Ultra-long high-sensitivity Φ-OTDR for high spatial resolution intrusion detection of pipelines

Peng, Fei; Wu, Han; Jia, Xin-Hong; Rao, Yunjiang; Wang, Zinan; Peng, Zheng-Pu

doi:10.1364/oe.22.013804

Cited by 355 publications

(136 citation statements)

References 8 publications

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“…5. It can be found that the power of the RS signal over the whole 49 km keeps relatively even by optimizing the power of pulse light and forward Raman pump [4], and the power difference of the fitting curve between the strongest and the weakest positions is less than 3 dB. To verify the vibration performance of this hybrid system, vibration measurement at the end of fiber is employed.…”

Section: Vibration Testmentioning

confidence: 99%

“…The main nonlinear effect has been demonstrated to be modulation instability, which comes earlier than stimulated Brillouin scattering (BS) with the growing of the launching power of the probe pulse [3]. But BS still has to be considered even the stimulated BS does not occur, especially when the direct detection is employed (the spontaneous BS and RS are detected simultaneously) [4]. As to other aspect, in many applications, like structure health monitoring (SHM), after the vibration or acoustic wave generated by the structure transforming, the static strain (<0.1 Hz) of the structure usually changes accordingly.…”

Section: Introductionmentioning

confidence: 99%

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A hybrid Φ/B-OTDR for simultaneous vibration and strain measurement

Peng

Cao

2016

Photonic Sens

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A hybrid phase-sensitive optical time domain reflectometry (Φ-OTDR) and Brillouin optical time domain reflectometry (B-OTDR) system which can realize simultaneous measurement of both dynamic vibration and static strain is proposed. Because the Rayleigh scattering light and spontaneous Brilliouin scattering light are naturally frequency-multiplexed, the heterodyne asynchronous demodulation of frequency shift keying (FSK) in optical fiber communications is utilized, and the demodulations of the two scattering signals are synchronized. In addition, the forward Raman amplification is introduced to the system, which not only makes up for the deficiency of spontaneous Brilliouin scattering based distributed fiber sensor, but also has the merit of the single end measurement of B-OTDR. The designed Φ/B-OTDR hybrid system has the sensing range of 49 km with 10 m spatial resolution. The vibration and strain experiments show that this hybrid system has great potential for use in long-distance structural health monitoring.

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Section: Vibration Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A hybrid Φ/B-OTDR for simultaneous vibration and strain measurement

Peng

Cao

2016

Photonic Sens

Self Cite

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“…Distributed fiber optic sensors are widely used for variety of applications such as structural health monitoring, perimeter and pipeline security, temperature, pressure, strain, and vibration measurements due to its lightweight, ease of installation, and immunity to electromagnetic fields [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. One of the modern forward-looking fiber optic techniques, the so-called phase-sensitive optical time-domain reflectometry (w-OTDR), enables detection of acoustical perturbations along sensing optical fibers of several kilometers length [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Fiber Laser for Phase-Sensitive Optical Time-Domain Reflectometry

Spirin¹,

López-Mercado²,

Mégret³

et al. 2018

Selected Topics on Optical Fiber Technologies and Applications

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We have designed a new fiber laser configuration with an injection-locked DFB laser applicable for phase-sensitive optical time-domain reflectometry. A low-loss fiber optical ring resonator (FORR) is used as a high finesse filter for the self-injection locking of the DFB (IL-DFB) laser. By varying the FORR fidelity, we have compared the DFB laser locking with FORR operating in the under-coupled, critically coupled, and over-coupled regimes. The critical coupling provides better frequency locking and superior narrowing of the laser linewidth. We have demonstrated that the locked DFB laser generates a single-frequency radiation with a linewidth less than 2.5 kHz if the FORR operates in the critically coupled regime. We have employed new IL-DFB laser configuration operating in the critical coupling regime for detection and localization of the perturbations in phase-sensitive OTDR system. The locked DFB laser with a narrow linewidth provides reliable long-distance monitoring of the perturbations measured through the moving differential processing algorithm. The IL-DFB laser delivers accurate localization of the vibrations with a frequency as low as~50 Hz at a distance of 9270 m providing the same signal-to-noise ratio that is achievable with an expensive ultra-narrow linewidth OEwaves laser (OE4020-155000-PA-00).

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“…Thus, the Φ-OTDR was successfully detection scheme [6,7]. The long-range Φ-OTDR for intrusion sensing is demonstrated with the assistance of Raman amplification [8]. The Φ-OTDR was also demonstrated for vibration sensing by adopting heterodyne coherent detection [9].…”

Section: Introductionmentioning

confidence: 99%

Study of Ф-OTDR stability for dynamic strain measurement in piezoelectric vibration

Ren

Chen

et al. 2016

Photonic Sens

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Abstract:In a phase-sensitive optical-time domain reflectometry (Φ-OTDR) system, the challenge for dynamic strain measurement lies in large intensity fluctuations from trace to trace. The intensity fluctuation caused by stochastic characteristics of Rayleigh backscattering sets detection limit for the minimum strength of vibration measurement and causes the large measurement uncertainty. Thus, a trace-to-trace correlation coefficient is introduced to quantify intensity fluctuation of Φ-OTDR traces and stability of the sensor system theoretically and experimentally. A novel approach of measuring dynamic strain induced by various driving voltages of lead zirconate titanate (PZT) in Φ-OTDR is also demonstrated. Piezoelectric vibration signals are evaluated through analyzing peak values of fast Fourier transform spectra at the fundamental frequency and high-order harmonics based on Bessel functions. High trace-to-trace correlation coefficients varying from 0.824 to 0.967 among 100 measurements are obtained in experimental results, showing the good stability of our sensor system, as well as small uncertainty of measured peak values.

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Ultra-long high-sensitivity Φ-OTDR for high spatial resolution intrusion detection of pipelines

Cited by 355 publications

References 8 publications

A hybrid Φ/B-OTDR for simultaneous vibration and strain measurement

A hybrid Φ/B-OTDR for simultaneous vibration and strain measurement

Fiber Laser for Phase-Sensitive Optical Time-Domain Reflectometry

Study of Ф-OTDR stability for dynamic strain measurement in piezoelectric vibration

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