A temperature self-compensation method for a temperature self-compensation high-resolution high-frequency fiber grating demodulation system

Abstract

The invention discloses a temperature self-compensation high-resolution high-frequency demodulation system and method for a fiber bragg grating. According the optical path transmission process, a tunable narrow-band laser device emits narrow-band light which is divided into two light beams through an optical fiber splitter, the two light beams are output through two output ports of the optical fiber splitter respectively, one light beam is transmitted to a sensing grating through the input end of a first optical fiber coupler and returns to the other input end of the first optical fiber coupler after passing through the sensing grating to be transmitted to a first photoelectric detector and be converted into a voltage signal, and then the voltage signal is transmitted to a data colleting and processing device; the other light beam is transmitted to a temperature compensation grating through a second optical fiber coupler and returns to the other input end of the second optical fiber coupler after passing through the temperature compensation grating to be transmitted to a second photoelectric detector and be converted into a voltage signal, and then temperature compensation is performed on the voltage signal through a temperature self-compensation device, so that the variable quantity of the output center wavelength of the tunable narrow-band laser device is obtained. The temperature self-compensation high-resolution high-frequency demodulation system and method have the advantages that temperature self-compensation is achieved, and the resolution is high.

Description

technical field [0001] The invention relates to a temperature self-compensating high-resolution high-frequency fiber grating demodulation system and method. Background technique [0002] With the increasing application of Fiber Bragg Grating (FBG) sensors in the field of acoustic emission, the demand for temperature self-compensation and high-resolution acoustic emission demodulation technology is increasingly urgent. Common demodulation techniques for fiber gratings include F-P filter method, edge filter method, and power demodulation method. F-P demodulation technology is mature, but its mature demodulation equipment is only up to 2000Hz, the application range is narrow, and it is difficult to meet the needs of acoustic emission high-resolution demodulation (the frequency range of acoustic emission signals is very wide, from several Hz sub-audio frequency, Ultrasonic frequencies from 20Hz to 20KHz to several MHz belong to the category of acoustic emission). Edge filterin...

AI Technical Summary

Problems solved by technology

The fiber grating sensor is sensitive to temperature, and the temperature change will easily lead to the drift of the wavelength of the grating, which will lead to the drift of the linear range of its reflection spectrum.

At the same time, the output wavelength of the tunable narrowband laser is relatively constant, causing its output wavelength to deviate from the linear range of the FBG reflection spectrum, reducing the demodulation accuracy

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