Research On Matching Grating Driver And Wavelength Reconstruction

As a result of the characteristic of anti-electromagnetic interference,highsensitivity,anti-corrosion and other advantages, Fiber Bragg Grating (FBG) is being oneof the current hottest researches in the optical fiber grating sensor technique field afterbeing invented. And FBG has a unique advantage with its characteristic of wavelengthencoding and linear strain and temperature response. However, how to improve thedemodulation accuracy of FBG sensor is being a research hotspot and difficulty fornow.This paper reviews the development of FBG since its inception, and summarizesand analyzes the advantages and disadvantages of a variety of FBG sensingdemodulation methods. Considering the conditions of laboratory and the practicalfeasibility of the method, grating-matching demodulation method is adopted in thispaper. After determining the demodulation scheme, physical mechanism of theinterferometric noise is described. In order to solve problem of the noise, the digitalsignal processing method, which is named wavelet analysis, is combined with FBGsensing. This is called wavelength reconstruction, which can improve the demodulationaccuracy effectively.The major research work is as follows: the classification of the fiber grating andthe developing situation of FBG sensors are analyzed in this paper; and secondly, themethod of FBG sensing demodulation based on matching grating and the selection ofexperimental apparatus is introduced; to resolve the problem of the noise, the model of theinterference noise is established and the method of Wavelet denoising is presented byusing mixed programming of VC++and MATLAB; and finally,we are debugging thewhole system including the optical parts, the hardware and software. The system isusing A/D converter and the serial communication interface realizing data transfer fromthe system to the host PC. We can obtain the reliable results after the experiment, and thenwe process the data by using the method of wavelet analysis and complete error analysis. Theresult of the experiment proved that the wavelength detection accuracy can be enhanced anorder of magnitude after using the method of wavelet analysis.