Optical phase demodulation method and system based on polarization-division receiving

Abstract

The invention discloses an optical phase demodulation method and system based on polarization-division receiving. The method comprises the following methods that I / Q demodulation is carried out on optical signals collected by two sensing points, and signal polarization receiving is carried out by using a polarization receiving device to obtain corresponding signal components; an optical phase vector is constructed according to the corresponding signal components; a birefringence phase vector is determined according to the optical phase vector, and the phase difference is normalized; and afterthe birefringence phase vector is compensated, the phase change between the two sensing points is obtained through vector synthesis. According to the invention, a birefringence phase vector is compensated, so that the influence of polarization fading on signal demodulation is reduced, and the system stability is improved; and the I signal and the Q signal are subjected to orthogonal decomposition,and optical signals are converted into a vector to realize depolarized phase demodulation, so that the birefringence phase difference can be accurately estimated, and the accuracy of signal restoration is improved.

Description

technical field [0001] The invention belongs to the technical field of optical fiber distributed acoustic wave sensing, and more specifically relates to an optical phase demodulation method and system based on polarization polarization reception. Background technique [0002] Fiber-optic distributed acoustic wave sensing systems have received great attention in applications such as infrastructure health monitoring, oil reservoir exploration, and underwater sound detection due to their low cost per sensing point and easy deployment. Using the backscattering effect, the optical fiber distributed acoustic wave sensing system detects the intensity, phase and frequency of backscattered light to obtain acoustic information along the fiber. Among various sensing mechanisms, optical phase sensing has become the mainstream of fiber-optic distributed acoustic wave sensing systems with the highest sensitivity. Since distributed optical fiber sensing can realize the extraction of distr...

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Problems solved by technology

[0004] Aiming at the defects of the prior art, the purpose of the present invention is to provide an optical phase demodulation method and system based on polarization polarization reception, aiming at solving the phase noise caused by polarization fading in the existing optical fiber distributed sensing system, which leads to The problem of low system stability

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