Push-pull type fiber laser vector hydrophone

Abstract

The invention discloses a push-pull type fiber laser vector hydrophone, and relates to the technical field of optical fiber sensors. The push-pull type fiber laser vector hydrophone comprises two line-type cavity optical fiber lasers, two hollow-out drum-shaped optical fiber sensor element sensitization structures, a mass block, a rigid shell outer shell and two end caps, wherein resonant cavities of the two line-type cavity optical fiber lasers are connected in series, are respectively packaged in the two hollow-out drum-shaped optical fiber sensor element sensitization structures and are used for obtaining high sensitivity and a smooth acceleration frequency response, and the two sensitization structures share the mass block. When subjected to mass point acceleration action, due to the inertia effect, the mass block compresses one laser resonant cavity while the other laser resonant cavity extends, so that a push-pull type structure is formed. According to the push-pull type fiber laser vector hydrophone, a one-dimensional fiber laser vector hydrophone which is high in sensitivity, smooth in frequency response, and quite low in quadrature-axis crosstalk and background noise is achieved. By means of further combination and packaging, a multi- dimensional fiber laser vector hydrophone is realized.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensors, in particular to an optical fiber laser vector hydrophone. Background technique [0002] Optical fiber vector hydrophone is one of the important research frontiers of underwater sonar system, and has broad application prospects in underwater oil and gas exploration, seismic wave detection and other fields. Compared with the scalar hydrophone array with the same number of array elements, the output of the fiber optic vector hydrophone array itself already contains the direction information of the space target, which can improve the signal-to-noise ratio, improve the positioning accuracy of the target, and increase the aperture of the base array. It has outstanding advantages in reducing the size and weight of the array. However, since the detection element of the optical fiber vector hydrophone includes three vibration velocity sensing parts, the outer diameter of the detection elem...

AI Technical Summary

Problems solved by technology

[0005] Although the fiber laser vector hydrophone has potential advantages in miniaturization, low noise and other indicators, it is especially suitable for the development of ultra-fine vector hydrophone arrays, but because its sensing element is a linear laser resonator with a length of only a few centimeters The packaging process is limited, and conventional methods such as fiber winding and elastic coating will lead to increased noise or complete failure of the linear fiber laser resonator

In the research field of coupler-based interferometric optical fiber vector hydrophones, the push-pull packaging structure has been proved to be an effective means to increase sensitivity, reduce axial crosstalk and reduce noise, but because the optical fiber to be packaged in the optical fiber laser sensor is too short, and The push-pull of the laser resonator will cause the output of the laser resonator to be disordered, making it difficult to apply the push-pull structure to the design of fiber laser vector sensing

Therefore, the current main design idea of ​​the fiber laser vector hydrophone is the structure of the combination of the cantilever beam and the mass block, which can only realize the preliminary sensitivity enhancement function, and the crosstalk of the orthogonal axis is much larger than that of the interferometric fiber optic vector hydrophone based on the coupler. The hearing instrument will not only lead to the increase of noise, but also affect the positioning accuracy of the target, which cannot fully reflect the advantages of the fiber laser vector hydrophone

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