Novel optical fiber torsion sensor insensitive to temperature, stress and light source intensity

Abstract

The invention discloses a novel optical fiber torsion sensor insensitive to temperature, tension and light source intensity and a preparation method thereof. The sensor is composed of three parts along the length direction, wherein the first part is composed of a plurality of femtosecond laser etching lines which are equally spaced and equal in length and are perpendicular to the axial direction of the optical fiber, and a group of reflection structures are formed. The second part is a conical area part, and the third part is completely the same as the first part. The first part and the thirdpart form an FP interference cavity, wherein the cavity length of the FP interference cavity is the distance between the two groups of reflection structures, and when the optical fiber is twisted, thecavity length of the interference structure formed by the two groups of reflection structures is not changed, but the polarization direction is changed, so that the interference condition of the interference structure is damaged, and the extinction ratio of a reflection spectrum is reduced. The torsion angle is calculated by measuring the variation of the extinction ratio of the reflectance spectrum. The design of the sensor can eliminate the interference of temperature, stress and light source intensity on the measurement result.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing and measurement, and more specifically relates to the invention and preparation of a novel optical fiber torsion angle sensor. Background technique [0002] The fiber optic torsion sensor has the advantages of high sensitivity, fast response, and no interference from electromagnetic fields. In recent years, it has been effectively applied in manufacturing industry, energy industry, medical treatment and other fields. Common optical fiber torsion sensors based on the principles of Bragg gratings, long-period gratings, and intermode interference have the advantages of small size, light weight, simple use, and good portability, and are currently widely used. However, since the refractive index of the quartz material in the optical fiber sensor is affected by the ambient temperature and stress, there are generally disadvantages such as low torsional sensitivity, inaccuracy, and susceptibility to ...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the defects or improvement needs of the prior art, the present invention provides the design and preparation method of a novel fiber optic torsion sensor that is insensitive to temperature, stress, and light source intensity. The measurement eliminates the left and right drift of the spectrum caused by temperature and stress, and eliminates the influence of the up and down drift of the spectrum caused by the change of light source intensity through the calculation of the extinction ratio.

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