A diaphragm-type high-precision Fabry-Perot fiber optic acoustic pressure sensor based on fiber Bragg gratings

Abstract

The invention provides an FBG-based diaphragm type high-definition F-P optical fiber sound pressure sensor, which belongs to the technical field of optical fiber sensors. Defects of a conventional F-P optical fiber sound pressure sensor are solved. The sensor comprises FBG written within an optical fiber, the optical fiber, a collimator lens which faces the end face of the optical fiber, a pigtailed sleeve, a casing which fixes the collimator lens and the pigtailed sleeve, and a sensitive diaphragm which is arranged on the end face of the casing. FBG and the sensitive diaphragm form a pair of reflector of an F-P cavity. From FBG to an outgoing end face and the collimator lens and from the collimator lens to an air cavity of the sensitive diaphragm form the F-P cavity length. Through the sensitive diaphragm, the optical fiber sensor has high sensitivity. An output signal of the sensor is demodulated through a phase demodulation method. The FBG-based diaphragm type high-definition F-P optical fiber acceleration sensor has a strong anti-jamming capability for temperature changes and laser wavelength drift.

Description

technical field [0001] The invention relates to a Fabry-Perot pressure sensor, in particular to a diaphragm-type high-precision Fabry-Perot optical fiber sound pressure sensor based on an optical fiber Bragg grating, which belongs to the technical field of optical fiber sensors. Background technique [0002] Optical fiber sensor technology is an emerging technology slowly formed with the development of optical fiber and optical fiber communication. It uses light as the carrier and optical fiber as the transmission medium to realize the sensing of the measured parameters. [0003] The traditional diaphragm-type extrinsic Fabry-Perot sensor is coated with a layer of high-reflection film on the end of the fiber as a high-reflection mirror, and the sensitive diaphragm is used as another reflector. The two reflectors form a Fabry-Perot sensor. -Perot cavity, which can realize the interferometric measurement of external signals. The cavity length of the traditional diaphragm ext...

AI Technical Summary

Problems solved by technology

The cavity length of the traditional diaphragm extrinsic Fabry-Perot sensor is short, and the small processing error of the interference cavity has a great influence on the demodulation result, so the processing repeatability of the interference cavity length is relatively difficult; when the environment When the temperature changes, it will cause a slow change in the length of the interference cavity, which will deteriorate the stability and accuracy of the demodulation results; interference factors such as wavelength drift will also affect the performance of the traditional diaphragm extrinsic Fabry-Perot sensor. Demodulation accuracy and stability; the traditional diaphragm extrinsic Fabry-Perot sensor requires two mirrors to be parallel during assembly, so assembly is difficult

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