Polarization-sensitive distributed perturbation sensing and measuring method and system

Abstract

The invention discloses a polarization-sensitive distributed perturbation sensing method and a polarization-sensitive distributed perturbation sensing system. The better embodiment of the polarization-sensitive distributed perturbation sensing system comprises a function generator (1), a pulse laser (2), a polarization controller (3), a circulator (4), a sensing optical fiber (5), a polarization beam splitter (6), a balanced amplification photoelectric converter (7), a data acquisition unit (8) and a data processing unit (9), wherein the intensity of two paths of optical signals of which the polarization directions are vertical mutually is subjected to substraction by the balanced amplification photoelectric converter so as to obtain the intensity difference reflecting the change of the polarization state of the two paths of optical signals; and data acquired by a data acquisition module is detailedly analyzed to realize the sensitive monitoring on optical perturbation signals. The method has the advantage of improving the detection sensitivity of the sensing system greatly.

Description

technical field [0001] The invention relates to an optical fiber sensing system, in particular to a polarization-sensitive distributed perturbation sensing method and system based on a polarization beam splitter and a balanced amplifying photoelectric converter. Background technique [0002] External extrusion, impact, vibration, etc. will cause disturbances in the optical fiber, and these perturbations will cause changes in the birefringence axis of the optical fiber and then cause changes in the polarization state of the optical signal transmitted in the optical fiber. The polarization-sensitive distributed micro-perturbation optical fiber sensing system uses the above-mentioned polarization state change characteristics to sense whether the optical fiber is disturbed by the outside world by analyzing the polarization state of the Rayleigh scattered light signal transmitted back in the optical fiber. [0003] In the prior art, there are many methods for measuring the polari...

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Problems solved by technology

[0003] In the prior art, there are many methods for measuring the polarization state of an optical signal, including the analyzer method and the method based on a polarization beam splitter and a double detector. The analyzer method is to measure the intensity of the optical signal passing through the analyzer Reflecting the change of the polarization state, this method cannot make full use of the energy of the measured optical signal; the method based on the polarization beam splitter and dual detectors is to use the polarization beam splitter to divide the measured optical signal into two optical signals perpendicular to each other. Then the two optical signals output by the polarization beam splitter are input to two photodetectors respectively, and then the data of the two signals are collected and processed separately. Although this method can make full use of the energy of the optical signal, it needs to use Two photodetectors have a complex structure and a large amount of data, which requires a long time for data processing, resulting in a long response time of the system

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