I. Kopp Victor Kopp is the Director of Research and Development atChiral Photonics, Inc. He received his PhD degree in laser physics from theVavilov Optical Institute, St. Petersburg, Russia in 1992. In 1999, working as aResearch Associate at Queens College of CUNY, he developed the scientificbasis for Chiral Photonics, Inc. with Azriel Genack and became a co-founder ofthe company. His research interests include wave propagation in periodic media,nonlinear optics, and photonic devices. He is the author and co-author of over 25papers, as well as over 20 US and international patents on photonic devices,lasers, and fiber gratings.Charles R. Kurkjian Dr. Kurkjian is currently a visiting scientist in the Mater-ials Science and Engineering Department at Rutgers University, Piscataway,New Jersey. He had previously worked at Bell Laboratories in Murray Hill,New Jersey for 35 years and at Telcordia (formerly Bellcore) in Morristown,New Jersey for five years before retiring and joining Rutgers in 1999. He hasworked in a number of areas of inorganic glass research and development.Currently, he is concentrating on the mechanical properties of such glasses, aswell as the strength and reliability of silica lightguide fibers.Paul J. Lemaire Paul J. Lemaire is a Senior Lead Engineer with GeneralDynamics Advanced Information Systems in Florham Park, New Jersey. Hehas held technical and management positions at OFS, Lucent Technologies, andBell Laboratories. His work has been in the areas of optical fiber fabrication,Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxix 31.10.2006 9:35pmList of Contributors xxixhermetic fibers, fiber design, fiber Bragg gratings, photosensitivity, fiber andcomponent reliability, hydrogen aging, and other topics pertaining to photonics,materials, and reliability. He has numerous publications, presentations, andpatents in these areas. He received both his BS and PhD degrees from theDepartment of Materials Science and Engineering at MIT.Borut Lenardic Borut Lenardic received a BSc degree in solid state physicsfrom the Faculty of Natural Sciences, University of Ljubljana in 1981 andstarted his work in fiber optics in 1986 as a Development Engineer in Iskra,Slovenia. Later he worked as a Process Specialist in Cabloptic, Switzerland andFotona, Slovenia. From 1996 to 2001, he worked as a consultant for NextromOy. In 2001 he founded Optacore, a company dedicated to development ofpreform and fiber fabrication process, based on furnace-supported CVD, inLjubljana, Slovenia. Since 2004, he has been developing technology and devicesfor fabrication of rare earth-doped fibers with emphasis on aerosol and hightemperature sublimation processes.Eric A. Lindholm Eric A. Lindholm received his BSci in ceramic engineeringand his BA in english from Rutgers University in 1991. He spent five years atSpectran Communication Fiber Technologies as a Fiber Draw Engineer beforebecoming a Fiber Development Engineer at OFS Specialty Photonics (formerlySpectran Specialty Optics) in 1996. Eric has since focused on the hermetic carbondeposition process, polymer materials, and fiber draw processes designed toenhance the durability of optical fibers used in adverse environment applica-tions, and characterization of the fibers. He has written and given severaltechnical presentations on related subjects at various conferences.Robert Lingle, Jr. Robert Lingle, Jr. completed his BS degree in physics fromthe University of Alabama, a PhD in chemical physics from the Louisiana StateUniversity, and held a postdoctoral fellowship at UC Berkeley in ultrafastphysical chemistry. He joined the Optical Fiber Division of Lucent Technologies,Bell Laboratories in 1997, where he remained through the transition to OFS. Hehas conducted research on ultrafast electronic and vibrational processes insolution and at interfaces, sol-gel materials, physics and chemistry for opticalmaterials, optical fiber design, and nonlinear impairments in optical transmis-sion. Dr. Lingle is Director of Fiber Design and Transmission Systems at OFS.John B. MacChesney JohnMacChesney is a retired Bell Labs Fellowand formermember of Lucents Photonics Materials Research Department. Dr. MacChesneyis best known for his invention of the modified chemical vapor deposition(MCVD) process, for which he received the National Academy of EngineeringsCharles Stark Draper Prize. He joined Bell Labs in 1959 and holds morethan 100 domestic and foreign patents. Dr. MacChesney was elected to theMendez / Specialty Optical Fibers Handbook prelims Final Proof page xxx 31.10.2006 9:35pmxxx List of ContributorsNational Academy of Engineering in 1985, and has received awards from theAmerican Ceramic Society, the IEEE, the American Physical Society, the Societyof Sigma Xi, and others. He holds a BA degree from Bowdoin College and a PhDfrom Pennsylvania State University.Walter Margulis Walter Margulis received his PhD from Imperial College,London in 1981. Presently, he works on the fabrication, characterization, andapplications of fiber components, design, and fabrication of special fibers foractive functions, poling of glass, photosensitivity, and applications of Bragggratings in optical fibers, optical amplifiers, and passive microwave components.He has co-authored ~185 papers/conference contributions, ~15 patent applica-tions and has supervised over 25 graduate students. He is a Senior Scientist atAcreo AB in Sweden, and a Guest Professor at the Royal Institute of Technologyin Stockholm.M. John Matthewson John Matthewson received his BA, MA, and PhDdegrees in physics from Cambridge University. He continued at Cambridgeconcurrently as the Goldsmiths Junior Research Fellow at Churchill Collegeand as a SRC Postdoctoral Fellow. He later worked at the Cambridge UniversityComputing Service, AT&T Bell Laboratories, and IBM Almaden ResearchCenter. He is now a Professor of Materials Science and Engineering at RutgersUniversity. His research group studies strength and fatigue of optical materialsand modeling of materials processing. He has published over 100 papers, manyof them concerning optical fiber reliability, and he has been editor or co-editor ofsix conference proceedings on the same topic.Eric Mazur Professor Eric Mazur holds a triple appointment as HarvardCollege Professor, Gordon McKay Professor of Applied Physics, and Professorof Physics at Harvard University. His area of interest is optical physics. Hereceived a PhD degree in experimental physics at the University of Leiden in theNetherlands. Dr. Mazur is author or co-author of 187 scientific publications andhas made important contributions to spectroscopy, light scattering, and studiesof electronic and structural events in solids that occur on the femtosecond timescale. In 1988, he was awarded a Presidential Young Investigator Award and is aFellow and Centennial Lecturer of the American Physical Society.Alan McCurdy Alan McCurdy graduated with degrees in chemical engin-eering (BS) and physics (BS) from Carnegie-Mellon University, and appliedphysics (PhD) from Yale University. He spent nine years on the faculty of theDepartment of Electrical Engineering at the University of Southern California.His telecommunications work began at Lucent Technologies, then Avaya, andmost recently OFS. He has done research on high power, electron-beam drivenmicrowave devices, transmission problems in copper-based enterprise networkMendez / Specialty Optical Fibers Handbook prelims Final Proof page xxxi 31.10.2006 9:35pmList of Contributors xxxisystems, and statistical and nonlinear problems in optical communications.Dr. McCurdy is currently a Distinguished Member of Technical Staff in theOptical Fiber Design Group at OFS.Thomas D. Monte Thomas D. Monte received a PhD degree in electricalengineering from the University of Illinois at Chicago in 1996. As PrincipalPhotonics Engineer at KVH Industries, Inc., he has been involved in the researchof elliptical core polarization maintaining optical fiber components and sensorassemblies. Between 1983 and 2000, Dr. Monte held various engineeringand research positions at Andrew Corporation developing fiber optic devices,microwave waveguide components, and antennas. He holds 11 US patentsand several international patents in the fields of microwave and fiber opticcomponents.Stephen Montgomery Stephen Montgomery is the President of ElectroniCast,a firm specializing in communication network products and services demandforecasting. Stephen is also the Director of the Fiber Optics Components groupand the Network Communication Products group at ElectroniCast. He has givennumerous presentations and published a number of articles on optical fibermarkets, technology, applications, and installations. He is a member of theEditorial Advisory Board of Lightwave magazine and the Advisory Board ofthe Gigabit Ethernet Conference (GEC). Stephen holds a BA and MBA inTechnology Management.Lars-Erik Nilsson Lars-Erik Nilsson graduated with a degree in chemistry fromthe Royal Institute of Technology, Stockholm in 1973, and has since been activewithin industry as well as academia with a main focus on development of opticalinstruments and components. Lars-Erik has been engaged in design and devel-opment of specialty optical fibers and fiber-based components for over 10 yearsand is presently heading the Optical Fiber Component group at Acreo AB inSweden. He has co-authored over 12 scientific publications and is the inventor/co-inventor of six patents.David W. Peckham David W. Peckham received BS and ME degreesin electrical engineering from the University of Florida. He started his career atthe Bell Labs Transmission Media Laboratory in 1982 working on optical fibermeasurement techniques. Since 1989, he has focused on the design, processdevelopment, and commercialization of optical fibers for high capacity trans-mission systems at Bell Labs, Lucent, and currently, OFS. He received the 2002OSA Engineering Excellence Award recognizing his contributions in the designand commercialization of fibers enabling high speed, wideband WDM networks.He is currently a Consulting Member of Technical Staff at OFS.Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxxii 31.10.2006 9:35pmxxxii List of ContributorsJ. Renee Pedrazzani J. Renee Pedrazzani is a PhD candidate at the Institute ofOptics of the University of Rochester, where she is engaged in semiconductordevice research at the Molecular Beam Epitaxy Laboratory. She received her BSand MS degrees in electrical engineering from the Virginia Polytechnic Instituteand State University, and conducted her MS research at the Fiber and Electro-Optic Research Center. Before beginning her doctoral studies, she worked withoptical fiber gratings at Lucent Technologies.Bryce Samson Dr. Samson is the Vice President of Business Development atNufern, having joined Nufern from Corning, where he served as Senior ResearchScientist in the areas of doped fibers, fiber amplifiers, and lasers. Prior to that, heworked as a Research Fellow at the University of Southampton, focusing onnovel fibers and fiber device physics. He received his PhD in physics from EssexUniversity in the UK and his BS degree in applied physics from Heriott-WattUniversity in Edinburgh, UK. He is an inventor on several patents in the amplifierand fiber laser field and has been published in scores of industry journals.Steven R. Schmid StevenR. Schmidis R&DManager for DSMDesotechs FiberOptic Materials Research business. He has also held positions in product man-agement, market development, and business management. He has 30 years experi-ence in the UV coatings industry. Steven earned a BS in chemistry (University ofIlliniois), an MS degree in chemistry (University of Houston), and an MBA (IIT).Steven has authored over a dozen papers, been awarded 10 patents, and madeseveral international presentations. He was a co-recipient of an IR100 Award in1987, and also a co-recipient of DSMs Special Inventor Award in 2001.Sergei Semjonov Sergei Semjonov graduated from the Moscow Physical Tech-nological Institute in 1982. In 1997, he received his PhD in Physics from GeneralPhysics Institute, RussianAcademy of Sciences, Moscow, Russia. He is currently aDeputy Director of the Fiber Optics Research Center RAS, Moscow, Russia. Hisresearch interests cover different aspects of modern fiber optics: fabrication ofpreforms, the fiber drawing process, properties of polymer and hermetic coatings,strength and fatigue of optical fibers, influence of drawing conditions on opticalproperties of optical fibers, development of rare earth-doped as well as highly Ge-and P-doped fibers, photosensitivity of optical fibers, and microstructured fibers.Roman Shubochkin Roman Shubochkin received BS and MS degrees in opticalengineering from Moscow Power Engineering Institute, Moscow, Russia in 1987and 1989, respectively. Between 1989 and 1994, he worked as a Junior ResearchScientist in Fiber Optics and Solid State Physics Departments in the GeneralPhysics Institute of the Russian Academy of Sciences in Moscow. He received anMS and PhD in electrical engineering from Brown University in 1997 and 2003,respectively. Since 2000, he has been a research associate in the LightwaveMendez / Specialty Optical Fibers Handbook prelims Final Proof page xxxiii 31.10.2006 9:35pmList of Contributors xxxiiiTechnology Laboratory at Boston University. Dr. Shubochkins research inter-ests include the study of new techniques and dopants for fabrication of silicafibers, nanopowders, and glasses.Bolesh J. Skutnik Dr. Bolesh J. Skutnik has been with CeramOptec Groupsince 1991. He holds a BS in chemistry/math from Seton Hall University, and anMS and PhD on theoretical physical chemistry from Yale University.Dr. Skutnik has been active in fiber optics since 1979. He is inventor of HardPlastic Clad Silica optical fibers, as well as author of numerous articles andpatents on strength, optical, and radiation behavior of step index fibers.Cheryl A. Smith Cheryl Smith is a sales engineer for CeramOptec Industries,where she is responsible for the investigation of new applications for specialtyfibers. Cheryl has over 20 years of experience in sales and marketing for specialtyfiber optics and lasers.Marin Soljacic Marin Soljacic received his PhD from the physics departmentat Princeton University in 2000. After that, he was a Pappalardo Fellow in thephysics department of MIT. In 2003, he became a Principal Research Scientist atthe Research Lab of Electronics at MIT. Since September 2005, he has been anAssistant Professor of Physics at MIT. He is the recipient of the Adolph Lombmedal from the Optical Society of America (2005). His main research interestsare in photonic crystals and non-linear optics. He is a co-author of 55 scientificarticles and is a co-author of 14 patents.Kanishka Tankala Dr. Kanishka Tankala has been the VP of Operations atNufern since 2000, and involved in the development and commercialization ofspecialty fibers and fiber laser subassemblies. Prior to joining Nufern, he wasTechnical Manager at Lucent Specialty Fiber and a scientist at SpecTran Cor-poration, where he developed a wide range of specialty fibers, including rareearth-doped double-clad fibers and polarization maintaining fibers. He receivedhis MS and PhD from Pennsylvania State University in metals science andengineering. He received his BE in metallurgy from the Indian Institute ofScience and BSc (Hons) in physics from Delhi University, India.Burak Temelkuran Burak Temelkuran was born in Turkey, 1971. He receivedhis BS (1994), MS (1996), and PhD (2000) degrees in physics from BilkentUniversity of Turkey. He received New Focus Student Award in 1999. Heworked as a Postdoctoral Associate at the MIT Research Laboratory ofElectronics and Department of Materials Science and Engineering (20002002)where he became a research scientist (2002). He joined Omniguide Inc. in 2003,where he is currently employed as a Senior Optical Physicist. He has been amember of OSA since 1998. His research interests include photonic band gapmaterials and fibers.Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxxiv 31.10.2006 9:35pmxxxiv List of ContributorsLimin Tong Dr. Limin Tong received his PhD degree in material science andengineering from Zhejiang University in 1997. After four years of assistant andassociate professorship in the Department of Physics in Zhejiang Universityand another three years as a visiting scholar in the Division of Engineering andApplied Science at Harvard University, he joined the Department of OpticalEngineering at Zhejiang University in 2004 and is currently a professor of opticalengineering. Dr. Tongs research area includes nanophotonics and fiber opticdevices.Anthony Toussaint Anthony Toussaint is the Vice President of Research andDevelopment at DSM Desotech. Dr. Toussaint has been with DSM Desotechsince 1997, where he has held several positions in R&D working primarily in thedevelopment of coatings, inks, and matrix materials for fiber optics. He receiveda PhD in chemical engineering from University College London, England and anMBA from Northwestern Universitys Kellogg School of Management.Liming Wang Liming Wang received a PhD degree in optics in 1990 from theChinese Academy of Sciences in China. He then carried on his scientific andengineering career in nonlinear optics and optical materials at the ChineseAcademy of Sciences (China, 19911993), RIKEN and NIRIN (Japan, 19931998), and The University of Chicago (19982001). In 2001, he joined KVHIndustries, Inc. as a Photonics Engineer to participate in the research anddevelopment of new products, including high-speed modulators and componentsfor fiber optic gyroscopes. He is an author and co-author of 60 technical papersin refereed professional journals.Ori Weisberg Ori Weisberg is the former Applications Engineering and SystemsEngineering Group Leader at OmniGuide Inc., where he worked for six years.He received his BS degree in geophysics from Tel-Aviv University, and an MSdegree in planetary science from MIT. He is a co-author of six scientific articlesand a co-inventor of eight patents. He currently resides near Tel-Aviv, Israel.Olaf Ziemann Professor Olaf Ziemann has been the Scientific Director of thePOF-AC at the Nuremberg University of Applied Sciences (FH Nu rnberg) since2001. Dr. Ziemann studied physics at the University of Leipzig and received hisdoctorate degree at the Technical University of Ilmenau in the field of opticaltelecommunications engineering. Between 1995 and March 2001, he worked inthe research center of the Deutsche Telekom (T-Nova) in the special areas ofhybrid access networks and building networks. Since 1996, he has been thechairman of the Information Technology Society-Sub-committee PolymerOptical Fibers (ITG-SC 5.4.1).Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxxv 31.10.2006 9:35pmList of Contributors xxxvThis page intentionally left blankPrefaceThe transport of radiationthrougha flexible, inexpensive conduit has changed ourlives in more ways than we can imagine. The outstanding success of this concept isembodied in the millions of miles of telecommunications fiber that have spannedthe earth, the seas, and utterly transformed the means by which we communicate.This has all been documented with awe over the past several decades.However, more and more, optical fibers are making an impact and seriouscommercial inroads in other fields besides communications, such as in industrialsensing, bio-medical laser delivery systems, military gyro sensors, as well asautomotive lighting and controlto name just a fewand spanned applicationsas diverse as oil well downhole pressure sensors to intra-aortic catheters, to highpower lasers that can cut and weld steel. The requirements imposed by the broadvariety of these new applications have resulted in the evolution of a new subset ofcustom-tailored optical fibers commonly known as specialty fibers, whichhave their material and structure properties modified to render them with newproperties and characteristics.Specialized fibers are increasingly being used to manipulate the guided lightwithin the fiber and to couple light of different wavelengths into and out of thefiber in telecommunications and sensing applications. The field of specialtyoptical fibers calls on the expertise and skills of a broad set of different discip-lines: materials science, ceramic engineering, optics, electrical engineering, phys-ics, polymer chemistry, and several others.There are three fundamental aspects that one can engineer to developa specialty fiber:. Glass composition. Waveguide design. CoatingsGlass composition is one of the most basic fiber parameters and variablesused for the design of specialty fibers. Commonly, it is possible to alter the basicglass structure of a fibersilica based or otherwiseby introducing a number ofappropriate dopants that would act as either glass formers, modifiers or actives,thus changing a fibers basic properties such as refractive index or viscosityor, alternatively, by introducing new properties such as lasing capability,Mendez / Specialty Optical Fibers Handbook prelims Final Proof page xxxvii 31.10.2006 9:35pmxxxviifluorescence, enhanced strain or temperature sensitivity, Brillouin effect coeffi-cient, and many others.Waveguide design was probably the first design parameter exploited and theone that led the way to define single versus multimode fibers. Nowadays wave-guide design is more complex and has resulted in the design of specialty fibersthat range from fibers with more than one guiding core to those based on oneand two dimensional photonic crystal structures.A prevalent characteristic and common feature in many popular commercialspecialty fibers is their coatings. Due to the diverse set of applications anddifferent environmental conditions to which fibers must be subjected to, one ofthe most common tailored properties of specialty fibers tends to be their coating.This has resulted in the commercial availability of a number of different coatedfibers ranging from high temperature polyimides to hermetic carbon coatings.However, more and more, specialty coatings are being designed with specificsensing or actuation purposes and not solely for environmental or mechanicalprotection of the fiber. Coatings can enhance fiber sensitivity and selectivity to anumber of physical and bio-chemical measurands: i.e., humidity, specific hydro-carbons, biochemical agents, electromagnetic fields, etc.Although many specialty optical fibers were originally developed for andspun-off from the optical telecommunications industry, their present demandand design are primarily governed by the special needs and particular specifica-tions imposed by fiber optic sensors and photonic components. Hence, as theneed for optical fiber sensors and specialized components increases, so too willthe demand for specialty fibers. Clear examples of this situation are fiber amp-lifiers and fiber Bragg gratings. Fiber amplifiers require different dopant com-positions and guiding structures, while fiber gratings required photosensitivefibers and mode cladding suppressing designs to facilitate their performance.However, the field of specialty fibers is not without its hurdles. One of themost problematic issues is the fact that specialty fibers tend to be a niche marketand, as the name implies, a specialty item. This means that the volume demandsare small when compared to their telecommunications cousins. Developmenttime and cost are significant in the fabrication of a new, custom fiber. Thedevelopment cost per meter of produced fiber is typically $1001,000. Therefore,unless the application has a significant market and volume demand, many end-users desist in their attempts to have custom-made fibers. As a result, the overallspecialty fiber market tends to be very fragmented and much smaller in size whencompared to the regular telecommunications fiber business. At present, theoverall worldwide market for all specialty fibers is in excess of $150 millionand growing. Nevertheless, one fundamental aim of the specialty fiber industrythat must be maintained is to offer custom tailoring.Although by no means exhaustive, it is the purpose of this volume to provideinsight into the many types of specialty fibers that are novel with respect toMendez / Specialty Optical Fibers Handbook prelims Final Proof page xxxviii 31.10.2006 9:35pmxxxviii Prefacematerials, fiber design, and application. As much as it was practical, we tried tocover as many of the most common and useful specialty fiber types as possible.In a similar way, we strove to provide a balanced and broad coverage of thematerial by ensuring the participation of top experts in the field and from theleading research groups and commercial specialty fiber manufacturers. Much toour disappointment, and not for lack of effort, it was not possible to obtain anycontribution to this volume from Corning.In order to present a comprehensive overview of the different specialty fibertypes, as well as to help support some of their common physics and fundamen-tals, the first six chapters deal with optical fiber technology fundamentals andmarket considerations. The driving forces behind fiber development are eco-nomic, technological, and scientific, and certainly, without an enormouseconomic incentive, fibers would not have become so ubiquitous. It is appropriatethen, that we begin first with a review of the driving factors that have helpeddevelop and grow the specialty fiber industry, and the market opportunities thatmay arise from novel technical advances and the diverse commercial applicationsthat seek these fibers, as discussed in Chapter 1. Any such volume as proposedhere, that in some sense must be self-contained, should certainly carry theintroduction of light-guiding principles and fundamental aspects of fiber designwhich are described in Chapter 2, as well as an overview of the various fiberfabrication techniques employed (Chapter 3). To address the fibers protectionissues, Chapter 4 discusses coating materials and processes. What are the char-acteristics and limitations of fiber coatings? These range from standard coatingsfor telecommunications fibers, to low index polymers for double-clad fibers.Rounding out this group is Chapter 5, which covers some of the newer, morespecialized, single-mode fibers for telecommunications applications such as theultra-low OH fibers, dispersion flattened, and dispersion compensating fibers.Sensing applications utilizing optical fibers, often times have called for eso-teric and non-conventional geometries of single-mode fibers such as dual core,multi-core or exocentric core fibers. Other applications have seen the use offibers with side-holes, embedded metal electrodes or capillary tube holes. Thismyriad of different specialty single-mode fibers are discussed in Chapter 6.Only rare earthdoped elements can lase in an amorphous host, and rareearthdoped fibers appear in a variety of important applications (Chapter 7).The fortuitous concurrence of loss in a silica fiber with the amplification in the1.5 micron region for erbium, has essentially given us wide-band telecommuni-cations systems that span the globe. The other most striking example of anapplication of a rare earthdoped fiber laser is that of the high power Yb laser,with over 1 kW of optical power. Polarization maintaining (PM) fibers are moredifficult to fabricate than fibers that are circularly symmetric. The highest degreeof optical anisotropy is obtained through the insertion of stress rods (PANDA)and anisotropic doping (Bowtie). Such fibers are important for many specialMendez / Specialty Optical Fibers Handbook prelims Final Proof page xxxix 31.10.2006 9:35pmPreface xxxixapplication and are the subject of Chapter 8. Since K.O. Hills discovery of anability to write a grating in glass, UV-induced gratings in optical fibers havebecome an enabling technology that has allowed the possibility of dense WDM(wavelength division multiplexing) that powers the internet. The photosensitivefibers used in the fabrication of fiber Bragg gratings (FBGs) and other devicesare covered in Chapter 9.We tend to think of optical fibers as having a solid core. However, additionalguiding mechanisms appear in a fiber with a hollow core surrounded by layers ofmaterial with sharply differentiated refractive indices. Low loss, endlessly single-mode fibers have been demonstrated, and if the hollow core is filled with a gainmedium, such as an organic dye, new types of lasing phenomena occur. Suchfibers allow for the possibility of transmission in the IR far beyond the 2 mm cutoff of a silica fiber. Chapter 10 describes in detail the fundamentals of hollow-core fibers. In a similar fashion, we also tend to think of the size of a waveguideas being of the order of the wavelength of light it is guiding. However, if thediameter of a guiding structure is significantly smaller than the wavelength,guiding still occursalbeit lossywith a large evanescent wave. Such phenom-ena are not only scientifically of interest, but have significant applications in themeasurement of objects much smaller than the wavelength of light. Chapter 11covers new research work on the analysis and fabrication of sub-wavelengthdiameter fibers and the so-called silica nanowires. Other singular specialty fibertypes, chiral fibers, are studied in Chapter 12. Chiral fibers employ a helicalperiodicity in the core structure, which provides them with unique polarizationas well as wavelength selectivity characteristics.In general, the vast majority of optical fibers are made of silica because of itsextreme optical low loss and amazing physical properties. However, their IRcutoff is near 2 mm, and for many applications that include spectroscopy, sens-ing, or laser delivery, transmission at longer wavelengths is essential. Chapter 13covers the various glass and crystal material candidatessuch as fluoride,chalcogenides, and halide glassesused in mid-IR and IR fibers.It is well known that fibers must be protected from the environment and, inparticular, silica fibers must be protected from moisture attack and OH radicalsthat weaken the fiber. This can lead to additional loss in the core as a conse-quence of the 1380 nm absorption overtone of OH. The need for hermeticcoatingsimpervious to both water moisture and hydrogen gasoccurs inapplications of down-hole logging in oil and gas wells. Here, the elevatedtemperatures accelerate the diffusion of commonly occurring hydrogen mol-ecules into the glass structure, increasing the optical loss and making the needfor fiber protection even more important. One common staple of the specialtyfiber portfolio is the carbon-coated fiber (Chapter 14), which has facilitated theuse of silica fibers in geophysical and other harsh environments. There are somesituations in which an even more rugged protective coating on the fiber isMendez / Specialty Optical Fibers Handbook prelims Final Proof page xl 31.10.2006 9:35pmxl Prefacedesired, either for military or sensing applications. Metal-coated fibers (Chapter15) have been developed for this purpose by applying thin layers of low-tem-perature metals, such as gold, tin, aluminum or copper, and even higher tem-perature alloys, to the glass surface using dipping or evaporation techniques.We had noted previously that PM (polarization maintaining) fibers can beformed through stress anisotropies. Any alteration in azimuthal symmetry in thefiber can remove the degeneracy of the two polarization modes. This can beaccomplished through geometry, as is the case of a fiber with a D-shape for thecladding, or an elliptical shape for the core (Chapter 16).One of the first types of commercial specialty fibers, multimode and large-core plastic clad silica (PCS) fibers, are still in wide demand and enjoy theirconsumption in a variety of applications such as biomedical laser delivery,automotive lighting, LAN networks, and many others. The different glasscompositions and new advances in design are covered in Chapter 17.In photonic devices, there is often a need to include specialty micro-compon-ents to ensure that the efficiency of an all-fiber device is maintained. Theseinclude tapered fibers that allow the NA of a gain section of the device to bematched with suitable pump sources, or in spreading the output intensity of ahigh power fiber laser with a predetermined near- and far-field pattern. Thesedevices and their design aspects are described in Chapter 18.Some of the earliest examples of guiding structures in fibers were provided byinserting higher optical density liquids into the core of a hollow fiber. Theseliquid-core fibers still have many applications in UV light delivery and spectros-copy (Chapter 19).There are many situations in which ultra-low loss is not a necessity to fulfill aspecific design application, and polymeric optical fibers (POF) can often beemployed, as discussed in Chapter 21. This has been a steadily growing andmaturing area, and the automotive industry has been particularly interested inthis field. Moreover, polymeric fibers with a more efficient graded index havebeen developed, and losses can now be as low as 40 dB/km.Although silica fibers can be used as temperature sensors up to approximately1,100 8C, there is interest in a material that could withstand higher temperaturesand harsh, corrosive environments. Sapphire fibers, in short lengths, can meetthis demand. They are grown from a pedestal technique as single crystal strands,and the smallest diameter is 150 mm. These fibers fulfill a need in spectroscopy inthat they are able to transmit further in the IR than a silica fiber (Chapter 21).One of the great successes of specialty optical fibers is the advent of the highpower Yb fiber laser. Nowadays, fiber lasers are available in the multi-kW range,and single mode operation now exceeds 2,000W CW. The materials processingmarket for industrial lasers is approximately $2 billion/year, and high powerdouble clad fiber lasers are garnering an ever-increasing share. With 1.5 kW it ispossible to cut through thick steel. In cutting applications that utilize plasmaMendez / Specialty Optical Fibers Handbook prelims Final Proof page xli 31.10.2006 9:35pmPreface xlitechnology, carbon dioxide lasers, or YAG lasers, it is expected that with thereduced cost of high power pump diodes, high power fiber laser systems mayprove to be a disruptive technology. We expect that industrial laser applica-tions will grow significantly over the next few years. The specialty fibers needed infiber lasers and their industrial applications are covered in detail in Chapter 22.In biomedical applications, the advantages of fibers are easy to enumerate.A silica fiber is biologically inert, its small size allows it to enter the body as acatheter go to any place in the blood system to remove plaque, unclog arteries, orremove cysts. This is clearly a growing area of applications and one where newdevelopments should be expected. Chapter 23 describes fiber delivery systems,specialty fibers required and applications in the biomedical area.Our final chapter reports on the mechanical strength and reliability of glassfibers. This knowledge is of considerable importance to the design engineer inapplying silica fibers to non-telecommunications applications.In summary, we have presented what we believe to be a fairly completeoverview of the many different types of specialty optical fibers, their uses, andthe expected directions in which this field will develop, both with regard toelements of basic science as well as applications of this technology. We havesought to enlist the contributions of individuals who have made their mark in themany disparate areas of this field. We hope that this volume may prove helpfulto those who wish to further their knowledge of the basic fundamentals ofspecialty fibers and how their special properties may provide solutions to real-life applications.A. MendezT.F. MorseMendez / Specialty Optical Fibers Handbook prelims Final Proof page xlii 31.10.2006 9:35pmxlii PrefaceChapter 1Specialty Optical FiberMarket OverviewStephen MontgomeryElectroniCast Corp., San Mateo, California1.1 MARKET OVERVIEWElectroniCast has studied the potential use and market consumption fora variety of specialty optical fibers. All of the fiber types studied show veryimpressive historic and future growth potential. A few of the near-term stand-outsin value potentialinclude polarization (PZ), ytterbium-doped, disper-sion-compensating, and photosensitive fibers. Growth is also foreseen for newmore esoteric and highly advanced fibers, such as holey fibers (photoniccrystal fibers).The global consumption of selected specialty optical fiberswhich is com-posed of actual product sales and research and development (R&D) produc-tionhas been expanding rapidly from $239 million in 2000 to reach aforecasted estimate of $4380 million by 2010 (Fig. 1.1). This growth is driven bythe challenges presented by the requirements of greater distances (kilometers/linklengths), optical fiber amplifiers (OFAs), dispersion compensation, attenuation,higher data rates, increased number of wavelengths (DWDM), high-poweredfiber lasers, and simply the increase in the number of applications, components,and modulesjust to name a few drivers.1.1.1 Production Versus ConsumptionThe actual consumption (use) of specialty optical fibers in internal andexternal R&D applications and in commercial consumption exceeded the pro-duction rates in recent years. This factor has since been corrected, because earlierexcess inventory of fiber has been absorbed to more manageable levels.Mendez / Specialty Optical Fibers Handbook ch01 Final Proof page 1 26.10.2006 6:46pm1At all levels in the fiber optic industry food chain, there is general agree-ment that there has been a return to substantial growth, which started in 2004,though not at the dramatic pace seen in North American long-haul/submarinetelecommunications in 19992000.The unusually strong fiber optics growth during 19992000, and unusuallydrastic collapse in 20012002, was more a function of investment communitysupport than a shift in the basic demand for services. Both venture capital (VC)and mature investment in forward-looking networks (and their supportingequipment and components) collapsed. New networks were frozen in a semi-functional state. Equipment orders were canceled, rippling down through com-ponents and devices/parts.1.1.2 Rapidly Growing Need to Use Fiber OpticSensorsThere is a rapidly growing need to use fiber optic sensors, a major consumerof specialty optical fiber. The wide range of applications (uses) for fiber opticsensors is facilitated by the need for various measurands (types of measure-ments). Because of the relative average price per unit, Fiber Optic Gyros20%20%High IndexOther Types40%19%24%7%13%10%9%14%Photo-sensitive ER DopedPMF8%2010$4380 Million2000$239.5 Million2005$1124 Million11%19%35%51%Figure 1.1 Estimated total specialty optical fiber global consumption forecast by type.Mendez / Specialty Optical Fibers Handbook ch01 Final Proof page 2 26.10.2006 6:46pm2 Specialty Optical Fiber Market Overview(FOGs) sensors, which are used in Military/Aerospace and commercial guidancecontrol applications, is a leading sensor product or function type in terms ofconsumption value. Additional major fiber optic sensor functions (measurands),which contribute to the use of specialty optic fiber, include but by no means arelimited to the following:. Strain. Temperature. Flow. Pressure. Gas, liquid. Acoustic, seismic, vibration. Detection of objects/sampling. Magnetic/electric field. Wavelength monitoring/color1.1.3 Weapon System DevelopmentFor various security, economic, political, and various other reasons, the U.S.weapon system development, production, and deployment is trending towardmaximum reliance on the latest possible technologies that may be brought for-ward to deployment, with reduced dependence on deployment of extensive man-power. The succeeding generations of advanced electronic and optical/photoniccapability, however, are advancing much faster than the technologies of thevehicles or shelters that house these advanced systems. This leads, therefore, tothe concept that a major vehicle, such as a fighter aircraft, ship, or intercontinentalmissile, may need to accommodate the insertion of three or four succeedinggenerations of systems before the basic vehicle or shelter becomes obsolete.1.1.4 10010003Improvements in PerformanceEach succeeding military/aerospace system typically achieves a factor of 100-to 1000-fold improvement in performance but must be inserted into the same orsmaller volume, with the same or smaller weight. Huge improvements have beenmade, resulting in smaller bend radius conditions, for example, which makespecialty fibers ideal for other applications as well, including medical applica-tions, consuming specialty optical fiber. The use of fiber optics, instead of copperconductors, for high data rate signal transmission and to address EMI/RFI, size/volume, and weight issues, is part of the answer to this challenge. These inter-connects, however, must have very high performance reliabi