Fiber grating sensor based on composite grating linear array and sensing method

Abstract

The invention provides a fiber grating sensor based on a composite grating linear array. The fiber grating sensor comprises fibers and a composite grating linear array, and the composite grating linear array comprises a tilted grating and a Bragg reflection grating group which are connected to the fiber in series connection in order; wherein, one group of the tilted grating is provided, and the included angle between a cross section of the fiber and the tilted grating is 3-15 degrees; the Bragg reflection grating group comprises two or more groups of Bragg reflection gratings which are etchedalong the cross section of the fiber, and Bragg reflection wavelengths of each group of Bragg reflection gratings are different; wavelengths of cladding mode of the tilted grating and Bragg reflectiongrating reflection peak are synchronously influenced by temperature and strain, and the cladding mode of the tilted grating and the Bragg reflection gratings have same temperature and strain sensitivity coefficient. Grafting writing and fabricating technology is used for periodical rewriting of refractive index of a fiber core, in order to perform sensitivity characteristic of refractive index ofthe titled grafting, and realize a refractive index fiber sensing scheme without physical structure damage and mechanical property damage, and output an environmental refractive index sensitive reflection spectra without temperature and strain influences.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing, and in particular relates to an optical fiber grating sensor and a sensing method based on a composite grating line array. Background technique [0002] Refractive index-sensitive optical fiber sensing technology has gradually become the research focus and hotspot in the field of optical fiber sensing technology at home and abroad due to its advantages such as wide detection parameter range, simple structure, high precision, small size, good operability, convenient interpretation, and high reliability. . The refractive index is the ratio of the propagation speed of light in a vacuum to the propagation speed in a medium, and is an intrinsic physical property of a medium. The detection principle of the refractive index sensitive sensor is to use the optical parameter changes (such as resonance wavelength, light field intensity, and spectral changes) caused by the change of the environmental re...

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Problems solved by technology

The demodulation method adopted is transmission spectrum demodulation, and multiple optical structures cannot be connected in series to realize multi-point refractive index monitoring

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