Research And Design Of Demodulation System Of FBG Sensors Based On DSP

With the development of large-scale building and infrastructures in China, more and more attention is paid to the structure health diagnosis. The traditional monitoring method cannot satisfy the requirement of construction industry. As fiber optical sensors have a great deal of advantages over traditional ones, they become the important research topic in the area of sensor and instrument. In particular, the optical fiber Bragg grating (FBG) sensors are widely used in engineering in virtue of their prominent characteristics.This paper systematically analyzed the detecting principle of FBG sensor and discussed the relative technical problems firstly and then put forward a scheme of wavelength demodulation based on FFP tunable filter. A set of wavelength reference is involved in the system as calibration to correct non-ideal performance of the F-P filter. A digital signal process system based on high speed digital signal processor (DSP) converters and analyses the analog signal from the conditioning circuit. Then the data was filtered by Butterworth low-pass filter and sent to PC104 via serial communication interface or USB. The realization of the hardware and the software of the digital signal process system is presented and the results of debugs is given in this thesis. Furthermore, a high precision demodulation scheme by D/A converter is also proposed.