Abstract
Distributed fiber acoustic sensing (DAS) technology can continuously spatially detect disturbances along the sensing fiber over long distance in real time. It has many unique advantages, including, large coverage, high time-and-space resolution, convenient implementation, strong environment adaptability, etc. Nowadays, DAS becomes a versatile technology in many fields, such as, intrusion detection, railway transportation, seismology, structure health monitoring, etc. In this paper, the sensing principle and some common performance indexes are introduced, and a brief overview of recent DAS researches in Shanghai Institute of Optics and Fine Mechanics (SIOM) is presented. Some representative research advances are explained, including, quantitative demodulation, interference fading suppression, frequency response boost, high spatial resolution, and distributed multi-dimension localization. The engineering applications of DAS, carried out by SIOM and other groups, are summarized and reviewed. Finally, possible future directions are discussed and concluded. It is believed that, DAS has great development potential and application prospect.
Highlights
Distributed fiber acoustic sensing (DAS) technology is a newly developed sensing technology, which can continuously detect external physical field over long distance, with coherent Rayleigh backscattering of low-noise laser in common single-mode sensing fiber
The second stage started and the studied, including digital coherent phase demodulation [15], phase generated carrier (PGC) [16,17], quantitative Φ-OTDR was termed as DAS
In frequency-swept pulse (FSP) Φ-OTDR, the laser seed E0 is modulated into a chirp probe pulse, expressed as, Ep = E0 rect(t/τ)exp( j2π f0 t + jπKt2 )
Summary
Distributed fiber acoustic sensing (DAS) technology is a newly developed sensing technology, which can continuously detect external physical field (vibration, sound and temperature variation) over long distance, with coherent Rayleigh backscattering of low-noise laser in common single-mode sensing fiber. Since 2011 [15], some quantitative rebuilt, but only qualitatively detected During this period, Φ-OTDR was usually termed as distributed demodulation methods were studied, including digital coherent phase demodulation [15], phase vibration sensing (DVS) technology. The second stage started and the studied, including digital coherent phase demodulation [15], phase generated carrier (PGC) [16,17], quantitative Φ-OTDR was termed as DAS. The possible future development of DAS is concluded boldly, considering the current situation
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