Diaphragm type low-fineness F-P optical fiber sound pressure transducer based on FBG

Abstract

The invention discloses a diaphragm type low-fineness F-P optical fiber sound pressure based on an FBG transducer, which belongs to the technical field of optical fiber transducers and aims at solving the defects of a conventional F-P optical fiber sound pressure transducer. The transducer comprises a low-reflectivity FBG written in an optical fiber, a sleeve, a sensitive diaphragm arranged at the end surface of the sleeve and an optical fiber, wherein a pair of reflectors of an F-P cavity is formed by the FBG and the sensitive diaphragm, an interference cavity of the F-P transducer is formed by the optical fiber and an air cavity from the end surface of the optical fiber to the sensitive diaphragm, the length of the interference cavity has good processing repeatability, and the two reflectors of the interference cavity are high in depth of parallelism; the effective reflectivity of the diaphragm is approximately same as that of the FBG by controlling the distance between the outgoing end surface of the optical fiber and the sensitive diaphragm; and the transducer adopts a PGC demodulation technology, thus having strong anti-interference capability for slowly-changing factors such as temperature and laser wavelength drift.

Description

technical field [0001] The invention relates to an F-P pressure sensor, in particular to a FBG-based diaphragm type low-precision F-P optical fiber sound pressure sensor, 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 F-P sensor is coated with a layer of high reflection film on the end of the optical fiber as a high reflection mirror, and the sensitive diaphragm is used as another reflection mirror. The two reflection mirrors form an F-P cavity. When external factors act on When the diaphragm is sensitive, the vibration of the diaphragm will cause the cavity length to change, and the interferometric measurement of th...

AI Technical Summary

Problems solved by technology

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

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