Demodulation method for Bragg grating

Abstract

The invention relates to a demodulation method for a Bragg grating. The demodulation method for Bragg grating comprises the following steps: inputting broadband light into an F-P tunable filter by using an ASE broadband light source, converting the broadband light into frequency-sweeping narrowband light by using the F-P tunable filter under the action of scanning control periodic voltage provided by a digital signal processor (DSP) system, and changing the length of an F-P cavity in the filter by using an electrically controlled piezoelectric ceramic to change the conductive frequency band of the F-P filter; scanning the reflecting light spectrum of the whole grating by using the conductive frequency band of the F-P filter under the action of a tuning control signal, calculating the required current according to the current filter optical fiber grating temperature obtained by a PID controller, and setting the temperature of the filter optical fiber grating to the proper working point by setting the current of a current source; performing signal measurement on an optical fiber grating dynamic strain sensing system by using a computer through a program control data acquisition card after the system is stabilized at the working point, and measuring the strained dynamic signal by using the system in a self-triggering mode after a trigger signal appears; converting an optical signal into an electric signal by using a photoelectric detector and entering the DSP system; and adding an interpolant into a light path, and interpolating and calibrating the wavelength value. By the method, the signal to noise ratio is high and the strain measurable range is large.

Description

Technical field [0001] The present invention relates to the field of optical technology, in particular to a demodulation method of Bragg grating. Background technique [0002] Fiber Bragg Grating (FBG) is a new kind of basic optical fiber device with broad application prospects in optical fiber communication, optical fiber sensing and other optoelectronic processing fields. At present, the production and application research of FBG has become a hot spot and focus of optical fiber technology research in various countries in the world. As a sensing element, the fiber grating converts the sensed information into the movement of its reflection wavelength, that is, wavelength coding, so it is not affected by light source power fluctuations and system losses. In addition, fiber grating has the characteristics of good reliability, anti-electromagnetic interference, anti-corrosion, etc. It is easy to connect multiple fiber gratings in series on a fiber to form a fiber grating array to r...

AI Technical Summary

Problems solved by technology

This demodulation method has the characteristics of fast response and high resolution, and is mostly suitable for dynamic measurement. However, in the actual application process, it is extremely susceptible to interference from external factors such as strain and temperature.

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