Phase Generation Carrier Modulation and Demodulation System of Optical Fiber Interferometric Sensor Against Polarization Fading

Abstract

The invention provides a phase generation and carrier modulation and demodulation system of an optical fiber interferometric sensor with polarization fading resistance. The system comprises a light source outputting frequency modulation light beams, a signal generator and a frequency multiplier for generating frequency modulation signals and dual frequency-doubling signals of a light source, a sensor composed of an unbalanced optical fiber interferometer, a three-way polarization diversity detection module for obtaining interference signals output by the interferometer in three polarization directions, a multi-channel A / D converter, and a digital signal processor for receiving output signals of the A / D converter and completing demodulation of detection signals of the sensor. Phase generation and carrier modulation and demodulation of the optical fiber interferometric sensor with the polarization fading phenomenon can be achieved, real-time demodulation treatment can be achieved, and the requirement for demodulation signal continuity can be met.

Description

technical field [0001] The invention relates to a signal demodulation technology of an interference optical fiber sensor, in particular to an anti-polarization fading optical fiber interference type sensor phase generation carrier modulation and demodulation system. Background technique [0002] The interferometric fiber optic sensor based on optical phase detection technology consists of a fiber optic interferometer. The measured physical quantity acts on the sensing arm of the sensor interferometer, causing a corresponding change in the phase of the transmitted light in the optical fiber of the sensing arm, and the reference arm optical fiber is insensitive to the measured physical quantity. The output light of the sensing arm and the reference arm interferes, and the phase change of the light is converted into the change of the interference light intensity, and the information of the measured physical quantity can be obtained by detecting the change of the light intensity...

AI Technical Summary

Problems solved by technology

In order to achieve stable demodulation, it is necessary to select the signal with the best signal-to-noise ratio in the same period among the n signals, so it is difficult to realize real-time processing of the demodulation method, and at the same time, there are breakpoints in the demodulated signal

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