Research And Implemenlation Of Embedded Demodulation System For Fiber Bragg Grating Sensors

Fiber Bragg Grating with the characteristic of anti-electromagnetic interference, good stability, measurement site without electricity, wide measurement range, easy to form sensor networks, has been widely used in buildings, bridges, health care and Power sector and other fields. However, the fiber Bragg grating wavelength demodulation technology is still the main obstacle for its further development. It is one of the largest difficulties in the field of fiber grating sensor.Through in-depth investigating of current research status of fiber grating, and grasp the current trends, we have a clear direction of the study. Firstly, by using coupled mode theory, we analyze the sensitivity of the Bragg grating in temperature and strain. Secondly, in this paper we analyze several Bragg grating wavelength demodulation method, we have selected the fiber Fabry-Perot tunable wavelength demodulation filter program as the system solution and designed the optical system. In terms of signal processing systems, we design a FFP-TF controller, which can control FFP-TF accurately without distortion. We have designed high-precision photo detector that can be realized nw-level optical power detection. We design a complete wavelength demodulation synchronization algorithm which can achieve system synchronization. Finally, we use an embedded system as a Bragg grating wavelength demodulation system platform. STM32 system platform was determined by comparing the different platforms. We design a monitoring software for the Bragg grating wavelength demodulation to show results based on VC++. In order to meet portable needs, a handheld wavelength demodulation system is designed based on LCD touch-screen.The experiments result show that the FBG demodulation system with accuracy of 1℃in temperature measurement, the response time less than 1s, the system is stable, reliable, scalable, can meet the needs of the engineering measurements.