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- Sprache: Englisch
Optical Fiber Sensing Technologies
Explore foundational and advanced topics in optical fiber sensing technologies
In Optical Fiber Sensing Technologies: Principles, Techniques, and Applications, a team of distinguished researchers delivers a comprehensive overview of all critical aspects of optical fiber sensing devices, systems, and technologies. The book moves from the basic principles of the technology to innovation methods and a broad range of applications, including Bragg grating sensing technology, intra-cavity laser gas sensing technology, optical coherence tomography, distributed vibration sensing, and acoustic sensing.
The accomplished authors bridge the gap between innovative new research in the field and practical engineering solutions, offering readers an unmatched source of practical, application-ready knowledge.
Ideal for anyone seeking to further the boundaries of the science of optical fiber sensing or the technological applications for which these techniques are used, Optical Fiber Sensing Technologies: Principles, Techniques, and Applications also includes:
- Thorough introductions to optical fiber and optical devices, as well as optical fiber Bragg grating sensing technology
- Practical discussions of Extrinsic-Fabry-Perot-Interferometer-based optical fiber sensing technology, acoustic sensing technology, and high-temperature sensing technology
- Comprehensive explorations of assemble free micro-interferometer-based optical fiber sensing technology
- In-depth examinations of optical fiber intra-cavity laser gas sensing technology
Perfect for applied and semiconductor physicists, Optical Fiber Sensing Technologies: Principles, Techniques, and Applications is also an invaluable resource for professionals working in the semiconductor, optical, and sensor industries, as well as materials scientists and engineers for measurement and control.
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Seitenzahl: 1433
Veröffentlichungsjahr: 2021
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Table of Contents
Cover
Title Page
Title Page
Copyright
Volume 1
Preface
1 Optical Fiber and Optical Devices
1.1 Optical Fiber
1.2 Light Source
1.3 Optical Amplifier
1.4 Detector
1.5 Optical Fiber Passive Device
1.6 Optical Fiber Modulator
References
Part I: Discrete Optical Fiber Sensing
2 Optical Fiber Bragg Grating Sensing Technology
2.1 Principle of Fiber Bragg Grating Sensing
2.2 Photosensitivity of Ge‐Doped Fiber
2.3 Fabrication of Fiber Bragg Grating
2.4 Package Design for Strain and Temperature Sensing
2.5 Demodulation of Fiber Bragg Grating Sensing for Space Application
References
3 Extrinsic Fabry–Pérot Interferometer‐Based Optical Fiber Sensing Technology
3.1 Principle of Fabry–Pérot Interferometer
3.2 Fabry–Pérot Interferometer‐Based Optical Fiber Sensor Structure
3.3 Optical Fiber Fabry–Pérot Interferometer Sensor Based on MEMS
3.4 Polarization Low‐Coherence Interference Demodulation for Pressure Sensing
3.5 Application
References
4 Extrinsic Fabry–Perot Interferometer‐Based Optical Fiber Acoustic Sensing Technology
4.1 Polymer Diaphragm Optical Fiber Acoustic Sensor
4.2 Sensor Design and Parameters Optimization
4.3 Demodulation
4.4 Optical Fiber Acoustic Sensing in Space Application
References
5 Extrinsic Fabry–Perot Interferometer‐Based Optical Fiber High‐Temperature Sensing Technology
5.1 Sapphire Material Characteristic
5.2 Sapphire Fiber Fabry–Perot High‐Temperature Sensor Design and Fabrication
5.3 Sapphire Fiber Fabry–Perot High‐Temperature Sensing Demodulation System
5.4 Analysis of Sensing Performance of Sapphire Fiber Fabry–Perot High‐Temperature Sensor
5.5 Self‐Filtering High Fringe Contrast Sapphire Fiber Fabry–Perot High‐Temperature Sensor
5.6 Summary
References
6 Assembly‐Free Micro‐interferometer‐Based Optical Fiber Sensing Technology
6.1 Assembly‐Free In‐Fiber Micro‐interferometer
6.2 Optical Fiber Sensor Based on Fiber Tip Micro‐Michelson Interferometer
6.3 Optical Fiber Sensor Based on In‐Line Mach–Zehnder Interferometer
6.4 Optical Fiber Sensor Based on Fabry–Perot Interferometer
6.5 Discussion and Conclusion
References
7 Surface Plasmon Resonance‐Based Optical Fiber Sensing Technology
7.1 Coating of Optical Fiber
7.2 Theoretical Modeling Multimode Optical Fiber Sensor Based on SPR
7.3 EMD‐Based Filtering Algorithm
References
8 Sagnac Interferometer‐Based Optical Fiber Sensing Technology
8.1 Principle of Sagnac Interferometer
8.2 Optical Fiber Gyroscope (FOG)
8.3 Optical Fiber Coil Quality Inspection Method
8.4 Optical Fiber Current Sensing
References
9 Optical Fiber Sensors Based on the SMS Structure
9.1 Theory of SMS Fiber Structure
9.2 Characteristics of SMS Fiber Structure
9.3 Fiber Sensors Based on SMS Fiber Structure
References
10 Whisper‐Gallery‐Mode‐Based Hollow Microcavity Optical Fiber Sensing Technology
10.1 Whisper‐Gallery‐Mode Theory
10.2 Fabrication of Hollow Microcavity with Internal Air Pressure Control
10.3 Optical Fiber Magnetic Field Sensor Based on Thin‐Wall Micro‐Capillary and WGM
10.4 Optical Fiber High‐Resolution Temperature Sensor Based on Hollow Microsphere and WGM
10.5 Ultraprecise Resonance Wavelength Determination Method
References
Volume 2
Part II: Special Discrete Optical Fiber Sensing and Network
11 Optical Fiber Intra‐cavity Laser Gas Sensing Technology
11.1 Theory of Optical Fiber Intra‐cavity Laser Gas Sensing
11.2 Optical Fiber Intra‐cavity Laser Gas Sensing System Design
11.3 Spectrum Signal Process
11.4 Wavelength Calibration Analysis and Gas Recognition
References
12 Optical Fiber‐Based Optical Coherence Tomography
12.1 Optical Fiber Coherence Tomography Theory
12.2 Functional Optical Fiber‐Based Optical Coherence Tomography
12.3 Biomedical Applications
12.A The Detailed Matrix Elements of Mout
References
13 Discrete Optical Fiber Sensing Network Technology
13.1 Theory of Optical Fiber Sensing Network
13.2 Robustness Evaluation Model
13.3 Deployment Optimization for One‐Dimensional Optical Fiber Sensor Networks
13.4 A Self‐Healing Passive Fiber Bragg Grating Sensor Network
References
Part III: Distributed Optical Fiber Sensing
14 Distributed Vibration Sensing Based on Dual Mach–Zehnder Interferometer
14.1 Theory Analysis of Distributed Vibration Sensing Based on Dual Mach–Zehnder Interferometer
14.2 Polarization Control Method
14.3 Interferometer‐Based Distributed Vibration Sensing Instrument Design
14.4 Signal Process Algorithm and Instrument
References
15 Regional Style Intelligent Perimeter Security Technique Based on Michelson Interferometer
15.1 System Principle
15.2 Intrusion Detection Algorithm
15.3 Instrument Design
15.4 Perimeter Security Application
References
16 Distributed Temperature Sensing Based on Raman Scattering
16.1 Raman Scattering Theory
16.2 Principle of System
16.3 System Design
16.4 Temperature Demodulation Method
16.5 Denoising Algorithm
16.6 Main Technical Indicators of Sensors
References
17 Distributed Acoustic Sensing Based on Optical Time‐Domain Reflectometry
17.1 Theory of Optical Time‐Domain Reflectometry
17.2 Pulse Modulation Method
17.3 Acoustic Sensitivity Enhance Method of Optical Fiber
17.4 Dual‐Pulse Coherent Phase Optical Time‐Domain Reflectometry
17.5 Linear‐Frequency‐Modulation Pulse Phase Optical Time‐Domain Reflectometry
References
18 Distributed Sensing Based on Optical Frequency‐Domain Reflectometry
18.1 Principle of Optical Frequency‐Domain Reflectometry
18.2 Measurement Range OFDR Beyond Laser Coherence Length
18.3 Laser Frequency Tuning Nonlinearity and Compensation
18.4 Distributed Sensing System and Application
18.A Detail Derivation of
τ
ref
Estimation
18.B Detail Derivation of
τ
ref
Estimation by Higher-Order Taylor Expansion
References
19 Distributed Sensing Based on Brillouin Optical Correlation‐Domain Analysis
19.1 Theory of BOCDA Based on Stimulated Brillouin Scattering
19.2 Frequency‐Modulation Systems by Periodic Sinusoidal Waveforms
19.3 Phase‐Modulation Systems by High‐Rate Binary Sequences
19.4 High‐Resolution Long‐Range Chaotic Laser Sensors
References
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 A comparison of typical features between the EDFA and the SOA.
Chapter 2
Table 2.1 Physical parameters of alumina ceramic tube for packaging.
Table 2.2 Ambient temperatures of different devices.
Table 2.3 Location arrangement of sensors.
Table 2.4 Demodulation results under different SNRs of HCN absorption spectr...
Table 2.5 The standard deviation of demodulation wavelength.
Table 2.6 Bonding property at cryogenic temperature.
Chapter 3
Table 3.1 Quantitative linearity comparison table.
Table 3.2 Measurement error of the proposed method.
Chapter 4
Table 4.1 Results of light source SN60019244 stability test.
Table 4.2 Results of light source SN60019065 stability test.
Table 4.3 Birefringence parameters of MgF
2
crystal in the infrared spectral ...
Chapter 5
Table 5.1 Refractive index of sapphire at different wavelengths
n
i
(o). [5].
Chapter 6
Table 6.1 Performance of the MZIs‐based high‐temperature sensors.
Table 6.2 Performance of the MZIs‐based refractive index sensors.
Table 6.3 Performance of the MZIs‐based strain sensors.
Table 6.4 Performance of the FPIs‐based refractive index sensors.
Table 6.5 Performance of the FPIs‐based high‐temperature sensors.
Chapter 7
Table 7.1 Sensitivity, FWHM, and FOM of CPWR at different thickness for ZnO ...
Table 7.2 Sensitivity, FWHM, and FOM of CPWR at different film structures (S...
Table 7.3 Standard deviation of 50 groups of experiment data for the three m...
Chapter 8
Table 8.1 High crosstalk points in layers 1–4 of the first winding trial [51...
Table 8.2 Crosstalk comparison of layers 1–4 between the first and second wi...
Table 8.3 Polarization crosstalk in layers 1–2 with different winding tensio...
Table 8.4 Positions and lengths of every poles in the 350 m fiber coil [51].
Table 8.5 Polarization crosstalk summary of two different types PMF coils.
Table 8.6 Height and length of each fiber layer [68].
Table 8.7 Measurement results of
γδT
and
of three fiber coils [68...
Table 8.8 The outer surface temperature, the final temperature gradient, and...
Chapter 10
Table 10.1 Measurement data of fabricated microbubble samples.
Table 10.2 Parameters of five sensors.
Table 10.3 Comparisons of different optical fiber sensors developed for ocea...
Chapter 12
Table 12.1 Summary of different PS‐OCT configurations [38].
Chapter 13
Table 13.1 Calculations of ring topology OFSN robustness evaluation [3].
Table 13.2 Robustness of different topologies [3].
Table 13.3 Intensities of optical signals under all network statuses (
N
= 4)...
Chapter 14
Table 14.1 The positioning error of different regions.
Table 14.2 Recognition results of four typical patterns by using different k...
Chapter 15
Table 15.1 Statics on the number of false alarms between the algorithms.
Table 15.2 Experimental results of single defense zone.
Table 15.3 Experimental results.
Chapter 16
Table 16.1 Key device parameters of the RDTS.
Table 16.2 The repeatability of the system (°C).
Chapter 17
Table 17.1 Measurement result of a practical 3 × 3 fiber coupler.
Chapter 18
Table 18.1 Performance summary of software algorithms and short tuning range...
List of Illustrations
Chapter 1
Figure 1.1 Cross‐section refractive index profile of typical optical fiber....
Figure 1.2 Scheme of special optical fibers: (a) NCF, (b) TCF, (c) PMF, and ...
Figure 1.3 Spectrum of a combined SLDs light source.
Figure 1.4 Photo of a benchtop SLD light source.
Figure 1.5 Photo of OEM light source with two pigtailed DFB lasers.
Figure 1.6 Schematic diagrams of the optical fiber lasers with (a) linear ca...
Figure 1.7 Typical ASE spectrum of an EDF.
Figure 1.8 Scheme of a tunable fiber ring laser based on OMZI.
Figure 1.9 Green fluorescence of EDF pumped by 980 nm light.
Figure 1.10 The pertinent energy diagram of Er
3+
.
Figure 1.11 Schematic diagrams of EDFA with three optical pumping methods: (...
Figure 1.12 Photos of (a) a benchtop EDFA and (b) a modular EDFA.
Figure 1.13 Schematic diagram of SOA.
Figure 1.14 Wavelength responses of Si‐ and InGaAs‐based photodiodes.
Figure 1.15 Photos of (a) a Si‐amplified photodetector with space coupling i...
Figure 1.16 TO can pigtailed photodiode and its use in a demodulation circui...
Figure 1.17 Coupler port configuration. (a) Y‐coupler (b) optical fiber spli...
Figure 1.18 (a) Schematic diagram and (b) photo of 2 × 2 optical fiber coupl...
Figure 1.19 Schematic diagram of (a) Faraday magneto‐optical effect and (b) ...
Figure 1.20 (a) Schematic diagram of optical fiber polarization‐independent ...
Figure 1.21 (a) Schematic diagram and (b) photo of 2 × 2 optical fiber isola...
Figure 1.22 (a) Schematic of three‐port optical fiber circulator, (b) optica...
Figure 1.23 (a) Schematic diagram and (b) photo of optical fiber circulator ...
Figure 1.24 Mechanical optical fiber switchers based on (a) magnet and (b) r...
Figure 1.25 MEMS
m
×
n
optical fiber switcher matrix.
Figure 1.26 Electro‐optical fiber switcher (a) structure and (b) numerical c...
Figure 1.27 Schematic of 1 × 2 magneto‐optical fiber switcher. (a) Optical p...
Figure 1.28 Schematic of electro‐optical fiber modulator based on lithium ni...
Figure 1.29 MZI optical fiber intensity modulator.
Chapter 2
Figure 2.1 Ceramic tube package.
Figure 2.2 FBG temperature sensor packaged by ceramic tube: (a) single end a...
Figure 2.3 The package platform of FBG.
Figure 2.4 Schematic diagram of porcelain tube sealing with the low melting ...
Figure 2.5 FBG temperature sensor: (a) single‐end packaged FBG sensor and (b...
Figure 2.6 Schematic diagram of fiber grating strain sensor structure.
Figure 2.7 (a) Constant temperature heating table and (b) laser welding devi...
Figure 2.8 Photo of FBG strain sensor without glue package.
Figure 2.9 The wavelength (a), reflectivity (b), and reflection spectra (c) ...
Figure 2.10 The temperature during LN
2
experiment (a), the reflectivity of f...
Figure 2.11 The temperature (a), reflectivity variation (b), and wavelength ...
Figure 2.12 The strain test results: (a) strain change and (b) reflectivity ...
Figure 2.13 The wavelength shifts of WFBGs with different reflectivity from ...
Figure 2.14 (a) Linear thermal expansion of aluminum, copper, and Teflon nor...
Figure 2.15 (a) Schematic of experimental setup, (b) layout of space environ...
Figure 2.16 Wavelength variation (a) and amplitude change (b) of packaged se...
Figure 2.17 Ring cavity fiber laser distributed sensing demodulation system....
Figure 2.18 Schematic diagram of FBG sensing demodulation system based on lo...
Figure 2.19 Position relationship of F–P etalon, interferometer, and FBG....
Figure 2.20 Demodulation principle of half‐width of interference fringes....
Figure 2.21 Schematic diagram of the FBG demodulation system.
Figure 2.22 FBG demodulation system overall diagram.
Figure 2.23 Real photo of demodulator.
Figure 2.24 Experiment in thermal cycling process: operating temperature (a)...
Figure 2.25 Demodulation results at different operating temperature.
Figure 2.26 Demodulation results of different frequencies under increase in ...
Figure 2.27 Demodulation precision of seven FBGs and normalized absorption s...
Figure 2.28 The normalized HCN and FBG spectra collected by DAQ (a) and the ...
Figure 2.29 Schematic diagram of the FBG demodulation system with HCN gas ce...
Figure 2.30 Schematic diagram of convolution and deconvolution.
Figure 2.31 Comparison of HCN diagram spectrum at 60 °C.
Figure 2.32 Demodulated FBG wavelengths based on the detected HCN spectrum a...
Figure 2.33 Demodulated FBG wavelengths based on the detected HCN spectrum i...
Figure 2.34 (a) Spectrum of the output laser by OSA and (b) spectrum of the ...
Figure 2.35 (a) Original signals detected by PDs and (b) filtered and normal...
Figure 2.36 (a) Wavelength reference–sampling point calibration curve compar...
Figure 2.37 (a) Temperature change of the oven and (b) demodulation results ...
Figure 2.38 The microscope image of FBG1 (a) and FBG2 (d), the reflective sp...
Figure 2.39 (a) Wavelength shift of FBG sensors stuck to aluminum bar and ou...
Figure 2.40 The Bragg wavelength shift and measurement error of FBG3 (a), FB...
Figure 2.41 Study of the optical fiber loss at cryogenic temperature. (a) Sc...
Figure 2.42 WFBG sensor encapsulation and calibration: (a) images of customi...
Figure 2.43 WFBG sensor calibration: (a) wavelength vs. applied strain in LN
Figure 2.44 Schematic of the test platform for the cryogenic static test: (a...
Figure 2.45 The loading process of (a) axial force, F1 and F2 and (b) intern...
Figure 2.46 The strain measurement in the cryogenic static test: (a) hoop st...
Figure 2.47 The temperature variation during the test measured by “WFBG3” te...
Chapter 3
Figure 3.1 The theoretical model of multi‐beam interference.
Figure 3.2 The sensing model of fiber‐optic extrinsic Fabry–Pérot sensor....
Figure 3.3 The main configuration of IFPI sensors. (a) Both reflective surfa...
Figure 3.4 Schematic of the reflective film‐based IFPI sensor.
Figure 3.5 Schematic of the UV‐induced IFPI sensor.
Figure 3.6 Structure of the IFPI sensor with fusion splicing of different ki...
Figure 3.7 The main configuration of EFPI sensors. (a) EFPI composed of two ...
Figure 3.8 Construction of EFPI sensor based on aligned capillary.
Figure 3.9 The fabrication procedure of the EFPI based on SiO
2
diaphragm. (a...
Figure 3.10 Schematic diagram of the EFPI sensor based on air bubble.
Figure 3.11 The configuration of the EFPI fabricated by a near‐infrared femt...
Figure 3.12 The fabrication process of the EFPI sensor fabricated by a 157 n...
Figure 3.13 Schematic diagram of the EFPI sensor based on 45° angle‐polished...
Figure 3.14 Schematic diagram of the EFPI sensor based on sapphire wafer....
Figure 3.15 Schematic diagram of the EFPI sensor based on PVC cap.
Figure 3.16 Schematic diagram of the ILFPI sensor.
Figure 3.17 Configuration of the EFPI formed on the end of the optical fiber...
Figure 3.18 Configuration of the EFPI formed between a glass plate and a sil...
Figure 3.19 Configuration of the EFPI fabricated by Au–Au thermal‐compressio...
Figure 3.20 Schematic diagram of the proposed temperature and pressure dual‐...
Figure 3.21 (a) Part of through‐hole array in structured glass wafer, (b) pa...
Figure 3.22 Schematic diagram of the proposed all‐silicon‐based temperature ...
Figure 3.23 (a) Cross section of the all‐silicon sensing chip and (b) packag...
Figure 3.24 Measurement schematic of MEMS chip of fiber‐optic pressure senso...
Figure 3.25 (a) The diaphragm deformation schematic under high external and ...
Figure 3.26 Conceptual illustration of the relationship between cavity lengt...
Figure 3.27 The demodulation system structure diagram of polarization low‐co...
Figure 3.28 Miniaturized pressure demodulation instrument: (a) hierarchical ...
Figure 3.29 Interference pattern and amplitude envelopes drift as pressure v...
Figure 3.30 Conceptual illustration of amplitude–frequency and phase‐frequen...
Figure 3.31 Part amplitude–frequency characteristic curve obtained by DFT an...
Figure 3.32 Linearity comparison charts: (a) DFT serial number is 1548; (b) ...
Figure 3.33 Schematic diagram of the EFPI multiplexing system based on low‐c...
Figure 3.34 (a) Spectrum of LED light sources for the proposed method, (b) a...
Figure 3.35 (a) Relationship between the demodulated cavity length of three ...
Figure 3.36 Principle of multi‐channel optical fiber F–P demodulation device...
Figure 3.37 (a) The recovered EPPs of different channels with increasing air...
Figure 3.38 Schematic diagram of aircraft model (monitoring pressure at blac...
Chapter 4
Figure 4.1 (a) Sectional view and vertical view of fiber‐optic acoustic vibr...
Figure 4.2 Schematic diagram of the circumferential stretched diaphragm.
Figure 4.3 Variation of diaphragm resonance frequency with radius and preten...
Figure 4.4 Schematic diagram of dual‐wavelength phase extraction.
Figure 4.5 Simulation results of first‐level low‐coherence interference frin...
Figure 4.6 Simulation diagram of first‐level low‐coherence interference frin...
Figure 4.7 Theoretical model of refracted light interference of birefringent...
Figure 4.8 Schematic diagram of the dual‐laser quadrature phase demodulation...
Figure 4.9 Dual distributed Bragg feedback laser.
Figure 4.10 Schematic diagram of phase‐shifting demodulation instrument usin...
Figure 4.11 Spectrum of the light source used in the instrument.
Figure 4.12 Interference spectrum of the optical fiber F–P acoustic vibratio...
Figure 4.13 Photo of MgF
2
birefringent crystal, polarizer, and analyzer.
Figure 4.14 Photo of the demodulation system.
Figure 4.15 The specific demodulation system of fiber F–P sensor.
Figure 4.16 Schematic diagram of water listener monitoring.
Figure 4.17 Acoustic vibration signal during ice spraying.
Figure 4.18 Single vibration signal spectrum during ice spraying.
Figure 4.19 Schematic diagram of pressure tank experiment system.
Figure 4.20 Installation diagram of slide rail.
Figure 4.21 Response of optical fiber acoustic sensor and piezoelectric tran...
Figure 4.22 Response of optical fiber acoustic sensor and piezoelectric tran...
Figure 4.23 Response of optical fiber acoustic sensor and piezoelectric tran...
Chapter 5
Figure 5.1 Sapphire crystal transmittance.
Figure 5.2 Sapphire crystal cutaway.
Figure 5.3 Sapphire fiber transmission capacity and NA curve.
Figure 5.4 Sapphire wafer appearance.
Figure 5.5 Sapphire wafer topography. (a) The related parameters of the sapp...
Figure 5.6 Sensor structure diagram.
Figure 5.7 Fabry–Perot cavity beam transmission optical path diagram.
Figure 5.8 Interference fringe contrast vs. sapphire wafer thickness
L
and s...
Figure 5.9 Temperature sensitivity vs. wafer thickness.
Figure 5.10 Sapphire fiber and multimode fiber fusion effect diagram.
Figure 5.11 Beam transmission model of sapphire fiber and multimode fiber fu...
Figure 5.12 Optical power meter measures fiber splice loss.
Figure 5.13 Spectrometric measurement of fiber splice loss.
Figure 5.14 Fiber end face reflection spectrum signal diagram.
Figure 5.15 Schematic diagram of optical fiber high‐temperature sensor packa...
Figure 5.16 Photos of (a) sensor sample and (b) sensor metal outer tube pack...
Figure 5.17 Schematic diagram of the spectrum demodulation system.
Figure 5.18 Spectral demodulation system physical map.
Figure 5.19 (a) Interferometric spectral curves of different Fabry–Perot cav...
Figure 5.20 (a) Light source spectral distribution, (b) interferometric spec...
Figure 5.21 Actual interference spectrum signal diagram.
Figure 5.22 Interferogram of uniform distributed light source and Gaussian d...
Figure 5.23 Peak drift under Gaussian source distribution.
Figure 5.24 Output spectrum of Fabry–Perot cavity.
Figure 5.25 Fourier spectrum of interference spectrum signal.
Figure 5.26 Long spectrum curve drift of different Fabry–Perot cavities.
Figure 5.27 Schematic diagram of temperature shock test system.
Figure 5.28 High‐temperature shock experiment heating process diagram.
Figure 5.29 R
SN
= 20 dB interference spectrum signal simulation results: (a)...
Figure 5.30 Peak wavelength fluctuation under different SNR.
Figure 5.31 Peak wavelength fluctuations at different sapphire wafer thickne...
Figure 5.32 Different signal‐to‐noise ratios and interference level jumps un...
Figure 5.33 (a) Schematic of sensor head, (b) optical transmission path of s...
Figure 5.34 Schematic diagram of entire sensing system.
Figure 5.35 (a) Spectrums of two types of sensors in 1000 °C, (b) FFT of the...
Figure 5.36 (a) Measurement error of the two kinds of sensors after calibrat...
Figure 5.37 Fluctuation range of measured temperature results.
Chapter 6
Figure 6.1 Schematic diagram of optical fiber MI. OC: optical coupler.
Figure 6.2 The illuminations of assembly‐free MMIs on an SMF tip: (a) Step‐s...
Figure 6.3 (a) Experimental setup of the MI for high‐temperature sensing, (b...
Figure 6.4 Schematic diagram of fiber MZI. OC: optical coupler.
Figure 6.5 Schematic diagrams of assembly‐free fiber in‐line MZIs: (a) in‐li...
Figure 6.6 Schematic diagram of multiple‐beams interference in a Fabry–Perot...
Figure 6.7 (a) The multiple‐beam interference fringes with different reflect...
Figure 6.8 Multiple‐reflection model of two cascaded F–P cavities.
Figure 6.9 Schematic diagrams of assembly‐free fiber FPIs: (a) in‐line FPI b...
Chapter 7
Figure 7.1 A schematic representation showing the standard sputtering techni...
Figure 7.2 Scheme of thermal evaporation deposition.
Figure 7.3 (a) Parallel distribution structure and (b) star distribution str...
Figure 7.4 Schematic of the optical fiber CPWR sensor.
Figure 7.5 The transmission spectra of different polarizations and electric ...
Figure 7.6 Variations of the CPWR wavelengths with thickness of dielectric l...
Figure 7.7 (a) The transmission spectra of the sensor and (b) variations of ...
Figure 7.8 Variations of transmission spectra of the sensor with SRI when (a...
Figure 7.9 Variations of the first CPWR wavelength shift value with SRI in t...
Figure 7.10 The normalized transmitted spectra of the first CPWR mode for 10...
Figure 7.11 Variations of the first CPWR wavelength shift with SRI in the co...
Figure 7.12 Variations of the (a) resonance wavelength and (b) FWHM of the f...
Figure 7.13 (a) Schematic of the hetero‐core optical fiber SPR sensor and (b...
Figure 7.14 Experimental setup of the optical fiber SPR sensing system.
Figure 7.15 Variation of SPR resonance spectrum with refractive index for 50...
Figure 7.16 Variation of SPR resonance wavelength with refractive index when...
Figure 7.17 Optical fiber SPR temperature: (a) schematic configuration and (...
Figure 7.18 Schematic of optical fiber SPR temperature sensing system.
Figure 7.19 Normalized transmitted optical fiber‐based SPR spectrum at 60 °C...
Figure 7.20 Intrinsic mode functions and residue decomposed by EMD.
Figure 7.21 The filtered result with EMD method.
Figure 7.22 The conventional SPR spectrum for centroid algorithm and the inv...
Figure 7.23 The temperature vs. the corresponding resonance wavelength.
Chapter 8
Figure 8.1 Sagnac effect schematic diagram. (a) When the closed optical loop...
Figure 8.2 Typical structure of interferometric FOG, which consists of five ...
Figure 8.3 Output of the square wave bias modulation.
Figure 8.4 Polarization‐maintaining fiber types such as panda type, collar t...
Figure 8.5 Schematic diagram of four‐stage symmetric winding method, where A...
Figure 8.6 Schematic diagram of octagonal winding method, where A and B repr...
Figure 8.7 Schematic diagram of reverse octupole winding method, where A and...
Figure 8.8 Model of PM fiber polarization crosstalk.
Figure 8.9 Illustration of using a distributed polarization crosstalk analyz...
Figure 8.10 Polarization crosstalk of 1000 m raw fiber by two different manu...
Figure 8.11 Polarization crosstalk measurement results of layers 1–4 of the ...
Figure 8.12 The comparison of polarization crosstalk of layers 1–2 between w...
Figure 8.13 Marking locations of selected points on fiber by inducing tempor...
Figure 8.14 Polarization crosstalk curve of two different types of PMF coils...
Figure 8.15 Comparison of polarization crosstalk of PM coil after applying a...
Figure 8.16 Illustration of a quadrupole‐wound fiber coil [68]. (a) The rela...
Figure 8.17 Illustration of asymmetrical fiber wounding. (a) CCW (denoted by...
Figure 8.18 Gyroscopic setup for measuring thermal‐induced error signals. In...
Figure 8.19 (a) Measured rotation rate error (solid line) of a gyro system i...
Figure 8.20 (a) Illustration of coil trimming with two fiber turns unwrapped...
Figure 8.21 The pointing error taken before coil trimming. The lines indicat...
Figure 8.22 (a) Pointing error of Coil‐2 with different trimming lengths on ...
Figure 8.23 Illustration of different winding defects in a quadrupole wound ...
Figure 8.24 (a) Illustration of OCT image acquisition of a fiber coil. The f...
Figure 8.25 OCT tomographic image taken during the winding process of a four...
Figure 8.26 3D OCT images of a six‐layer fiber coil: (a) volumetric view of ...
Figure 8.27 All‐fiber current transformer based on Sagnac interferometer....
Chapter 9
Figure 9.1 Schematic diagram of an SMS fiber structure.
Figure 9.2 Power excitation efficiency of each mode.
Figure 9.3 Transmittance of the SMS as a function of
L
.
Figure 9.4 Transmission spectra of SMSs with four different reimaging
L'
Figure 9.5 Transmission spectrum of the SMS.
Figure 9.6 Reimaging peaks of SMS structures with different core radius.
Figure 9.7 Transmission spectra of SMS structures with different core radius...
Figure 9.8 Sensitivity vs. wavelength of two sensors in two different surrou...
Figure 9.9 Sensitivity change as a function of the surrounding RI.
Figure 9.10 RI response dependency on the characteristic wavelength.
Figure 9.11 RI response dependency on the radius of the NCF.
Figure 9.12 Microscopic images of the splicing joints between the SMF and an...
Figure 9.13 Schematic diagram of a typical experiment setup.
Figure 9.14 Measured spectra of the refractometers composed of different NCF...
Figure 9.15 Measured wavelength shift as a function of the characteristic wa...
Figure 9.16 RI calibration results: (a) transmission spectra of the sensor u...
Figure 9.17 Temperature calibration results: spectra of (a) dip 1 and (b) di...
Figure 9.18 RI change of distilled water as a function of temperature with a...
Figure 9.19 (a) Schematic diagram of a hybrid sensor constructed by cascadin...
Figure 9.20 (a) Schematic diagram of an SNS structure packaged with solution...
Figure 9.21 (a) Schematic diagram of the magnetic sensor based on MF and SNS...
Figure 9.22 (a) Measured transmission spectra of the SNS structure before an...
Figure 9.23 (a) Schematic diagrams of the straight and U‐bent sensor probes ...
Figure 9.24 (a) FLRD system incorporated with MF‐coated SNS structure, i.e. ...
Figure 9.25 (a) Schematic diagrams of the MF‐coated SP‐SMS sensor and its cr...
Figure 9.26 (a) Measured RTs varying upon the axis position of the three SP‐...
Figure 9.27 (a) Experimental setup for the magnetic field sensing. (b) and (...
Chapter 10
Figure 10.1 Schematic diagram of (a) WGM confinement with geometrical expres...
Figure 10.2 The model of micro‐capillary.
n
1
is the refractive index of core...
Figure 10.3 Calculated TM (
l
= 4
) electrical field distributio...
Figure 10.4 Electrical field distribution with radial mode number being
l =
...
Figure 10.5 Schematic diagram of the drawing system. PG, pressure gauge; OFT...
Figure 10.6 Photo of the drawing system. OFT, oxyhydrogen flame torch; HG, h...
Figure 10.7 Photos of the oxyhydrogen flame nozzles: (a) large diameter cera...
Figure 10.8 Schematic diagram of the cone shape of the fiber taper and the m...
Figure 10.9 Schematic diagram of pressure affection on expanding and shrinki...
Figure 10.10 (a) Waist outer radius of the micro‐capillary vs. the elongatio...
Figure 10.11 (a) Waist radius vs. the injection pressure of 30–85 kPa under ...
Figure 10.12 (a) Expansion velocity under the drawing length of 7000 μm and ...
Figure 10.13 Schematic diagram of the shape of micro‐capillary and microbubb...
Figure 10.14 The microscopic picture of the hollow microsphere.
Figure 10.15 Waist outer diameter increment vs. injection pressure of 60–120...
Figure 10.16 (a) Schematic diagram of Fe
3
O
4
coated with PEG. (b) Diagram of ...
Figure 10.17 Diagram of the distribution change of nanoparticles under an in...
Figure 10.18 A schematic illustration of the magnetic field sensor. The brow...
Figure 10.19 (a) Schematic diagram of the experimental setup for investigati...
Figure 10.20 (a) Transmission spectra of an empty capillary: the FSR is 5.47...
Figure 10.21 Transmission spectra of the sensor under magnetic‐field intensi...
Figure 10.22 WGM resonance wavelength vs. applied magnetic field: the proces...
Figure 10.23 Liner fit of the sensitivity in the linear region (from 0.073 t...
Figure 10.24 (a) Schematic diagram of the temperature sensor. (b) The micros...
Figure 10.25 (a) Schematic diagram of the temperature sensing measurements. ...
Figure 10.26 Transmission spectrum of the sensor from 10 to 11 °C, with the ...
Figure 10.27 (a) Resonant wavelength shift of five different sensors vs. tem...
Figure 10.28 The measured temperature sensitivities of the #3 hollow microsp...
Figure 10.29 The temperature variation during the 2 μl ethanol volatilizatio...
Figure 10.30 The scheme of ultraprecise resonance wavelength determination m...
Figure 10.31 (a) The dispersion of the capillary resonator. (b) The transmis...
Figure 10.32 (a) The red dashed line and blue solid line depict the relation...
Figure 10.33 The dotted curve is the ratio of FWHM between |
K
sin
ϕ
| and ...
Chapter 11
Figure 11.1 Schematic diagram of erbium ion level structure.
Figure 11.2 Schematic diagram of EDF ring laser system.
Figure 11.3 Laser output spectrum at different EDF lengths.
Figure 11.4 Laser output spectrum with different output spectral ratio.
Figure 11.5 Laser output spectrum at different pump power.
Figure 11.6 Laser output spectrum at different resonator losses.
Figure 11.7 The sensitivity enhancement factor changes with pump power in in...
Figure 11.8 The sensitivity enhancement factor changes with the total loss o...
Figure 11.9 The second harmonic spectrum in intra‐cavity gas sensing by wave...
Figure 11.10 The peak absorbance of absorption lines of CO
2
at different tem...
Figure 11.11 Schematic diagram of EDF ring cavity laser intra‐cavity gas sen...
Figure 11.12 Basic structure of EDFA.
Figure 11.13 The ASE spectrum of EDFA in (a) C‐band and (b) L‐band.
Figure 11.14 Schematic diagram of the working principle of F–P tunable filte...
Figure 11.15 The transmission spectrum of the F–P tunable filter under diffe...
Figure 11.16 Schematic diagram of gas cell structure design.
Figure 11.17 (a) The transmission spectrum of F–P etalon and (b) the reflect...
Figure 11.18 (a) The pure absorption spectrum of CO
2
and (b) the contaminate...
Figure 11.19 EMD results of the contaminated absorption spectrum of CO
2
. (a)...
Figure 11.20 The absorption spectrum of CO
2
after EMD denoising.
Figure 11.21 (a) The local absorption spectrum of CO
2
and (b) the second der...
Figure 11.22 (a) The baseline removal of the absorption spectral line of CO
2
Figure 11.23 Linetype fitting of spectral line absorbance distribution curve...
Figure 11.24 (a) The simulated overlapping absorption spectrum. (b) The reco...
Figure 11.25 The absorption spectral lines of (a) C
2
H
2
, (b) CO, and (c) CO
2
....
Figure 11.26 The sawtooth‐shaped voltage signal.
Figure 11.27 (a) The absorption spectrum of the mixed gas collected under no...
Figure 11.28 The concentration calibration lines of (a) C
2
H
2
, (b) CO, and (c...
Figure 11.29 The second harmonic spectrum of (a) C
2
H
2
, (b) CO, and (c) CO
2
i...
Figure 11.30 The concentration calibration lines of (a) C
2
H
2
, (b) CO, and (c...
Figure 11.31 The retrieved concentrations of (a) C
2
H
2
, (b) CO, and (c) CO
2
, ...
Figure 11.32 (a) The transmission spectrum of the spectrometer and (b) the t...
Figure 11.33 The relationship between the reflected light intensity of two F...
Figure 11.34 Wavelength calibration curve of scanning light source based on ...
Figure 11.35 The positioning result of absorption wavelength based on F–P et...
Chapter 12
Figure 12.1 Schematic of a generic time‐domain optical fiber‐based OCT syste...
Figure 12.2 Schematic of the all‐fiber OCT system. SLD, superluminescent dio...
Figure 12.3 Schematic of a generic spectral‐domain OCT system.
Figure 12.4 Schematic of a generic sweep‐source OCT system.
Figure 12.5 (a) OCT image and (b) DOCT image of
in vivo
rat kidney. The dash...
Figure 12.6 The scheme of sweep‐source PS‐OCT with PM fiber using single inp...
Figure 12.7 SMF‐based PS‐OCT schematic with a single IPS. SS, swept laser so...
Figure 12.8 (a–c) Images of human foot nail, (d–f) human finger nail fold, (...
Figure 12.9 Schematic diagram of a fiber‐based PS‐OCT with two different inp...
Figure 12.10 Schematic diagram of a fiber‐based PS‐OCT with two different in...
Figure 12.11 (a–d) Images of chicken breast muscle; (e–h) images of chicken ...
Figure 12.12 Photography of
ex vivo
human teeth. The red box includes enamel...
Figure 12.13 Two‐dimensional image of tooth crown structural. (a) Location 1...
Figure 12.14 Two‐dimensional image of enamel–dentin boundary on the side of
Figure 12.15 Three‐dimensional reconstructed OCT image of
ex vivo
human teet...
Figure 12.16 (a) Photograph of the imaging catheter and motion controller an...
Figure 12.17 Photograph of the system without the imaging catheter [114]....
Figure 12.18 Structure images of
in vivo
porcine cardiac blood vessel using ...
Figure 12.19 Images of
ex vivo
porcine cardiac blood vessel: (a) structure i...
Figure 12.20 (a) Photograph of
in vivo
animal experiments and (b) the spinal...
Figure 12.21 Intensity images and polarization contrast images of spinal str...
Figure 12.22 Intensity images and polarization contrast images of spinal str...
Figure 12.23 (a) Photograph of a coronal plane of a mouse brain; ROI is indi...
Chapter 13
Figure 13.1 Structure of discrete optical fiber sensor network.
Figure 13.2 Structure of distributed optical fiber sensor network.
Figure 13.3 Line topology for optical fiber sensors.
S
1
–
S
n
are optical fiber...
Figure 13.4 Ring topology for optical fiber sensors.
S
1
–
S
n
are optical fiber...
Figure 13.5 Star topology for optical fiber sensors.
S
1
–
S
n
are optical fiber...
Figure 13.6 Bus topology for optical fiber sensors.
S
1
–
S
n
are optical fiber ...
Figure 13.7 Robustness of ring, line, bus, and star topology networks, with ...
Figure 13.8 Robustness of ring, line, bus, and star topology networks, with ...
Figure 13.9 Robustness vs. number of sensors of ring topology network. (a)
α
...
Figure 13.10 Simulation condition for OFSN robustness assessment [3].
Figure 13.11 Flowchart of robustness assessment [3].
Figure 13.12 Experimental setup: light source is composed of an ASE broadban...
Figure 13.13 Sensors (green points) and target points (blue points) distribu...
Figure 13.14 Four topologies utilized in robustness experiment: (a) line top...
Figure 13.15 Experimental robustness of four topologies OFSNs (black) and si...
Figure 13.16 Comparison of experimental robustness for four OFSN topologies:...
Figure 13.17 One‐dimensional OFSN with four different types of optical fiber...
Figure 13.18 Sensor number (blue) and the OFSN robustness (red) under differ...
Figure 13.19 Effective monitoring area as sensor distance varies from 20 to ...
Figure 13.20 Relationship of optimum distance with two important parameters,...
Figure 13.21 Robustness vs. sensor distance. (a) Robustness with shifting se...
Figure 13.22 Simulation of an OFSN containing three identical sensors [4]....
Figure 13.23 Robustness and distance
d
23
under different
d
12
.
d
12
and
d
23
re...
Figure 13.24 One‐dimensional OFSN deployment scheme [4].
Figure 13.25 FBG sensor system for attenuation coefficient experiment [4]....
Figure 13.26 Four different sensor deployment schemes. (a) Scheme 1: Setting...
Figure 13.27 Robustness of Schemes 1–4 with increasing monitoring length [4]...
Figure 13.28 Robustness of Schemes 1, 2, and 4 with the increase in neighbor...
Figure 13.29 (a) A schematic of the star–ring FBG SN assembled with couplers...
Figure 13.30 Schematic of RN
i
,
i
= 1, …,
N
[5].
Figure 13.31 Single link failures in the star–ring fiber SN. (a) Single link...
Figure 13.32 Two link failures in the star–ring fiber SN. (a) Es
1
and Es
N
ar...
Figure 13.33 Three link failures in the star–ring fiber SN. (a) Es
1
, Es
2
, an...
Figure 13.34 The FBG SN used in the experiment [5].
Figure 13.35 The output spectrum when there is no fiber fault in the network...
Figure 13.36 (a) Network status 14. (b) The spectrum of
S
1
for network statu...
Figure 13.37 (a) Network status 10. (b) The spectrum of
S
1
for network statu...
Figure 13.38 (a) Network status 4. (b) The spectrum of
S
1
for network status...
Figure 13.39 Amount of wavelength shift for different network statuses [5]....
Figure 13.40 (a) The schematic diagram of the star–ring fiber sensor network...
Figure 13.41 Intensities of optical signals with different values of
a
[6]....
Figure 13.42 The FBG system used in the experiment [6].
Figure 13.43 (a) The network status 14. (b) The spectrum of
S
1
under the net...
Figure 13.44 (a) The network status 10. (b) The spectrum of
S
1
under the net...
Figure 13.45 (a) The network status 4. (b) The spectrum of
S
1
under the netw...
Figure 13.46 The experimental data and theoretical data [6].
Chapter 14
Figure 14.1 Schematic diagram of optical fiber is subjected to external forc...
Figure 14.2 Schematic diagram of classical Mach–Zehnder interferometer.
Figure 14.3 The sensitivity changed with the phase difference between the tw...
Figure 14.4 Configuration of the DMZI‐based vibration sensing system.
Figure 14.5 The equivalent optical path of the DMZI‐based vibration sensing ...
Figure 14.6 The relationship between the interference visibility and
τ
/
Figure 14.7 The relationship between the interference intensity and the phas...
Figure 14.8 Equivalent birefringence network of the DMZI‐based vibration sen...
Figure 14.9 Waveforms of two signals when polarization phase shift occurs....
Figure 14.10 The relationship curve between the equivalent SNR and the maxim...
Figure 14.11 Relationship between cross‐correlation positioning error and th...
Figure 14.12 Change of cross‐correlation positioning error with theoretical ...
Figure 14.13 Equivalent birefringence network of the single MZI.
Figure 14.14 Equivalent birefringence network of (a) the DMZI‐based vibratio...
Figure 14.15 DMZI‐based vibration sensor and its corresponding polarization ...
Figure 14.16 Flowchart of chaos particle swarm optimization algorithm for po...
Figure 14.17 Flowchart of genetic algorithm for polarization control.
Figure 14.18 Flowchart of the annealing algorithm for polarization control....
Figure 14.19 Overall structure of DMZI‐based distributed optical fiber vibra...
Figure 14.20 Software design flowchart of DMZI‐based distributed optical fib...
Figure 14.21 Software interface based on LabVIEW.
Figure 14.22 The frequency spectrum of the undisturbed signal.
Figure 14.23 Frequency response curve of all‐phase high‐pass filter.
Figure 14.24 (a) The input signal waveform curve of the filter and endpoints...
Figure 14.25 (a) The no‐intrusion signal, (b) the fence climbing signal, and...
Figure 14.26 Flowchart of the high‐precision positioning algorithm based on ...
Figure 14.27 Time–frequency spectrum of the fence climbing signal.
Figure 14.28 The fence climbing event in the experiment.
Figure 14.29 The fence climbing event and its ZCR distribution: (a) time‐dom...
Figure 14.30 Flowchart of the intelligent event recognition algorithm.
Figure 14.31 Architecture of the support vector machine.
Figure 14.32 Four typical vibration sensing event.
Chapter 15
Figure 15.1 Schematic diagram of Michelson interferometer‐based vibration se...
Figure 15.2 The schematic of the Michelson interferometer‐based vibration se...
Figure 15.3 Architecture of the Faraday rotator mirror.
Figure 15.4 The human intrusion signal.
Figure 15.5 The interference output with no intrusion.
Figure 15.6 The interference output with slight disturbance.
Figure 15.7 The interference output with wind disturbance.
Figure 15.8 The interference output with normal intensity rainfall.
Figure 15.9 The interference output with rainstorm disturbance.
Figure 15.10 Flowchart of fast intrusion detection method based on time‐doma...
Figure 15.11 Statistical indication of the threshold crossing rate of a fram...
Figure 15.12 The threshold crossing rate of each frame for the windy disturb...
Figure 15.13 The alarm frames of the sensing signal in the slight disturbanc...
Figure 15.14 The
T
2
value of the normal intensity raining signal.
Figure 15.15 (a) A segment signal of the rain disturbance signal. (b) The pr...
Figure 15.16 The threshold crossing rates of the various disturbance events....
Figure 15.17 The distribution of the number of alarm frames under different ...
Figure 15.18 The coefficients of the difference of each group under the rain...
Figure 15.19 Flowchart of the improved algorithm.
Figure 15.20 The overall schematic diagram of the Michelson interferometer‐b...
Figure 15.21 The modules of the perimeter security sensing system.
Figure 15.22 The circuit board of the vibration sensing system.
Figure 15.23 The overall chassis of the regional perimeter security system....
Figure 15.24 The main interface of the sensing system.
Figure 15.25 Flowchart of the software interface.
Figure 15.26 The experimental setup.
Figure 15.27 The working state of the sensing system with no intrusion event...
Figure 15.28 The working state of the sensing system with intrusion events a...
Chapter 16
Figure 16.1 Schematic diagram of typical backscatter in an optical fiber....
Figure 16.2 Schematic diagram of scattering energy level structure.
Figure 16.3 The working principle diagram of OTDR technology.
Figure 16.4 Experimental setup of RDTS. WDM, wavelength division multiplexer...
Figure 16.5 The single‐end demodulation experimental setup with Stokes demod...
Figure 16.6 The experiment results of FUT with anti‐Stokes self‐demodulation...
Figure 16.7 The single‐end demodulation experimental setup with anti‐Stokes ...
Figure 16.8 The experiment results of FUT with Stokes demodulate anti‐Stokes...
Figure 16.9 The loop configuration with reference fiber.
Figure 16.10 The sensing fiber distribution in the temperature experiment....
Figure 16.11 The overall distribution of the temperature measurement results...
Figure 16.12 Temperature demodulation results in the (a) single‐ended config...
Figure 16.13 Raman anti‐Stokes backscattering intensity.
Figure 16.14 Experimental setup of RDTS based on self‐demodulation method....
Figure 16.15 The fluctuation of ground noise of optical receiver.
Figure 16.16 Measurement results by using dynamic ground noise and constant ...
Figure 16.17 The results demodulated by origin signal and the signal after w...
Figure 16.18 Results of the self‐demodulation method at different test zones...
Chapter 17
Figure 17.1 Captured backscattering light.
Figure 17.2 Received electrical field signal composition. (Upper part adopts...
Figure 17.3 Direct‐detection‐based DAS system typical configuration: (a) Mac...
Figure 17.4 The interference signal electrical field composition.
Figure 17.5 Coherent‐detection‐based DAS system typical configuration.
Figure 17.6 Electronic schematic of a balanced detection circuit.
Figure 17.7 (a) AOM working principle and (b) physical photo.
Figure 17.8 (a) DPMZM schematic diagram. MZM, Mach–Zehnder modulator;
PM
,
ph
...
Figure 17.9 DSHM frequency spectrum detected with homodyne interference.
Figure 17.10 Acoustic sensitivity enhance method with thin‐wall corrugated e...
Figure 17.11 Acoustic sensitivity enhance method with polystyrene membrane: ...
Figure 17.12 (a) Quasi‐dual‐pulse scheme and (b) dual‐pulse scheme and its p...
Figure 17.13 (a) System configuration, (b) dual pulse, and (c) RBS signal fr...
Figure 17.14 Hybrid computation flow diagram.
Figure 17.15 (a) 3D plot of spatial‐temporal domain retrieved result from 10...
Figure 17.16 (a) Orthogonal phase code dual‐pulse scheme and (b) system conf...
Figure 17.17 Digital orthogonal phase code dual‐pulse computation flow.
Figure 17.18 (a) 3D plot of spatial‐temporal domain retrieved result of AM s...
Figure 17.19 Six‐port optical hybrid schematic diagram.
Figure 17.20 Virtual‐dual‐pulse‐distributed acoustic sensing: (a) principle ...
Figure 17.21 (a) The retrieved waveform temporal domain curve at 1050 m from...
Figure 17.22 Scheme for static measurement with step frequency scanning and ...
Figure 17.23 Scheme for dynamic measurement with linear‐frequency scanning: ...
Figure 17.24 Frequency shift generation scheme with LFM (chirped) pulse.
Figure 17.25 System configuration. PM, polarization maintaining; AWG, arbitr...
Figure 17.26 Discrete model of digital LFM pulse in the fiber.
Figure 17.27 Time‐domain envelopes comparison for PZT wrapped with 10 m SMF:...
Figure 17.28 Time‐domain envelopes comparison for 9 cm SMF: (a) and (b) are ...
Figure 17.29 Correlation coefficient of direct and coherent detection.
Figure 17.30 Three‐moment time‐domain envelope diagrams of four event length...
Figure 17.31 Schematic illustration of dual‐sideband mirrored LFM pulse. (a)...
Figure 17.32 (a) Time‐domain envelopes of upper sideband, (b) detail of (a),...
Figure 17.33 (a) Reconstructed original waveforms of two sidebands and diffe...
Figure 17.34 Schematic illustration of virtual‐block‐array phase analysis....
Figure 17.35 Experimental results: (a) comparison of the DP and the modulo D...
Figure 17.36 Schematic diagram of a dual‐LFM‐pulse and WFBGs array system....
Figure 17.37 The raw beat frequency signal at 2 km: (a) 3D spatial‐temporal ...
Figure 17.38 The raw beat frequency signal and phase demodulation results at...
Chapter 18
Figure 18.1 (a) OFDR basic configuration and (b) linearly tuning optical fre...
Figure 18.2 Experiment setup of an OFDR using a modified Mach–Zehnder interf...
Figure 18.3 (a–c) Measured Rayleigh backscattering and far‐end Fresnel refle...
Figure 18.4 Measured Rayleigh backscattering and far‐end Fresnel reflection ...
Figure 18.5 Beating signals are generated from the LO light and received lig...
Figure 18.6 Frequency‐sampling method for compensation of nonlinear phase no...
Figure 18.7 Software algorithms for compensation of the nonlinear phase nois...
Figure 18.8 Configuration for our OFDR system. The Mach–Zehnder auxiliary in...
Figure 18.9 Illustration of the NUFFT process. The solid circles are the ori...
Figure 18.10 (a) The experiment results for the auxiliary interferometer's o...
Figure 18.11 Comparison between main interferometer's beat signal for 51 m F...
Figure 18.12 Signal processing procedure of the nonlinear phase compensation...
Figure 18.13 Experimental setup of the OFDR system using deskew filter metho...
Figure 18.14 Measured Rayleigh backscattering and Fresnel reflections traces...
Figure 18.15 Illustration of the vibration position and frequency measuremen...
Figure 18.16 Analyzed cross‐correlation between local RBs in the non‐vibrate...
Figure 18.17 Measured distributed “non‐similar level” as a function of fiber...
Figure 18.18 Analysis of the cross‐correlation between the local RB non‐vibr...
Figure 18.19 Measured distributed “non‐similarity level” as a function of an...
Figure 18.20 (a) Measured distributed “non‐similarity levels” as a function ...
Figure 18.21 Measured distributed local RBS shifts as a function of FUT leng...
Figure 18.22 Measured spatial Rayleigh backscattering trace. An obvious “V”‐...
Figure 18.23 Signal processing procedure of RBS shift‐based distributed sens...
Figure 18.24 Experimental setup for distributed strain and temperature discr...
Figure 18.25 Measured RBS shifts of the standard SMF at different strain var...
Figure 18.26 Measured RBS shifts of the RC SMF at different strain variation...
Figure 18.27 Distributed RBS shifts from 34 to 35 m using the RC SMF applied...
Figure 18.28 Measurement values of our proposed method with respect to the t...
Figure 18.29 Experimental setup for distributed magnetic field measurement. ...
Figure 18.30 Distributed magnetic intensity trace from 44.5 to 46 m where th...
Figure 18.31 RBS spectral shift vs. magnetic intensity, the slope of the cur...
Figure 18.32 Experimental setup for distributed RI sensor using tapered fibe...
Figure 18.33 Configuration of small‐scale fiber‐tapering device. The RC SMF ...
Figure 18.34 RI measurement based on the optical frequency shifts of the bac...
Figure 18.35 (a) Measured optical frequency shifts of the back‐reflection sp...
Figure 18.36 Distance–time mapping trace of RI variation in a diffusion proc...
Chapter 19
Figure 19.1 Experimental setup of the millimeter‐order spatial resolution BO...
Figure 19.2 Brillouin gain spectrum at each segment of different fibers in F...
Figure 19.3 Confirmation of millimeter‐resolution distributed strain measure...
Figure 19.4 Schematic of the differential measurement for BOCDA: PM, phase m...
Figure 19.5 Experimental setup of the BOCDA system with the double modulatio...
Figure 19.6 Measurement results of BGS and BFS along the FUT. (a, c) Local B...
Figure 19.7 Schematic view on the progress of the pump pulse and CW probe wa...
Figure 19.8 (a) Concatenation of 148 BGSs obtained from 148 CP's. (b) Distri...
Figure 19.9 Experimental setup of a BOCDA system with 5000 points/s high‐spe...
Figure 19.10 Fiber under test with five measurement points.
Figure 19.11 BGS (a) and BFS (b) measured at five points selected arbitraril...
Figure 19.12 The principle of random‐access distributed fiber‐optic sensing ...
Figure 19.13 Experimental setup for random access SBS‐based distributed sens...
Figure 19.14 Brillouin gain mapping of a FUT, comprised of a 1 cm long secti...
Figure 19.15 Simulated magnitude of the acoustic wave density fluctuations (...
Figure 19.16 (a) Experimental setup for optimal time‐gated phase‐coded BOCDA...
Figure 19.17 Application of incoherent sequence compression to phase‐coded B...
Figure 19.18 (a) Measured Brillouin gain of the output signal wave (in arbit...
Figure 19.19 (a) An example of a single pair of output signal traces at BFS ...
Figure 19.20 Autocorrelation trace of the chaotic laser.
Figure 19.21 Experiment setup of proof‐of‐concept chaotic BOCDA.
Figure 19.22 (a) BGS distribution along the FUT and (b) BFS distribution alo...
Figure 19.23 The distribution map of correlation coefficient at
τ
d
= 11...
Figure 19.24 The BGS corresponding to the above operation points: (a) O, (b)...
Figure 19.25 (a) Measured BGS distribution along the FUT and (b) BFS distrib...
Figure 19.26 The waveforms (a) and the autocorrelation characteristics (b) o...
Figure 19.27 Experimental setup of the time‐gated chaotic BOCDA system. PC1,...
Figure 19.28 The BGSs of the chaotic BOCDA systems with (red) and without (b...
Figure 19.29 Measured distributions of the BGS (a) and BFS (b) along the FUT...
Figure 19.30 The typical status of chaos in the bandwidth adjustment process...
Figure 19.31 The map of BFS distribution along the FUT with the tensile stra...
Figure 19.32 Measured distributions of the BGS (a) and BFS (b) along the FUT...
Guide
Cover
Table of Contents
Title Page
Title Page
Copyright
Preface
Begin Reading
Index
WILEY END USER LICENSE AGREEMENT
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