Cascaded long-period fiber bragg grating multiplexing and demodulating device based on low-coherence interference principle

Abstract

The invention provides a cascaded long-period fiber bragg grating multiplexing and demodulating device based on a low-coherence interference principle. The device is composed of a broadband light source, a first coupler, a cascading the long-period fiber bragg grating, a second coupler, a Fizeau interferometer, a linear array InGaAs and a data storage and processing device. The broadband light source is connected with a port optical signal of the first optical fiber coupler, the first optical fiber coupler is connected with at least two cascaded long-period fiber bragg grating sensors, and thecascaded long-period fiber grating bragg sensors are connected with the second optical fiber coupler through an optical signal; the other interface of the second optical fiber coupler is optically connected with the input end of the Fizeau interferometer, an output optical signal of the Fizeau interferometer reaches the linear array InGaAs, and the linear array InGaAS is connected with the data storage and processing device. The cascaded long-period fiber bragg grating multiplexing and demodulating device based on the low-coherence interference principle has the advantages of being stable, and being high in spatial resolution, large in multiplexing number and low in cost.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a cascaded long-period fiber grating multiplex demodulation device based on the principle of low coherence interference. Background technique [0002] Cascaded long period fiber grating and its sensing principle [0003] Cascaded long-period fiber gratings are composed of two long-period fiber gratings with identical parameters written on the same optical fiber. As a special structure of long-period fiber gratings, cascaded long-period fiber gratings are essentially long-period fiber gratings. Sensing and measurement based on cascaded long-period fiber gratings obtain sensing information by changing the grating wavelength or the transmission depth at the resonant wavelength position caused by the external environment. The sensing mechanism of cascaded long-period fiber gratings includes temperature-induced deformation and thermo-optic effect, strain-induced deforma...

AI Technical Summary

Problems solved by technology

Due to the absence of reflection characteristics, the time-division multiplexing scheme using the measurement of pulsed light reflection delay is not suitable for long-period fiber grating arrays; and the transmission spectrum of long-period fiber gratings has multiple broad-spectrum loss band characteristics, resulting in wavelength division multiplexing. The plan cannot be realized

These factors make it difficult to multiplex modulation of cascaded long-period fiber grating sensing signals

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