Optical Fibre Sensors

IGNACIO DEL VILLAR, PhD, is an Associate Professor in the Electrical, Electronic and Communications Engineering Department at the Public University of Navarra, Spain, where he teaches on electronics and industrial communications. He is a member of the IEEE and an Associate Editor of different journals. In addition, he has participated in multiple research projects and co-authored more than 150 papers, conferences, and book chapters related to fibre-optic sensors. IGNACIO R. MATIAS, PhD, is the Scientific Director of the Institute of Smart Cities and Professor of the Electrical, Electronic and Communications Department at the Public University of Navarra, Spain. He was one of the Associate Editors who founded the IEEE Sensors Journal, promoting fibre optic sensors since then through conferences, special issues, awards, books, etc. He has coauthored more than 500 book chapters, journal and conference papers related to optical fibre sensors. He is currently member-at-large at the IEEE Sensors Council AdCom.

• List of Contributors xvAcknowledgment xixAbout the Editors xxi1 Introduction 1Ignacio R. Matias and Ignacio Del VillarReferences 142 Propagation of Light Through Optical Fibre 17Ignacio Del Villar2.1 Geometric Optics 172.2 Wave Theory 222.2.1 Scalar Analysis 232.2.2 Vectorial Analysis 262.3 Fibre Losses and Dispersion 322.4 Propagation in Microstructured Optical Fibre 352.5 Propagation in Specialty Optical Fibres Focused on Sensing 372.6 Conclusion 45References 463 Optical Fibre Sensor Set-Up Elements 49Minghong Yang and Dajuan Lyu3.1 Introduction 493.2 Light Sources 503.2.1 Light-Emitting Diodes 523.2.1.1 Surface Light-Emitting Diode 523.2.1.2 Side Light-Emitting Diode 523.2.2 Laser Diode 533.2.2.1 Single-Mode Laser Diode Structure 543.2.2.2 Quantum Well Laser Diode 563.2.3 Superluminescent Diodes (SLD) 563.2.4 Amplified Spontaneous Emission Sources 593.2.5 Narrow Line Broadband Sweep Source 623.2.6 Broadband Sources 623.3 Optical Detectors 633.3.1 Basic Principles of Optical Detectors 643.3.1.1 PN Photodetector 643.3.1.2 PIN Photodetector 653.3.1.3 Avalanche Photodiode (APD) 663.3.2 Main Characteristics of Optical Detectors 663.3.2.1 Operating Wavelength Range and Cut-Off Wavelength 663.3.2.2 Quantum Efficiency and Responsiveness 673.3.2.3 Response Time 683.3.2.4 Materials and Structures of Semiconductor Photodiodes 693.3.3 Optical Spectrometers 703.4 Light Coupling Technology 713.4.1 Coupling of Fibre and Light Source 713.4.1.1 Coupling of Semiconductor Lasers and Optical Fibres 713.4.1.2 Coupling Loss of Semiconductor Light-Emitting Diodes and Optical Fibres 723.4.2 Multimode Fibre Coupled Through Lens 723.4.3 Direct Coupling of Fibre and Fibre 733.5 Fibre-Optic Device 743.5.1 Fibre Coupler 743.5.2 Optical Isolator 743.5.3 Optical Circulator 763.5.4 Fibre Attenuator 763.5.5 Fibre Polarizer 763.5.6 Optical Switch 773.6 Optical Modulation and Interrogation of Optical Fibre-Optic Sensors 773.6.1 Intensity-Modulated Optical Fibre Sensing Technology 783.6.1.1 Reflective Intensity Modulation Sensor 783.6.1.2 Transmissive Intensity Modulation Sensor 803.6.1.3 Light Mode (Microbend) Intensity Modulation Sensor 803.6.1.4 Refractive Index Intensity-Modulated Fibre-Optic Sensor 803.6.2 Wavelength Modulation Optical Fibre Sensing Technology 813.6.2.1 Direct Demodulation System 813.6.2.2 NarrowBand Laser Scanning System 823.6.2.3 Broadband Source Filter Scanning System 833.6.2.4 Linear Sideband Filtering Method 843.6.2.5 Interference Demodulation System 843.6.3 Phase Modulation Optical Fibre Sensing Technology 86References 874 Basic Detection Techniques 91Daniele Tosi and Carlo Molardi4.1 Introduction 914.2 Overview of Interrogation Methods 934.3 Intensity-Based Sensors 974.3.1 Macrobending 974.3.2 In-Line Fibre Coupling 994.3.3 Bifurcated Fibre Bundle 1004.3.4 Smartphone Sensors 1004.4 Polarization-Based Sensors 1024.4.1 Pressure and Force Detection 1024.4.2 Lossy Mode Resonance for Refractive Index Sensing 1044.5 Fibre-Optic Interferometers 1054.5.1 Fabry–Pérot Interferometer (FPI)-Based Fibre Sensors 1064.5.1.1 Extrinsic FPI for Pressure Sensing 1074.5.1.2 In-Line FPI for Temperature Sensing 1084.5.2 Mach–Zehnder Interferometer (MZI)-Based Fibre Sensors 1094.5.3 Single-Multi-Single Mode (SMS) Interferometer-Based Fibre Sensors 1094.6 Grating-Based Sensors 1114.6.1 Fibre Bragg Grating (FBG) 1114.6.2 FBG Arrays 1134.6.3 Tilted and Chirped FBG 1154.6.4 Long-Period Grating (LPG) 1174.6.5 FBG Fabrication 1184.7 Conclusions 121References 1215 Structural Health Monitoring Using Distributed Fibre-Optic Sensors 125Alayn Loayssa5.1 Introduction 1255.2 Fundamentals of Distributed Fibre-Optic Sensors 1265.2.1 Raman DTS 1285.2.2 Brillouin DTSS 1295.3 DFOS in Civil and Geotechnical Engineering 1305.3.1 Bridges 1335.3.2 Tunnels 1345.3.3 Geotechnical Structures 1375.4 DFOS in Hydraulic Structures 1415.5 DFOS in the Electric Grid 1435.6 Conclusions 145References 1466 Distributed Sensors in the Oil and Gas Industry 151Arthur H. Hartog6.1 The Late Life Cycle of a Hydrocarbon Molecule 1536.1.1 Upstream 1546.1.1.1 Exploration 1546.1.1.2 Well Construction 1556.1.1.3 Formation and Reservoir Evaluation 1576.1.1.4 Production 1586.1.1.5 Production of Methane Hydrates 1596.1.1.6 Well Abandonment 1606.1.2 Midstream: Transportation 1606.1.3 Downstream: Refinery and Distribution 1616.2 Challenges in the Application of Optical Fibres to the Hydrocarbon 1616.2.1 Conditions 1616.2.2 Conveyance Methods 1626.2.2.1 Temporary Installations (Intervention Services) 1636.2.2.2 Permanent Fibre Installations 1636.2.3 Fibre Reliability 1656.2.4 Fibre Types 1666.3 Applications and Take-Up 1686.3.1 Steam-Assisted Recovery; SAGD 1686.3.2 Flow Allocation: Conventional Wells 1716.3.3 Injector Monitoring 1746.3.4 Thermal Tracer Techniques 1756.3.5 Water Flow Between Wells 1766.3.6 Gas-Lift Valves 1766.3.7 Vertical Seismic Profiling (VSP) 1776.3.8 Hydraulic Fracturing Monitoring (HFM) 1846.3.9 Sand Production 1856.4 Summary 186References 1867 Biomechanical Sensors 193Cicero Martelli, Jean Carlos Cardozo da Silva, Alessandra Kalinowski, José Rodolfo Galvão, and Talita Paes7.1 Optical Fibre Sensors in Biomechanics: Introduction and Review 1937.2 Optical Fibre Sensors: From Experimental Phantoms to In Vivo Applications 1987.2.1 Experimental Phantoms and Models 1987.2.1.1 Joints 1997.2.1.2 Bones and Muscles 1997.2.1.3 Teeth, Lower Jaw (Mandible), and Upper Jaw (Maxilla) 2007.2.1.4 Prosthesis and Extracorporeal Devices 2007.2.1.5 Sole and Insoles 2017.2.1.6 Smart Fabrics 2017.2.1.7 Blood Vessels 2027.2.1.8 Respiratory Monitoring 2037.2.2 In Vitro 2037.2.3 Ex Vivo 2047.2.3.1 Joints 2047.2.3.2 Bones and Muscles 2057.2.3.3 Teeth, Lower Jaw (Mandible), and Upper Jaw (Maxilla) 2057.2.3.4 Blood Vessels 2057.2.3.5 Mechanical Properties of Tissues 2077.2.4 In Vivo 2077.2.4.1 Joints 2077.2.4.2 Bones and Muscles 2077.2.4.3 Teeth, Lower Jaw (Mandible) and Upper Jaw (Maxilla) 2087.2.4.4 Blood Vessels 2087.2.4.5 Respiratory Monitoring 2087.2.5 In Situ 2087.2.5.1 Joints 2097.2.5.2 Bones and Muscles 2097.2.5.3 Prostheses and Extracorporeal Devices 2107.2.5.4 Soles and Insoles 2107.2.5.5 Cardiac Monitoring 2117.2.5.6 Respiratory Monitoring 2117.3 FBG Sensors Integrated into Mechanical Systems 2137.3.1 FBG Sensors Glued with Polymer 2147.3.2 Polymer-Integrated FBG Sensor 2157.3.3 Smart Fibre Reinforced Polymer (SFRP) 2187.4 Future Perspective 222Acknowledgment 223References 2248 Optical Fibre Chemical Sensors 239T. Hien Nguyen and Tong Sun8.1 Introduction 2398.2 Principles and Mechanisms of Fibre-Optic-Based Chemical Sensing 2408.2.1 Principle of Chemical Sensor Response 2408.2.2 Absorption-Based Sensors 2428.2.3 Luminescence-Based Sensors 2438.2.4 Surface Plasmon Resonance (SPR)-Based Sensors 2458.3 Sensor Design and Applications 2478.3.1 Optical Fibre pH Sensors 2478.3.1.1 Principle of Fluorescence-Based pH Measurements 2488.3.1.2 pH Sensor Design 2498.3.1.3 Set-Up of a pH Sensor System 2538.3.1.4 Evaluation of the pH Sensor Systems 2548.3.1.5 Comments 2608.3.2 Optical Fibre Mercury Sensor 2618.3.2.1 Sensor Design and Mechanism 2628.3.2.2 Evaluation of the Mercury Sensor System 2658.3.2.3 Comments 2718.3.3 Optical Fibre Cocaine Sensor 2718.3.3.1 Sensing Methodology 2728.3.3.2 Design and Fabrication of a Cocaine Sensor System 2738.3.3.3 Evaluation of the Cocaine Sensor System 2758.3.3.4 Comments 2808.4 Conclusions and Future Outlook 281Acknowledgements 282References 2829 Application of Nanotechnology to Optical Fibre Sensors: Recent Advancements and New Trends 289Armando Ricciardi, Marco Consales, Marco Pisco, and Andrea Cusano9.1 Introduction 2899.2 A View Back 2929.3 Nanofabrication Techniques on the Fibre Tip for Biochemical Applications 2939.3.1 Direct Approaches 2949.3.2 Indirect Approaches 3019.3.3 Self-Assembly 3059.3.4 Smart Materials Integration 3079.4 Nanofabrication Techniques on the Fibre Tip for Optomechanical Applications 3099.5 Conclusions 317References 32010 From Refractometry to Biosensing with Optical Fibres 331Francesco Chiavaioli, Ambra Giannetti, and Francesco Baldini10.1 Basic Sensing Concepts and Parameters for OFSs 33210.1.1 Parameters of General Interest 33510.1.1.1 Uncertainty 33510.1.1.2 Accuracy and Precision 33510.1.1.3 Sensor Drift and Fluctuations 33610.1.1.4 Repeatability 33610.1.1.5 Reproducibility 33610.1.1.6 Response Time 33610.1.2 Parameters Related to Volume RI Sensing 33710.1.2.1 Refractive Index Sensitivity 33710.1.2.2 Resolution 33810.1.2.3 Figure of Merit (FOM) 33910.1.3 Parameters Related to Surface RI Sensing 33910.1.3.1 Sensorgram and Calibration Curve 34010.1.3.2 Limit of Detection (LOD) and Limit of Quantification (LOQ) 34110.1.3.3 Specificity (or Selectivity) 34510.1.3.4 Regeneration (or Reusability) 34510.2 Optical Fibre Refractometers 34710.2.1 Optical Interferometers 34810.2.2 Grating-Based Structures 34810.2.3 Other Resonance-Based Structures 35010.3 Optical Fibre Biosensors 35210.3.1 Immuno-Based Biosensors 35310.3.2 Oligonucleotide-Based Biosensors 35410.3.3 Whole Cell/Microorganism-Based Biosensors 35710.4 Fibre Optics Towards Advanced Diagnostics and Future Perspectives 360References 36111 Humidity, Gas, and Volatile Organic Compound Sensors 367Diego Lopez-Torres and César Elosua11.1 Introduction 36711.2 Optical Fibre Sensor Specific Features for Gas and VOC Detection 36811.3 Sensing Materials 37011.3.1 Organic Chemical Dyes 37011.3.2 Metal–Organic Framework (MOF) Materials 37211.3.3 Metallic Oxides 37411.3.4 Graphene 37811.4 Detection of Single Gases 37911.5 Relative Humidity Measurement 38311.6 Devices for VOC Sensing and Identification 38411.7 Artificial Systems for Complex Mixtures of VOCs: Optoelectronic Noses 38711.8 Conclusions 391References 39212 Interaction of Light with Matter in Optical Fibre Sensors: A Biomedical Engineering Perspective 399Sillas Hadjiloucas12.1 Introduction 39912.2 Energy Content in Light and Its Effect in Chemical Processes 39912.3 Relevance of Wien’s Law to Physicochemical Processes 40212.4 Absorption of Light Molecules 40312.5 The Role of Electron Spin and State Multiplicity in Spectroscopy 40412.6 Molecular Orbitals, Bond Conjugation, and Photoisomerization 40612.7 De-excitation Processes Through Competing Pathways: Their Effect on Lifetimes and Quantum Yield 40712.8 Energy Level Diagrams and Vibrational Sublevels 41212.9 Distinction Between Absorption and Action Spectra 41312.10 Light Scattering Processes 41412.10.1 Elastic Scattering 41412.10.2 Inelastic Scattering 41612.11 Induction of Non-linear Optical Processes 41812.12 Concentrating Fields to Maximize Energy Exchange in the Measurement Process Using Slow Light 41912.12.1 Slow Light Using Atomic Resonances and Electromagnetically Induced Transparency 41912.12.2 Slow Light Using Photonic Resonances 42412.13 Field Enhancement and Improved Sensitivity Through Whispering Gallery Mode Structures 42712.14 Emergent Technological Trends Facilitating Multi-parametric Interactions of Light with Matter 42912.14.1 Integration of Optical Fibres with Microfluidic Devices and MEMS 42912.14.2 Pump–Probe Spectroscopy 43012.15 Prospects of Molecular Control Using Femtosecond Fibre Lasers 43012.15.1 Femtosecond Pulse Shaping 43012.15.2 New Opportunities for Coherent Control of Molecular Processes 43212.15.3 Developments in Evolutionary Algorithms for Molecular Control 434References 43613 Detection in Harsh Environments 441Kamil Kosiel and Mateusz Śmietana13.1 Introduction 44113.2 Optical Fibre Sensors for Harsh Environments 44213.3 Need for Harsh Environment Sensing Based on Optical Fibres 44313.4 General Requirements for Harsh Environment OFSs 44913.5 Silica Glass Optical Fibres for Harsh Environment Sensing 45113.6 Polymer Optical Fibres for Harsh Environment Sensing 46113.7 Chalcogenide Glass and Polycrystalline Silver Halide Optical Fibres for Harsh Environment Sensing 46413.8 Monocrystalline Sapphire Optical Fibres for Harsh Environment Sensing 46713.9 Future Trends in Optical Fibre Sensing 469References 47014 Fibre-Optic Sensing: Past Reflections and Future Prospects 477Brian Culshaw and Marco N. Petrovich14.1 Introductory Comments 47714.2 Reflections on Achievements to Date 47814.3 Photonics: How is It Changing? 48414.4 Some Future Speculation 48614.4.1 Photonic Integrated and Plasmonic Circuits 48714.4.2 Metamaterials in Sensing 49014.4.3 More Variations on the Nano Story 49214.4.4 Improving the Signal-to-Noise Ratio 49314.4.5 Quantum Sensing, Entanglement, and the Like 49414.4.6 The Many Prospects in Fibre Design and Fabrication 49514.4.7 Technologies Other than Photonics 50014.4.8 Societal Aspirations in Sensor Technology 50114.4.9 The Future and a Quick Look at the Sensing Alternatives 50114.4.10 So What Has Fibre Sensing Achieved to Date 50314.5 Concluding Observations 504References 504Index 511

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