A small-size interferometric high-frequency fiber optic hydrophone based on a folded air cavity

Abstract

The invention relates to the field of optical fiber sensing. The invention concretely relates to a small-size interference type high-frequency optical fiber hydrophone based on a folding air cavity. The optical fiber hydrophone comprises four thin-wall hollow cylinders which can be installed in a nested mode, the cylinders comprises a first thin-wall hollow cylinder provided with a first optical fiber winding area and a first supporting structure, a second thin-wall hollow cylinder with a second optical fiber winding area and a second supporting structure, a third thin-wall hollow cylinder with a third optical fiber winding area and a third supporting structure, and a fourth thin-wall hollow cylinder with a fourth optical fiber winding area and a fourth supporting structure. The hydrophonealso comprises an optical fiber interferometer. The optical fiber hydrophone has the advantages that on the premise that the winding area of the optical fiber is not reduced and the lengths of two arms of the optical fiber interferometer are reduced, the transverse size of the optical fiber hydrophone is greatly reduced, and the high-frequency application performance of the optical fiber hydrophone can be improved; and secondly, through the structural design of the multi-layer nested and a foldable air cavity, smaller radius and transverse size are realized, the resonant frequency of the mechanical structure can be improved, and the frequency response characteristic of the hydrophone is further optimized.

Description

technical field [0001] The invention relates to the field of optical fiber sensing, in particular to a small-size interference type high-frequency optical fiber hydrophone based on a folded air cavity, which is especially suitable for the detection of high-frequency underwater acoustic signals. Background technique [0002] Optical fiber hydrophone is a new type of hydrophone based on optical fiber sensing and optoelectronic technology. It is used to detect sound propagation, noise, reverberation, submarine acoustic characteristics, target acoustic characteristics, etc. in the marine acoustic environment. [0003] At present, the technical solutions of fiber optic hydrophones mainly include fiber grating type, fiber laser type and double-arm interference type. Among them, the double-arm interference type fiber optic hydrophone solution is the most mature and widely used. The basic principle is: the laser light emitted by the high-stability narrow-linewidth laser is divided ...

AI Technical Summary

Problems solved by technology

Secondly, in order to ensure that the sensitivity meets the practical requirements, the air cavity as a sensitization structure often needs to be designed as a slender shape to increase the area of ​​the fiber winding area. The resonance frequency of the entire structure is low, resulting in poor high-frequency performance of the hydrophone probe Conducive to the expansion of the response frequency band of optical fiber hydrophone

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