Optical fiber strain sensor

Abstract

The invention discloses an optical fiber strain sensor. The optical fiber strain sensor comprises a pipe shell, wherein end covers are respectively mounted at the two ends of the pipe shell, an optical fiber grating is arranged in the pipe shell, the optical fiber grating comprises a first optical fiber grating and a second optical fiber grating, which are connected into a whole, the two ends of the first optical fiber grating are respectively correspondingly fixed on the two end covers and pre-tensioned, the second optical fiber grating is fixed on one of the end covers, the free end of the first optical fiber grating and the free end of the second optical fiber grating extend out of the corresponding end covers, a strain desensitization beam is mounted in the pipe shell, the strain desensitization beam comprises an intermediate fixed part and two edge strain desensitization parts which are connected with the two sides of the intermediate fixed part and are in mirror symmetry, the intermediate fixed part is fixed on the inner wall of the pipe shell, the free ends of the two edge strain desensitization parts are fixedly connected with the first optical fiber grating, and the length of the optical fiber grating between the adhesion points of the two edge strain desensitization parts and the first optical fiber grating is a plurality of times of the transverse length of the intermediate fixed part. The optical fiber strain sensor disclosed by the invention has the advantages of large measurement range and high accuracy.

Description

Technical field [0001] The invention relates to a strain sensor, in particular to an optical fiber strain sensor. Background technique [0002] Traditional strain sensors are based on strain-electricity, and use electrical signals as the carrier for conversion and transmission. The electrical signals are transmitted by wires. Therefore, they are easily affected by electromagnetic fields and the environment during use. If the environment humidity is too high, it may cause short circuits. It is easy to cause fire in high temperature, flammable, and explosive environment. [0003] Studies have found that when the strain of the fiber grating changes, the effective refractive index and the grating period of the grating will change, which will cause the center wavelength of the fiber grating to also change. For example, for a fiber grating with a center wavelength of 1550nm, 1 micro strain ( That is, 1με) will cause a wavelength change of about 1pm. By measuring the change of the centra...

AI Technical Summary

Problems solved by technology

Because the wavelength drift of fiber gratings is usually affected by temperature, the measurement accuracy is low and the measurement error is large (generally around 5% to 10%)

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