A quasi-distributed composite structure strain and temperature detection system

Abstract

The invention relates to a quasi-distributed composite structure strain and temperature detection system. Light output by a broadband light source passes through an optical fiber isolator and enters the input end of a 2*2 optical fiber coupler; the light output by the 2*2 optical fiber coupler enters the input end of a 1*m optical switch; the light output by the 1*m optical switch enters an m*n network type optical fiber grating sensing head; the light reflected by the m*n network type optical fiber grating sensing head sequentially passes through the 1*m optical switch and the 2*2 optical fiber coupler and further enters the input end of an optical fiber adjustable F-P (Fabry-Perot) filter; and the light output by the optical fiber adjustable F-P filter sequentially passes through a photoelectric conversion module, a signal amplifier, a data acquisition card and a computer, and the computer is used for processing and displaying data. The system utilizes the optical fiber adjustable F-P filter to realize wavelength demodulation of signal light reflected by all sensing optical fiber gratings, and has the advantages of anti-electromagnetic interference effect, all-optical fiber type measurement, a large number of multiplexing measuring points, remote monitoring, non-destructive measurement and the like.

Description

Technical field [0001] The invention relates to the technical field of optical fiber grating sensing, in particular to a quasi-distributed composite material structure strain and temperature detection system with multi-parameter measurement function and multi-point measurement function. Background technique [0002] Fiber grating is an optical element that establishes a certain spatial refractive index periodic distribution in the optical fiber, so that the propagation characteristics of light can be changed. Fiber grating is an optical element that establishes a certain spatial refractive index periodic distribution in the optical fiber, so that the propagation characteristics of light can be changed. When broadband light is incident on the fiber Bragg grating, the center wavelength of the reflected light (Brague wavelength) λ B , Given by Bragg's equation: λ B = 2nΛ [0003] Among them, n is the effective refractive index of the core, and Λ is the grating period. Since the meas...

AI Technical Summary

Problems solved by technology

In the prior art, if a fiber grating is used to measure multiple points, a spectrometer is often used to measure the wavelength signal, so that the cost of wavelength signal demodulation is relatively high; and the number of measurement points is limited by the bandwidth of the light source; and when the light source When the output power is constant, the larger the number of measurement points, the lower the signal-to-noise ratio, resulting in larger measurement errors

Therefore, the current fiber grating point multi-parameter system is usually low in cost performance, difficult to realize remote monitoring and poor in repeatability. At the same time, a large amount of useless data needs to be screened during measurement, and the signal-to-noise ratio of the measurement is not high, which affects the accuracy of the measurement.

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