Torsion and displacement measuring sensor based on optical fiber acousto-optic modulation

Abstract

The invention relates to an optical fiber acousto-optic torsion and displacement sensor and more particularly, to a torsion and displacement sensor arranged on an acousto-optic modulator based on a few-mode or multi-mode optical fiber. The optical fiber acousto-optic torsion and displacement sensor of the invention, more particularly, relates to a torsion and displacement sensor arranged on an acousto-optic modulator based on a few-mode or multi-mode optical fiber. The sensor of the invention is designed to overcome the axial angle torsion in construction structure security and internal damage detection as well as the shortcomings of the current technology of a micro displacement sensor and therefore, an optical fiber acousto-optic torsion and displacement sensor suitable for use in a micro space dangerous environment is provided. Through the transmission of detection light in different modes by the optical fiber acousto-optic modulator through one single few-mode optical fiber, the detection light is converted by the different angle torsions and the micro displacement amounts of a detected object into the torsion amount and the displacement amount of an image monitoring and capturing system; and an image identifying algorithm realizes the dynamic monitoring. According to the invention, in a dangerous environment, the sensor can simultaneously the axial torsion and the three-dimensional micro displacement of a detected object, and is not provided with the intersecting sensitivity between the temperature and the axial stress, therefore, capable of being created by a cost-effective image identifying system.

Description

technical field [0001] The invention relates to an optical fiber acousto-optic torsion and displacement sensor, in particular to a torsion and displacement sensor based on setting up an acousto-optic modulator on a few-mode or multi-mode optical fiber. Background technique [0002] With the continuous development of large-scale infrastructure (such as bridges, hydropower stations, roads and railways, etc.), intelligent buildings, mechanical devices and high-risk environment buildings (such as chemical warehouses, oil storage depots and nuclear power plants, etc.), the safety of building structures and internal damage detection demand has grown dramatically. The angular torsion of the central axis and the three-dimensional micro-displacement in space are important indicators for detecting structural damage and internal safety. Due to the limitation of the narrow space scale, the traditional large-area contact sensor cannot place the sensing head inside the building, resultin...

AI Technical Summary

Problems solved by technology

[0006] The traditional angular twist is not only sensitive to torsion and displacement, but also sensitive to the ambient temperature and the axial stress of the fiber. This cross-sensitivity leads to inaccurate sensing of torsion and displacement at the output end.

[0007] Traditional optical fiber sensors generally use spectrometry to measure changes in the wavelength and amplitude of the output light spectrum, while the spectral measurement receiver processing method is complex, slow and expensive, so it is difficult to achieve high-speed dynamic monitoring and is not suitable for reducing the entire sensor. cost

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