Phase-sensitive OTDR system based on digital coherent detection

Pan, Zhengqing; Liang, Kezhen; Ye, Qing; Cai, Haiwen; Qu, Ronghui; Fang, Zujie

doi:10.1364/acp.2011.83110s

Cited by 56 publications

(22 citation statements)

References 6 publications

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“…The output beat signal is digitized using a 8-bit data-acquisition card with 3Gs/s sampling rate. The phase demodulation process is performed in the computer [8]. To illustrate the method, we introduce a sinusoidal vibration to the fiber via modulating a PZT located near 600m.…”

Section: Experiments and Analysismentioning

confidence: 99%

“…As the result of opposite interference, the envelops of beat are totally 10 different between neighbouring sampling period, as shown in Fig.1 (b). By performing the Fourier integral and calculating the differential phase (with detection aperture of 10m) [8], the amplitude and phase difference corresponding to each beat sequence can be independently extracted easily. Fig.2 (a) and (b) show the 400 consecutive superimposed traces of amplitude and phase difference calculated from each sequence of beat signals respectively.…”

Section: Experiments and Analysismentioning

confidence: 99%

“…Recently, we proposed a direct phase-demodulated Φ-OTDR based on digital coherent detection [8]. With the heterodyne detection, the instantaneous electric field of Rayleigh scattering light along the whole fiber can be obtained by analyzing the beat signal in software.…”

Section: Introductionmentioning

confidence: 99%

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Interference-fading-free phase-demodulated OTDR system

et al. 2012

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A phase-shifted double pulse method is proposed to reduce the influence of inner-pulse interference induced fading on phase demodulation of the Φ-OTDR. The feasibility of the technique is experimentally verified and the measurement resolution of the Φ-OTDR is minimized to as low as 0.1rad by using this technique. The experimental system demonstrates a distributed phase monitoring capability over 4km range with SNR of >20 and detection bandwidth of >360Hz.

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Section: Experiments and Analysismentioning

confidence: 99%

Section: Experiments and Analysismentioning

confidence: 99%

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Interference-fading-free phase-demodulated OTDR system

et al. 2012

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“…On the other hand, the optical phase of RBS lightwave was introduced into vibration sensing, since the optical phase variation has a directly proportional relationship to the vibration amplitude [10]. There were some researches to obtain the phase signal of RBS lightwave through the interference among RBS lightwaves from different pulses or different positions [11]- [14].…”

Section: Introductionmentioning

confidence: 99%

Long-Range Distributed Vibration Sensing Based on Phase Extraction From Phase-Sensitive OTDR

et al. 2016

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Distributed fiber-optic vibration sensors based on phase-sensitive optical timedomain reflectometry (-OTDR) have found many applications in various fields. In this paper, we analyze the phase noise of -OTDR, which is the main limiting factor of the measurement range. We found that the laser phase noise and phase extraction error caused by the intensity noise in photodetection contribute to the total phase noise. By introducing a series of auxiliary weak reflection points along the fiber, we develop a phase-noise-compensated -OTDR and realize a long-range distributed vibration sensing based on the phase extraction. Furthermore, a statistical analysis was proposed to maintain the vibration measurement sensitivity along the whole fiber. In the experiment, vibrations at 30 km were measured with a linear response, which confirmed the validity of our proposed system.

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“…The wavelength dependent GD can be obtained using the phase-sensitive optical frequency domain reflectometry (OFDR) technique [7] (shown in Fig. 2), or other phase measurement schemes, such as phase-sensitive optical time domain reflectometry (OTDR) [8]. Filer et al investigated the impact of GDR on the signal-to-noise ratio (SNR) of an optical transmission system and they concluded that GDR must be minimized as it deteriorates dramatically the optical link performance [9].…”

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confidence: 99%