Interference Fading Elimination With Single Rectangular Pulse in $\Phi$-OTDR

Yu-hua, WU; Wang, Zinan; Xiong, Ji; Jiang, Jialin; Lin, Shengtao; Chen, Yong-Xiang

doi:10.1109/jlt.2019.2916682

Cited by 85 publications

(19 citation statements)

References 30 publications

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“…This processing method was also adopted by making use of the harmonics of optical intensity modulator [11]. Most recently, spectrum extraction and remix (SERM), as well as spectrum extraction and phase-shift transform methods have also been developed [12][13][14]. Essentially, all these reported solutions can be categorized as frequency-division multiplexed (FDM) methods.…”

Section: Introductionmentioning

confidence: 99%

Interference fading suppression in φ-OTDR using space-division multiplexed probes

Zhao

et al. 2021

Opt. Express

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We propose and experimentally demonstrate a novel interference fading suppression method for phase-sensitive optical time domain reflectometry (φ-OTDR) using space-division multiplexed (SDM) pulse probes in few-mode fiber. The SDM probes consist of multiple different modes, and three spatial modes (LP01, LP11a and LP11b) are used in this work for proof of concept. Firstly, the Rayleigh backscattering light of different modes is experimentally characterized, and it turns out that the waveforms of φ-OTDR traces of distinct modes are all different from each other. Thanks to the spatial difference of fading positions of distinct modes, multiple probes from spatially multiplexed modes can be used to suppress the interference fading in φ-OTDR. Then, the performances of the φ-OTDR systems using single probe and multiple probes are evaluated and compared. Specifically, statistical analysis shows that both fading probabilities over fiber length and time are reduced significantly by using multiple SDM probes, which verifies the significant performance improvement on fading suppression. The proposed novel interference fading suppression method does not require complicated frequency or phase modulation, which has the advantages of simplicity, good effectiveness and high reliability.

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Section: Introductionmentioning

confidence: 99%

Interference fading suppression in φ-OTDR using space-division multiplexed probes

Zhao

et al. 2021

Opt. Express

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“…A common way for further fading elimination is to aggregate K statistically independent channels. These channels can be obtained simply by spectrum extraction and remix method, only a single rectangular probe pulse is required [52]. For the selection of aggregate channel numbers, through theoretical calculations and experimental verification, the fading suppression shows rather efficient in the case of 4 to 10 aggregated channels [53].…”

Section: ф-Otdr With Coherent Detectionmentioning

confidence: 99%

Recent Advances in Phase-Sensitive Optical Time Domain Reflectometry (Ф-OTDR)

Rao

Wang

et al. 2021

Photonic Sens

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Phase-sensitive optical time domain reflectometry (Ф-OTDR) is an effective way to detect vibrations and acoustic waves with high sensitivity, by interrogating coherent Rayleigh backscattering light in sensing fiber. In particular, fiber-optic distributed acoustic sensing (DAS) based on the Ф-OTDR with phase demodulation has been extensively studied and widely used in intrusion detection, borehole seismic acquisition, structure health monitoring, etc., in recent years, with superior advantages such as long sensing range, fast response speed, wide sensing bandwidth, low operation cost and long service lifetime. Significant advances in research and development (R&D) of Ф-OTDR have been made since 2014. In this review, we present a historical review of Ф-OTDR and then summarize the recent progress of Ф-OTDR in the Fiber Optics Research Center (FORC) at University of Electronic Science and Technology of China (UESTC), which is the first group to carry out R&D of Ф-OTDR and invent ultra-sensitive DAS (uDAS) seismometer in China which is elected as one of the ten most significant technology advances of PetroChina in 2019. It can be seen that the Ф-OTDR/DAS technology is currently under its rapid development stage and would reach its climax in the next 5 years.

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“…To reduce the fading points as well as reserve the phase information, a method using spectrum extraction and rotated-vector-sum method is put forward as shown in Fig. 2 [14], which is simply called SERVS in this article.…”

Section: B the Suppression Of Interference Fading In Pulse-intensity-...mentioning

confidence: 99%

Interference-Fading-Suppressed Pulse-Coding Φ-OTDR Using Spectrum Extraction and Rotated-Vector-Sum Method

et al. 2021

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With phase-sensitive optical time-domain reflectometry (Φ-OTDR), an optic fiber can be used as a distributed vibration sensor to perceive the external disturbance along the fiber through the phase variation of the Rayleigh backscatter light. However, due to the inevitable interference fading phenomenon, the signal-tonoise ratio (SNR) of Rayleigh backscatter light at certain points is insufficient, thus affecting the fidelity of vibration sensing. In this paper, we propose the spectrum extraction and the rotatedvector-sum (SERVS) method to suppress the interference fading in the pulse-intensity-coding Φ-OTDR, which applies Golay complementary sequence through acousto-optic modulator (AOM). Benefited from the easier implementation, the experimental results demonstrate that the percentage of fading points can be reduced from 2.98% to 0.33% significantly and the standard deviation of differential phase is also decreased from 0.6556 rad to 0.2901 rad. Also the minimum level of averaged power spectral density (PSD) of the differential phase at whole locations along the fiber is reduced about 6 dB/Hz effectively. For the demodulated disturbance signal, no influence on the SNR is observed thus it maintains a SNR improvement of 8.6 dB compared to the traditional single pulse Φ-OTDR system, achieving a noise floor of 2.38 pε/ÝHz.

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Interference Fading Elimination With Single Rectangular Pulse in $\Phi$-OTDR

Cited by 85 publications

References 30 publications

Interference fading suppression in φ-OTDR using space-division multiplexed probes

Interference fading suppression in φ-OTDR using space-division multiplexed probes

Recent Advances in Phase-Sensitive Optical Time Domain Reflectometry (Ф-OTDR)

Interference-Fading-Suppressed Pulse-Coding Φ-OTDR Using Spectrum Extraction and Rotated-Vector-Sum Method

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