Method for Reducing Polarization Fading of Optical Fiber Vibration System and Detection System Using It

Abstract

The present invention relates to the technical field of communication monitoring, more specifically, to a method for reducing the polarization fading of an optical fiber vibration system and a detection system using it, including: S10. Measure and record the length of the optical fiber, and form a reciprocating arrangement by welding the head and tail of the fiber core long-distance optical fiber; S20. The data collected by the data acquisition card is sent to the data processing program of the PC for phase extraction and calculation to obtain the phase change value; S30. according to the measured optical fiber length in the step S10, each fiber in the optical fiber The core position is mapped to the actual position of the optical fiber, and the point with the largest phase change value is taken as the actual signal; S40. If the phase change value exceeds the phase change threshold, it is determined as a vibration intrusion point, an alarm signal is sent, and the position of the vibration intrusion point is calculated; If the phase change value does not exceed the phase change threshold, it is determined that there is no vibration signal. The present invention greatly reduces the probability of polarization fading by using multiple points to simultaneously detect, thereby reducing the phenomenon of missed detection of intrusion signals caused by polarization fading.

Description

technical field [0001] The invention relates to the technical field of communication monitoring, more specifically, to a method for reducing polarization fading of an optical fiber vibration system and a detection system using the same. Background technique [0002] Distributed optical fiber vibration detection technology is more and more widely used in pipeline leak detection, pipeline anti-excavation and various perimeter security. However, the polarization fading in the optical fiber sensing system is caused by various reasons: (1) The polarization direction of the incident light incident on the optical fiber interference structure is randomly disturbed by changes in the ambient temperature; (2) inside the optical fiber interference structure, due to the random bending of the optical fiber The birefringence effect caused by , torsion and other effects affects the polarization state of the transmitted light, and these effects change with changes in external factors such as...

AI Technical Summary

Problems solved by technology

However, the polarization fading in the optical fiber sensing system is caused by various reasons: (1) The polarization direction of the incident light incident on the optical fiber interference structure is randomly disturbed by changes in the ambient temperature; (2) inside the optical fiber interference structure, due to the random bending of the optical fiber The birefringence effect caused by , torsion and other effects affects the polarization state of the transmitted light, and these effects change with changes in external factors such as ambient temperature and mechanical vibration.

The above-mentioned polarization fading leads to false alarms in distributed optical vibration detection instruments, which seriously restricts the development of distributed optical fiber vibration detection instruments.

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