Research On Fiber Bragg Grating Demodulation System

FBG sensor is one of the current heat research fields in the optical fiber grating sensor technique fields. It is widely applied in many fields such as the structure monitoring of the large compound material and the concrete, the performance monitoring of the intelligent materials, electric power industry, medicine, chemical engineering etc. The demodulation technique of the FBG is currently a critical and difficult problem in nowadays FBG censoring technique fields. Although a large number of researchers in domestic research units have been doing a lot of research and investigations on the demodulation methods of FBG, most of the researches are still in the phase of lab experiments and have not yet met the requirements of the practical industrial mass productions.The fiber grating sensor theory and technology is systematically researched in this paper. The main content includes: the principle of fiber grating sensor; the analysis of several technologies of demodulation and the F-P filter demodulation is introduced in detail; the design of demodulation system based on DSP.Firstly, the recent developments in the area of optical fiber grating sensors are reviewed. The method of fiber grating fabrication is introduced briefly.The demodulation method of fiber grating is the key method of fiber grating sensor. The main demodulation method includes: grating matching method, tunable Fabry-Perot cavity method, non-balance Mach-Zehnder interferometer method and tunable narrow-band light source method. The tunable Fabry-Perot cavity method is discussed in detail, and a demodulation system based on DSP is put forward.DSP technology is a powerful tool in signal processing fields. In order to implement the speed and accuracy of demodulation, TMS320VC5402 is used in the system. The design method of DSP and the F-P driving voltage is introduced in the thesis. In order to match the DSP, the system logic circuit is implement by Complex Programmable Logic Circiut.Bootloader is required in DSP system, a new way to bootloader and the flash operation method are introduced in this paper.