The most complete, one-stop reference for fiber optic sensor theory and application

Optical Fiber Sensors: Fundamentals for Development of Optimized Devices constitutes the most complete, comprehensive, and up-to-date reference on the development of optical fiber sensors. Edited by two respected experts in the field and authored by experienced engineers and scientists, the book acts as a guide and a reference for an audience ranging from graduate students to researchers and engineers in the field of fiber optic sensors.

The book discusses the fundamentals and foundations of fiber optic sensor technology and provides real-world examples to illuminate and illustrate the concepts found within. In addition to the basic concepts necessary to understand this technology, Optical Fiber Sensors includes chapters on:

• Distributed sensing with Rayleigh, Raman and Brillouin scattering methods
• Biomechanical sensing
• Gas and volatile organic compound sensors
• Application of nanotechnology to optical fiber sensors
• Health care and clinical diagnosis
• And others

Graduate students as well as professionals who work with optical fiber sensors will find this volume to be an indispensable resource and reference.

Autorentext

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.

Inhalt

List of Contributors xv

Acknowledgment xix

About the Editors xxi

1 Introduction **1
**Ignacio R. Matias and Ignacio Del Villar

References 14

2 Propagation of Light Through Optical Fibre **17
**Ignacio Del Villar

2.1 Geometric Optics 17

2.2 Wave Theory 22

2.2.1 Scalar Analysis 23

2.2.2 Vectorial Analysis 26

2.3 Fibre Losses and Dispersion 32

2.4 Propagation in Microstructured Optical Fibre 35

2.5 Propagation in Specialty Optical Fibres Focused on Sensing 37

2.6 Conclusion 45

References 46

3 Optical Fibre Sensor Set-Up Elements **49
**Minghong Yang and Dajuan Lyu

3.1 Introduction 49

3.2 Light Sources 50

3.2.1 Light-Emitting Diodes 52

3.2.1.1 Surface Light-Emitting Diode 52

3.2.1.2 Side Light-Emitting Diode 52

3.2.2 Laser Diode 53

3.2.2.1 Single-Mode Laser Diode Structure 54

3.2.2.2 Quantum Well Laser Diode 56

3.2.3 Superluminescent Diodes (SLD) 56

3.2.4 Amplified Spontaneous Emission Sources 59

3.2.5 Narrow Line Broadband Sweep Source 62

3.2.6 Broadband Sources 62

3.3 Optical Detectors 63

3.3.1 Basic Principles of Optical Detectors 64

3.3.1.1 PN Photodetector 64

3.3.1.2 PIN Photodetector 65

3.3.1.3 Avalanche Photodiode (APD) 66

3.3.2 Main Characteristics of Optical Detectors 66

3.3.2.1 Operating Wavelength Range and Cut-Off Wavelength 66

3.3.2.2 Quantum Efficiency and Responsiveness 67

3.3.2.3 Response Time 68

3.3.2.4 Materials and Structures of Semiconductor Photodiodes 69

3.3.3 Optical Spectrometers 70

3.4 Light Coupling Technology 71

3.4.1 Coupling of Fibre and Light Source 71

3.4.1.1 Coupling of Semiconductor Lasers and Optical Fibres 71

3.4.1.2 Coupling Loss of Semiconductor Light-Emitting Diodes and Optical Fibres 72

3.4.2 Multimode Fibre Coupled Through Lens 72

3.4.3 Direct Coupling of Fibre and Fibre 73

3.5 Fibre-Optic Device 74

3.5.1 Fibre Coupler 74

3.5.2 Optical Isolator 74

3.5.3 Optical Circulator 76

3.5.4 Fibre Attenuator 76

3.5.5 Fibre Polarizer 76

3.5.6 Optical Switch 77

3.6 Optical Modulation and Interrogation of Optical Fibre-Optic Sensors 77

3.6.1 Intensity-Modulated Optical Fibre Sensing Technology 78

3.6.1.1 Reflective Intensity Modulation Sensor 78

3.6.1.2 Transmissive Intensity Modulation Sensor 80

3.6.1.3 Light Mode (Microbend) Intensity Modulation Sensor 80

3.6.1.4 Refractive Index Intensity-Modulated Fibre-Optic Sensor 80

3.6.2 Wavelength Modulation Optical Fibre Sensing Technology 81

3.6.2.1 Direct Demodulation System 81

3.6.2.2 NarrowBand Laser Scanning System 82

3.6.2.3 Broadband Source Filter Scanning System 83

3.6.2.4 Linear Sideband Filtering Method 84

3.6.2.5 Interference Demodulation System 84

3.6.3 Phase Modulation Optical Fibre Sensing Technology 86

References 87

4 Basic Detection Techniques **91
**Daniele Tosi and Carlo Molardi

4.1 Introduction 91

4.2 Overview of Interrogation Methods 93

4.3 Intensity-Based Sensors 97

4.3.1 Macrobending 97

4.3.2 In-Line Fibre Coupling 99

4.3.3 Bifurcated Fibre Bundle 100

4.3.4 Smartphone Sensors 100

4.4 Polarization-Based Sensors 102

4.4.1 Pressure and Force Detection 102

4.4.2 Lossy Mode Resonance for Refractive Index Sensing 104

4.5 Fibre-Optic Interferometers 105

4.5.1 Fabry-Pérot Interferometer (FPI)-Based Fibre Sensors 106

4.5.1.1 Extrinsic FPI for Pressure Sensing 107

4.5.1.2 In-Line FPI for Temperature Sensing 108

4.5.2 Mach-Zehnder Interferometer (MZI)-Based Fibre Sensors 109

4.5.3 Single-Multi-Single Mode (SMS) Interferometer-Based Fibre Sensors 109

4.6 Grating-Based Sensors 111

4.6.1 Fibre Bragg Grating (FBG) 111

4.6.2 FBG Arrays 113

4.6.3 Tilted and Chirped FBG 115

4.6.4 Long-Period Grating (LPG) 117

4.6.5 FBG Fabrication 118

4.7 Conclusions 121

References 121

5 Structural Health Monitoring Using Distributed Fibre-Optic Sensors **125
**Alayn Loayssa

5.1 Introduction 125

5.2 Fundamentals of Distributed Fibre-Optic Sensors 126

5.2.1 Raman DTS 128

5.2.2 Brillouin DTSS 129

5.3 DFOS in Civil and Geotechnical Engineering 130

5.3.1 Bridges 133

5.3.2 Tunnels 134

5.3.3 Geotechnical Structures 137

5.4 DFOS in Hydraulic Structures 141

5.5 DFOS in the Electric Grid 143

5.6 Conclusions 145

References 146

6 Distributed Sensors in the Oil and Gas Industry **151
**Arthur H. Hartog

6.1 The Late Life Cycle of a Hydrocarbon Molecule 153

6.1.1 Upstream 154

6.1.1.1 Exploration 154

6.1.1.2 Well Construction 155

6.1.1.3 Formation and Reservoir Evaluation 157

6.1.1.4 Production 158

6.1.1.5 Production of Methane Hydrates 159

6.1.1.6 Well Abandonment 160

6.1.2 Midstream: Transportation 160

6.1.3 Downstream: Refinery and Distribution 161

6.2 Challenges in the Application of Optical Fibres to the Hydrocarbon 161

6.2.1 Conditions 161

6.2.2 Conveyance Methods 162

6.2.2.1 Temporary Installations (Intervention Services) 163

6.2.2.2 Permanent Fibre Installations 163

6.2.3 Fibre Reliability 165

6.2.4 Fibre Types 166

6.3 Applications and Take-Up 168

6.3.1 Steam-Assisted Recovery; SAGD 168

6.3.2 Flow Allocation: Conventional Wells 171

6.3.3 Injector Monitoring 174

6.3.4 Thermal Tracer Techniques 175

6.3.5 Water Flow Between Wells 176

6.3.6 Gas-Lift Valves 176

6.3.7 Vertical Seismic Profiling (VSP) 177

6.3.8 Hydraulic Fracturing Monitoring (HFM) 184

6.3.9 Sand Production 185

6.4 Summary 186

References 186

7 Biomechanical Sensors **193
**Cicero Martelli, Jean Carlos Cardozo da Silva, Alessandra Kalinowski, José Rodolfo Galvão, and Talita Paes

7.1 Optical Fibre Sensors in Biomechanics: Introduction and Review 193…