Multiplexing demodulation equipment based on long-cycle fiber grating reflective sensor

Abstract

The invention relates to multiplexing demodulation equipment based on long-cycle fiber grating reflective sensors.The multiple long-cycle fiber grating reflective sensors are provided with different optical path differences; a broadband light source is connected with the first port of a three-port circulator, the second port of the three-port circulator is connected with an optical fiber connected with the multiple long-cycle fiber grating reflective sensors in series, and the third port is connected with the input end of a first optical fiber coupler; an output end of the first optical fiber coupler is connected with the input end of a polarization controller, and the other output end of the first optical fiber coupler is connected with the input end of an electric adjustable delay line; the output end of the polarization controller and the output end of the electric adjustable delay line are connected with two input ends of a second optical fiber coupler; the output end of the second optical fiber coupler is connected with the input end of a photoelectric detector, and the output end of the photoelectric detector is connected with a data acquisition card.By means of the multiplexing demodulation equipment, system spatial resolution is high, the reusable number is large, and cost is low.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a multiplexing demodulation device based on long-period optical fiber grating reflective sensors. Background technique [0002] In the field of optical fiber sensing, long-period fiber gratings have become a very important sensing device due to their high sensitivity to changes in temperature, stress and strain, and environmental refractive index. Compared with Bragg gratings, long-period fiber gratings have higher sensitivity to temperature, stress, etc., and its cladding mode is sensitive to the refractive index of the external environment, which can be applied to high-precision measurement of the refractive index of liquids. Although it has excellent single-point sensing performance, the practical progress of long-period fiber gratings in the application field lags far behind Bragg gratings. Due to its narrow frequency-domain reflection bandwidth, generally less...

AI Technical Summary

Problems solved by technology

The multiplexing demodulation system based on the principle of low coherence is a multiplexing system with excellent performance and low cost, but the application research of this system is still far behind the time division multiplexing system, wavelength division multiplexing system, etc.

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