Hardware Design Of The High-speed Fiber Grating Demodulation Instrument Based On FPGA

Fiber Bragg Grating (FBG) is a new type of sensor. It has a lot of features that conventional sensors can not match with. In recent years, the sensing detection technology based on FBG is booming, due to its electrical insulation, resistance to electromagnetic interference, resistance to acid corrosion, small size, light weight, high sensitivity and so on. So it is widely used in the coal industry, the oil industry, the field of chemical industry, aerospace, the health monitoring of the building, the dynamic monitoring of the complex mechanical systems and so on. A variety of the demodulation solutions about FBG emerged, also with the continuous expansion of the applications, the accuracy and the frequency of the demodulation system requires to be much better, which greatly promote the research on FBG sensor demodulation technique at home and abroad.There are some products based on different solutions related on the FBG sensor demodulation at home and abroad now. These products always perform not so well because of the low demodulation frequency, or the complex structure, or the expensive price, which greatly hindered the popularity of the FBG sensing technology. The hardware system based on FPGA can take full advantage of the high-speed, high-customizable and simple structure, and then achieve the high-speed FBG demodulation solution with lower cost.The basic principles of the FBG sensor and the demodulation method will be analyzed first in this paper, and then we will research the design and implementation of FBG sensor demodulation system based on the fiber F-P filter demodulation method. So the salutation based on embedded acquisition platform and terminal platform with PC is provided according to the industrial requirement, interfaces, and scalability requirements and so on. Then we will design the embedded acquisition platform based on FPGA. The platform includes four parts:the FPGA system module, the optical devices driver module, the signal conditioning module and the power module. The test and debug method will be given out after the hardware design, and then a whole test will be executed combined with the PC software system. The tests include the system accuracy test, the temperature test, the intensity decay test and the vibration signal test. After that a report will be given out according to the test data, the theory of the FBG and the reference of foreign products. Thus, the feasibility of the FBG demodulation system based on FPGA will be demonstrated, because that the demodulation accuracy, temperature characteristics, dynamic range and demodulation frequency are all fit enough. Finally, a brief summary about the hardware designs of the system will be listed to show the topic of the research and the inadequate of the design, and then a further work for the next step will come after that.