Abstract

In this work, a new system is proposed for quasi-distributed vibration sensing based on the Doppler effect. The setup employs an optical frequency domain reflectometer (OFDR) and an array of weak reflectors. The short-time Fourier transform (STFT) is employed to obtain the spectrogram, then the demodulation process detects the frequency variation and compensates the accumulated response. In this manner, events occurring in the fiber segment between neighboring reflectors can be measured. The theoretical development of the approach is presented and demonstrated, evidencing the velocimeter operation of the technique. The setup has been proved in several tests under different perturbation conditions, evaluating the limitations and capabilities. This solution presents many advantages such as the ability to measure arbitrary perturbations, the linear response, high spatial-resolution, simplicity, high configurability or the low repetition rate required to detect kilohertz-frequency vibrations.

Quasi-distributed vibration sensing using OFDR and weak reflectors

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Opt. Lett. 44(8) 1884-1887 (2019)

Phase demodulation method based on a dual-identical-chirped-pulse and weak fiber Bragg gratings for quasi-distributed acoustic sensing

Guanhua Liang, Junfeng Jiang, Kun Liu, Shuang Wang, Tianhua Xu, Wenjie Chen, Zhe Ma, Zhenyang Ding, Xuezhi Zhang, Yongning Zhang, and Tiegen Liu
Photon. Res. 8(7) 1093-1099 (2020)

Large-scale multiplexed weak reflector array fabricated with a femtosecond laser for a fiber-optic quasi-distributed acoustic sensing system

Mengshi Wu, Chi Li, Xinyu Fan, Changrui Liao, and Zuyaun He
Opt. Lett. 45(13) 3685-3688 (2020)

Highly sensitive quasi-distributed fiber-optic acoustic sensing system by interrogating a weak reflector array

Mengshi Wu, Xinyu Fan, Qingwen Liu, and Zuyuan He
Opt. Lett. 43(15) 3594-3597 (2018)

Long-range and wide-band vibration sensing by using phase-sensitive OFDR to interrogate a weak reflector array

Zhaopeng Zhang, Xinyu Fan, and Zuyuan He
Opt. Express 28(12) 18387-18396 (2020)