Fiber bragg grating wavelength demodulation system with long-period fiber bragg grating Sagnac loop

Abstract

The invention relates to a fiber bragg grating wavelength demodulation system with a long-period fiber bragg grating Sagnac loop, belonging to the optical fiber sensor field. In the system, the light source of the demodulation system is a line cavity type fiber laser formed by using a fiber Bragg grating (4) and the Sagnac loop (8) with a long-period fiber bragg grating as the endoscopy; one end of the long-period fiber bragg grating (7) is connected with the third port (63) of a 2*2 coupler, the other end of the long-period fiber bragg grating is connected with the fourth port (64) of the 2*2 coupler, thus forming the Sagnac loop with the long-period fiber bragg grating; one end of the fiber Bragg grating is connected with the first port (61) of the 2*2 coupler through an Er-doped fiber (5), the other end is connected with the third port (63) of a wavelength division multiplexer; the second port (32) of the wavelength division multiplexer is connected with a pump light source (2), and the first port (31) of the wavelength division multiplexer is connected with a signal processing system (1). By using the demodulation system of the invention, the defects that signal-to-noise ratio and measurement precision are low and the system is subject to environmental disturbance.

Description

technical field [0001] The invention relates to an optical fiber grating wavelength demodulation system containing a long-period optical fiber grating Sagnac ring, belonging to the technical field of optical fiber sensors. Background technique [0002] Fiber Bragg grating sensors have the advantages of strong anti-interference ability, good reliability, corrosion resistance, small size, light weight and reliable wavelength encoding method, etc., and are more and more valued by people. This kind of sensor converts the change of the measured parameter into the change of the working wavelength of the grating. How to demodulate the small wavelength drift simply, quickly and accurately is a crucial issue in the fiber grating sensor system. [0003] At present, the practical wavelength demodulation technology of fiber grating mainly includes interference demodulation technology, tunable F-P filter demodulation technology and spectral imaging technology combining dispersive element...

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