A membrane-type high-precision Fabry-Perot fiber optic acceleration sensor based on fiber Bragg gratings

Abstract

An FBG-based diaphragm type high-precision F-P optical fiber acceleration sensor belongs to the technical field of optical fiber sensors. The present invention aims to solve the defects existing in the traditional F-P sensor. Write the FBG in the optical fiber, the sensitive diaphragm, the collimating lens facing the exit end of the optical fiber, the pigtailed sleeve, the optical fiber, and the sleeve; the sensitive diaphragm is set on one end of the sleeve, and the collimating lens and the sleeve are fixed inside the sleeve. With a pigtail sleeve, the pigtail with a pigtail sleeve passes through the other end of the sleeve to connect with the optical fiber, and a raised mass block is set in the middle of the sensitive diaphragm; FBG and the end face of the raised mass block on the sensitive diaphragm constitute A pair of mirrors in the F‑P cavity; the FBG to the fiber exit end face, the collimator lens, and the air cavity from the collimator lens to the raised mass together form the cavity length of the F‑P. The sensitive diaphragm makes the optical fiber sensor have very high sensitivity. The output signal of the sensor is demodulated by phase demodulation method, which has strong anti-interference ability to 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 acceleration 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 extri...

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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