Polarization-induced fading resisting alarming algorithm for optical fiber sensing signals

Abstract

The invention discloses a polarization-induced fading resisting method and an alarming algorithm for optical fiber bragg grating sensing signals. Firstly, interference signals reflected back by two adjacent fiber bragg gratings are received by using a tri-state polarization diversity receiver, and interference signals having an uncertain polarization state are divided into three paths and then aremodulated by a signal generator of a system to form three groups of phase-shifted light intensity signals of each path; then, the three groups of phase-shifted light intensity signals of each path are compared with each other in a sampling time period to solve the interference contrast of the three paths of phase-shifted light intensity signals, the path with the best contrast in the three pathsof phase-shifted light intensity signals is determined, and then the phase demodulation of the vibration of an optical fiber sensor is performed by combining a three-step phase shift algorithm; and then a discrete difference algorithm is used to process a phase signal sequence and set an alarm threshold value, and whether an alarm is sent or not is judged by counting the number of discrete difference signals exceeding the threshold value after the difference. The method for determining the contrast of the interference signals has high real-time performance and high accuracy; and the alarming algorithm has high dynamic signal change monitoring capability, high precision and high environmental interference resistance.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to an anti-polarization fading alarm algorithm for optical fiber sensing signals. Background technique [0002] In our country, with the in-depth implementation of the reform and opening up policy, the social wealth has increased rapidly, and the people's demand for safety is also getting higher and wider. Domestic perimeter security products will maintain a rapid development trend in recent years, with huge development potential. [0003] Compared with traditional electronic sensors, fiber optic sensors have many advantages such as small size, light weight, low cost, anti-electromagnetic interference, high sensitivity, safety and reliability, corrosion resistance, distributed measurement, and easy networking. Widely used in the measurement of temperature, vibration, stress and other parameters. [0004] In actual work, the signals received by the system ...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide an anti-polarization fading alarm algorithm for optical fiber sensing signals, which solves the shortcoming that the data acquisition module receives the weak interference light intensity signal output by the circulator, and realizes the acquisition of uncertain polarization state interference signals; Simplifies and implements an alarm algorithm with strong real-time performance, strong anti-environment interference ability and high accuracy

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