Fiber bragg grating sensing wavelength calibration device based on cavity absorption

Abstract

A fiber bragg grating sensing wavelength calibration device based on cavity absorption comprises an ASE light source, a coupler, an optical circulator, an optical grating array, an optical switch, a volume grating, a resonant cavity, an optical switch connecting end I and an optical switch connecting end II. The fiber bragg grating sensing wavelength calibration device based on cavity absorption is characterized in that the ASE light source is connected with the coupler, a port P1 of the coupler is connected with a port a of the optical circulator, a port b and a port c of the optical circulator are connected with the optical grating array and the optical switch connecting end I respectively, a port P2 of the coupler is connected with the resonant cavity, the resonant cavity is connected with the optical switch connecting end II, and the volume grating is connected with the optical switch connecting end I or the optical switch connecting end II through the optical switch. According to the fiber bragg grating sensing wavelength calibration device based on cavity absorption, an absorption spectrum obtained by a reflection cavity is calibrated, the relationship between the spectrum CCD picture element position and the absorption spectrum central wavelength is established, and then calibration of the central wavelength of each picture element is achieved; a calibration system is simplified, the measurement accuracy of a fiber bragg grating sensing system is greatly improved, and the measurement range of the fiber bragg grating sensing system is greatly enlarged.

Description

technical field [0001] The invention relates to a wavelength calibrating device in a fiber grating sensing system, in particular to a fiber grating sensing wavelength calibrating device based on cavity absorption. Background technique [0002] The fiber grating sensing system monitors the change of external temperature or stress by detecting the movement of Bragg wavelength. There are many ways to detect the Bragg wavelength. The volume grating-based demodulation method has the advantages of good dynamic characteristics and has attracted extensive attention. For volume grating-based demodulation methods, the volume grating acts as a dispersion device. After the parallel light hits the volume grating, different wavelengths will be transmitted from different directions, and will be incident on the linear array CCD after passing through the converging lens, and the same wavelength will fall on the same position of the CCD, and the wavelength and the position of the CCD are one...

AI Technical Summary

Problems solved by technology

However, due to external influences, the corresponding relationship between the position of the CCD and the wavelength may drift slightly, so it must be calibrated during use

However, in the current FBG sensing scheme based on volume grating, the calibration method has not attracted much attention,

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