Method for measuring strain by aid of fiber F-P (Fabry-Perot) sensors

Abstract

The invention provides a method for measuring strain by the aid of fiber F-P (Fabry-Perot) sensors. The method includes manufacturing the fiber F-P sensors, fixing fiber fixtures onto high-precision three-dimensional movement platforms and fixing HI-1060 fibers without coatings onto the fiber fixtures; sequentially transmitting femtosecond laser through half-wave plates, polarizers, attenuation slices and windows, reflecting the femtosecond laser via high-reflectivity mirrors, then focusing the femtosecond laser on the HI-1060 fibers and carrying out scribing and writing on the HI-1060 fibers;arranging charge coupled devices right above the high-reflectivity mirrors and observing focusing locations of the laser and morphology of the HI-1060 fibers on the fixtures; constructing strain testsystems comprising broadband light sources, circulators, the fiber F-P sensors, movable stretching platforms and spectrum analyzers; fixing the fiber F-P sensors onto the movable stretching platformsand allowing the fiber F-P sensors to generate the strain; observing and recording reflection spectra of the fiber F-P sensors by the aid of the spectrum analyzers in real time. The HI-1060 fibers with the observed morphology are processed by the laser. The method has the advantage that the fiber F-P sensors manufactured by the aid of the method are high in strain measuring sensitivity.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensors, in particular to a method for measuring strain by an optical fiber F-P sensor. Background technique [0002] In recent years, fiber optic sensors have been widely used in the fields of physical, chemical, and biological sensing due to their light weight, small size, corrosion resistance, anti-electromagnetic interference, and high sensitivity. The fiber optic F-P interference sensor is a phase modulation sensor, so it has the advantages of simple structure and high sensitivity. Optical fiber F-P interference sensors are divided into intrinsic type and extrinsic type F-P interference sensors. In the extrinsic fiber optic F-P interference sensor, because the medium in the cavity is air, the light in the F-P cavity and the optical fiber produce a large coupling loss. At present, the manufacturing methods of the intrinsic type optical fiber F-P interference sensor include methods such...

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Problems solved by technology

[0005] However, the above-mentioned intrinsic fiber optic F-P sensors are made by direct exposure of the femtosecond laser on the fiber core, and the contrast of interference fringes in the reflection spectrum is less than 10dB, and it is difficult to achieve high sensitivity in strain measurement.

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