A Torsion Sensor Based on Tilted Few-Mode Fiber Grating

Abstract

The invention discloses a torsion sensor based on a tilted few-mode fiber grating, including a broadband light source, a polarizer, a polarization controller, an optical fiber fixing clip, a tilted few-mode fiber grating, a fiber rotator, and a spectrometer, wherein the polarization controller The optical fiber rotator is connected to the spectrometer through a few-mode optical fiber through a tilted few-mode fiber grating; the optical signal sent by the broadband light source is transmitted to the polarizer through a single-mode optical fiber to obtain linearly polarized light, and the polarization control is used The optical fiber rotator changes the polarization state of the linearly polarized light, and rotates the fiber rotator to twist the tilted few-mode fiber grating, excites the high-order mode of the tilted few-mode fiber grating and transmits it to the spectrometer through the few-mode fiber, and the tilted few-mode fiber is obtained by the spectrometer The transmission spectrum of the grating. The invention can utilize the property that the polarization state of the high-order mode in the few-mode fiber changes with the twist of the fiber, and realizes the sensing of the twist of the fiber by tilting the transmission spectrum of the few-mode fiber grating, and has high sensitivity.

Description

technical field [0001] The invention relates to a torsion sensor based on an inclined few-mode fiber grating, belonging to the technical field of fiber grating sensors. Background technique [0002] Because of its ability to excite the cladding mode and enhance the interaction between the fiber and the outside world, tilted fiber gratings have always attracted people's attention, and have been widely used in the measurement of external environmental factors such as temperature, stress, and refractive index. In order to improve the sensitivity of tilted fiber gratings, commonly used methods include coating thin-film media on the outside of the fiber, and using long-period gratings and other structures. However, ordinary tilted fiber gratings are not very sensitive to fiber torsion. In order to realize the sensing and measurement of torsion, Dawei Yu et al. used the few-mode optical fiber with elliptical core as the sensing of torsion. However, how to better measure the twis...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a torsion sensor based on a tilted few-mode fiber grating. The fiber grating torsion sensor before the solution has low sensitivity, and the signal is prone to attenuation during work. As a result, it is impossible to accurately measure the twist angle of the fiber by using the change of the transmission spectrum

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