摘要：In order to detect the wavelength drift of FBG (fiber Bragg grating) sensors, the real- time demodulating system based on tunable F-P filter (TFPF) was built. The optical parts of the demodulation system include broadband optical source, TFPF unit, reference grating model, sensing grating array, and couplers. The electronic parts of the demodulation system consist of AD converting unit, DA converting unit, field programmable gate array (FPGA) unit and human-computer interaction unit. With the high-speed data processing capacity, FPGA was utilized to realize digital logic circuits of the demodulation system. It includes resetting unit, phase locked loop (PLL) unit, driving TFPF unit, detecting keys unit, LCD displaying unit, FIR filtering unit and data calculating unit. The demodulating system has such features as high reliability and speed, instantaneity, and programmability. It can satisfy the requirements of wavelength demodulation of FBG sensors in practical engineering.
