Optical fiber vector vibration sensor

Abstract

The invention discloses an optical fiber vector vibration sensor. The optical fiber vector vibration sensor comprises a broadband light source, a polarization control unit, a sensing probe and an orthogonal polarization demodulation unit, wherein the polarization control unit comprises a polarizer and a polarization controller; the sensing probe comprises a multi-mode tilted optical fiber grating, a cladding layer-fiber core energy recoupling structure and a polymer elastic tube; the multi-mode tilted optical fiber grating and the cladding layer-fiber core energy recoupling structure are encapsulated in the polymer elastic tube and used for sensing environment vibration information; the multi-mode tilted optical fiber grating is made of a multi-mode optical fiber; the cladding layer-fiber core energy recoupling structure is welded in a manner of axially aligning multi-mode and single-mode optical cores; the orthogonal polarization demodulation unit comprises a polarization beam splitter, a filter and a photoelectric detector; and the polarization control unit, the sensing probe and the orthogonal polarization demodulation unit are connected by virtue of an optical fiber circulator or a coupler. The optical fiber vector vibration sensor disclosed by the invention can recognize two-dimensional vibration direction based on single optical fiber grating, and has the advantages of high sensitivity, compact structure, low cost and easiness for networking.

Description

technical field [0001] The invention relates to the field of vibration sensor design, in particular to an orthogonal polarization optical fiber vector vibration sensor capable of identifying vibration directions. Background technique [0002] Vibration sensors are widely used in building structural health detection, earthquake disaster prevention, oil and gas exploration, and national defense security monitoring. For example, by detecting the structural deformation of large-scale civil engineering (bridges, tunnels, dams, etc.) Timely diagnosis of its health status; by recording the source of the earthquake, studying the internal structure of the earth and the characteristics of seismic wave propagation, to realize the prediction of impending earthquake; by detecting the elastic wave caused by the reflection or refraction of artificial vibration through the interface of the rock layer, it is possible to understand the underground geological structure to search for oil and gas...

AI Technical Summary

Problems solved by technology

This type of electronic vibration sensor can be divided into moving coil type, eddy current type, piezoelectric type, piezoresistive type, etc. in terms of working principle, but the following problems generally exist: it is susceptible to electromagnetic interference, especially electronic devices are prone to sparks, and in There are safety hazards in the application in the field of oil and gas exploration

However, the miniaturized and networkable sensing technology based on a single optical fiber sensing unit to realize multi-dimensional vibration direction identification has not been reported yet.

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