Research In All-purpose Demodulation System For FBG And F-P Sensors Based On ARM

Optic fiber sensor is used in many areas because of its wonderful capability, such as in the health monitoring of structures, electricity industry, medicine, chemicao engineering etc. Fiber Bragg Grating (FBG), one kind of the fiber optical sensors, is often needed owe to its wavelength-decoded characteristic and multiplexing ability. Fiber Fabry Perot (F-P) sensor is also utilized as the advantages of high measurement accuracy, low cost and insensitivity of temperature fluctuation. However, fiber F-P sensor and FBG sensor are usually both needed in one system. So, it is demanded to make a set of general demodulation system for FBG and F-P, with low cost, good reliability, and easy portability.The principle of FBG and FFP sensor, some methods of demodulation are introduced. Analyzing the advantages and disadvantages of the demodulating methods, one demodulating method that based on Fabry Perot tunable filter is presented. The theoretical feasibility of the demodulating method is verified with the optic fiber sensor method.Signal processing and embedded systems based on ARM are popular in the world. ARM has many merits such as high operation speed, low consumption and so on. So the system based on ARM has a lot of benefits.The festure of ARM are analyzed and the CPU of sumsung S3C2440 is choosed to acquisting and computing. Driving programs, controlling programs and demodulating programs are designed on Linux. A PC interface is designed with VC. The system is checked and the results are analysed.