Optical fiber hydrophone based on push-pull structure

Abstract

The invention provides an optical fiber hydrophone based on a push-pull structure. The device comprises a narrow linewidth laser, an optical fiber isolator, an optical fiber circulator, an optical attenuator, a photoelectric detector and a signal processing and display module which are connected in sequence, wherein one output port of the optical fiber circulator is connected with the optical fiber hydrophone sensing probe, and the other output port of the optical fiber circulator is connected with the optical attenuator; the optical fiber hydrophone sensing probe comprises an inner thin-wall elastic cylinder, an outer thin-wall elastic cylinder, an upper end cover, a lower end cover and a cover plate; when the inner thin-wall elastic cylinder wound with the inner optical fiber ring is nested in the outer thin-wall elastic cylinder wound with the outer optical fiber ring, an air cavity is formed between the two thin-wall elastic cylinders; one end of the inner fiber loop is connected with the second Faraday rotating mirror, and the other end is connected with the first input end of the coupler; one end of the outer fiber loop is connected with the first Faraday rotating mirror, and the other end is connected with the second input end of the coupler; and the output end of the coupler is connected with the optical fiber circulator.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing and underwater acoustic signal detection, in particular to a double-sensitivity, low-noise interference optical fiber hydrophone based on a push-pull structure. Background technique [0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art. [0003] Acoustic waves are the only form of energy capable of long-distance transmission in the ocean, and the transmission distance of low-frequency acoustic waves can even reach thousands of kilometers. At present, the main technical means for detecting and identifying underwater targets is still the detection of underwater acoustic signals. Compared with traditional piezoelectric hydrophones, optical fiber hydrophones have gradually replaced traditional piezoelectric hydrophones due to their advantages such as high sensitivity, immunity to electromagnetic in...

AI Technical Summary

Problems solved by technology

[0004] Chinese patent: CN111256807 B discloses a small-size interference fiber optic hydrophone based on a folded air cavity. The fiber optic hydrophone includes four thin-walled hollow tubes and fiber optic interferometers that can be nested and installed. Although the sensitivity is improved, The structure is compact, but the manufacturing process is complex, and the interferometer is not fixed, which will affect the stability of the detection results

[0005] Chinese patent: CN112649839 A discloses a push-pull fiber optic hydrophone, which uses metal parts and elastic bodies as sensitive elements to form a push-pull structure, but due to the large performance difference between the two sensitive elements, the sensitivity improvement is small, and the The structure is mainly used to solve the unreliable water leakage problem of the fiber optic hydrophone in the long-term working environment on the seabed

Images