Design of multichannel distributed fiber grating sensor demodulation system

Fiber grating sensors have been widely used in many fields, The demodulations of resonance wavelength shift and reflectivity variation are the key technology in the practical application of fiber grating sensors. Demodulation technology based on ARM and FPGA for multi-channel distributed fiber grating sensing network was researched. The demodulation system include two modules: a modulation module and a demodulation module. The modulation module consists of a broadband light source, an coupler, an optical switch and an optical fiber grating sensor array; The demodulation module consists of a tunable filter, a photoelectric detector, a power amplifier, FPGA and ARM control system. Half peak discriminance for the resonant peak detection was used when data acquisition was taken. The precision of the sensing measurement of the center wavelength shift was able to achieve l pm. The system has the characteristics of multichannel, distributional, multi-point, high precision, high speed, small volume, low cost and easy to expand.