Method and equipment for optical fibre optical grating sensing network demodulation

Abstract

The invention relates to an optical fiber Prague raster sensing network fast demodulating method and a device thereof. The invention uses a narrow linewidth continuous semiconductor laser as an optical source; acousto-optic modulators are asymmetrically arranged inside a Sagnac ring; a FBG sensing network is connected with the Sagnac ring through a three-port 3-dB optical fiber coupler; each FBG in series at the sensing network has the consistent Prague wavelength with the central wavelength of a laser optical source under a room temperature; the acousto-optic modulator is driven by the radio-frequency signal with changeable frequency. When the frequency of the radio-frequency signal is changed, the transmissivity of a Sagnac interferometer is changed. The drift rate of the Prague wavelength of each sensing FBG at the sensing network is obtained by fast Fourier transform and related operations, and the sensed physical quantity variation is obtained finally. The method is a novel FBG sensing network which is suitable for the field which requires the sensing network with multiple nodes, high precision, good electromagnetic interference resistance and real time monitoring.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and is suitable for the field requiring multi-node, high-precision, good anti-electromagnetic interference and real-time monitoring sensor networks. In particular, it relates to a new method of using the acousto-optic modulator to change the frequency of the light wave to cause the effect of the asymmetric structure of the interferometer and the fiber Bragg grating (FBG) hypotenuse detection technology to realize the FBG sensor network demodulation method, and the implementation of the method equipment. Background technique [0002] FBG has become an important device for optical fiber sensing due to its unique advantages of optical fiber internal sensitivity, wavelength coding, and easy networking. Based on the developed wavelength division multiplexing (WDM) and time division multiplexing (TDM) technologies, fiber grating arrays are widely used in optical fiber quasi-distributed s...

AI Technical Summary

Problems solved by technology

Both sets of multiplexing technologies require high-cost light sources and complex demodulation systems, which directly lead to the high cost of the FBG sensor network and limit many of its practical applications.

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