The Research On Sensing Signal Demodulation Based On ARM Technology For Fiber Bragg Grating

Due to all its merit, such as excellent electric insulation, resistance of the interference of electromagnetic, high sensitivity, small volume, light weight, Fiber Bragg grating (FBG) sensor is widely used in structure monitoring of the large compound material and concrete, the performance monitoring of the intelligent materials, electric power, medicine, chemical engineering. Now, it's becomes one of the most important part of the sensing research, while among this the sensing signal demodulation technique is the more important and difficult part, and get more attention. Although a large number of research and investigations on the demodulation methods of FBG have been done in domestic research institutes,most of the researches are still in lab-experimental stage, and have not yet met the requirements of the practical industrial mass productions.Tthe recent development in the area of optical fiber grating sensors are reviewed in this paper. The method of fiber grating fabrication is introdeced briefly. The characteristics and applications of FBG sensor are introduced systematically. In the article, both advantages and disadvantages of all kinds of FBG demodulation scheme are analyzed. Tthe coupled-mode theory of the light transmitting in fiber is expatiated and based on which the Bragg formula and reflectivity/transmission formula is deduced. We also analyzed the sensing principle of FBG strain sensor, press sensor and temperature sensor.Signal processing and embedded systems based on ARM are popular research fields now. ARM has many merits such as high operation speed,low power consumption,abundant interfaces,convenience in embedding real-time operating systems, etc. The demodulation system asopted in this paper demodulates signal with ARM, and it has many benefits:Above all, high processing capability improves the precision and speed of signal demodulation secondly, abundant interfaces make the demodulation system have a good man-machine interface. Last, the system's cost decreases because ARM integrates many components. The tunable F-P cavity method applied to the demodulation system based on ARM system is proposed. In order to improve the speed and accuracy of demodulation, the ARM system based on S3C44B0X is used in the system. In this paper, the Flash ROM operation and the Boot Loader in ARM system are explained. The demodulation system also has serial ports and JTAG ports, using serial port to transfer the demodulation data. So the system can not only demodulate FBG signals, but also provide a extended interface, which would be convenient for future use.