Sagnac optical-fiber deformation sensor of low-coherent twisted torqued

Abstract

A Sagnac-like optical fiber sending device of low coherent twisted type is prepared as connecting optical source and photoelectric detector at a side of a coupler and connecting another side of said coupler to a closed loop formed by series-connecting various single-mode optical sending arms with 2x2 couplers. The closed loop is featured as out-setting single-mode optical fiber of high reflection surface and single-mode out-set optical fiber, using self-focusing lens and scan-reflector to form demodulation end of optical fiber and returning partial light back to light detector through said single-mode optical fiber.

Description

(1) Technical field [0001] The invention relates to an optical fiber deformation sensing device, which belongs to the technical field of optical fiber sensing, in particular to a sensing device for distributed measurement of deformation based on an optical low-coherence interference measurement technology. (2) Background technology [0002] Compared with traditional sensors, optical fiber sensors have the advantages of strong anti-electromagnetic interference ability, high temperature resistance, high pressure resistance, strong chemical corrosion resistance, light weight, high sensitivity, low loss and easy realization of distributed sensing. Since the mid-1970s, Research has grown into an emerging industry with an annual turnover of more than US$1 billion and is expected to have a market of more than US$5 billion in 2010. According to the statistics of the 15th annual International Optical Fiber Sensing Conference (OFS) sponsored by the Society of Optical Engineers (OSA), ...

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Problems solved by technology

The quasi-distributed fiber optic deformation sensor based on FBG can only measure the deformation at limited points, and cannot realize distributed measurement in the true sense. For example, the publication number CN 1680838A, the name is "Multimode Fiber Bragg Grating Sensor System", etc.; High-power coherent light source, distributed optical fiber sensor based on Raman scattering and Brillouin scattering, although the sensing distance is long, but the cost is expensive, such as the publication number CN 1400453A, the name is "distributed optical fiber temperature sensing system"; The low-coherence interference distributed optical fiber strain sensor, because its signal detection uses the principle of optical low-coherence interference, has the advantages of being able to realize the quasi-distributed absolute measurement of deformation and low cost, and has become a cost-effective one among these distributed sensors. kind

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