Research On The Demodulation Method Of Optical Fiber Grating Sensing Signal

Optical fiber sensing technology is a new sensing technology that has many advantages. It has been widely used in industry, agriculture, military, medical and other fields. This article which studied the wavelength demodulation issue of fiber Bragg grating sensing and measurement subject has practical significance and academic value.This thesis summarized the principle, the research and application condition, development and technical characteristics of fiber Bragg grating (FBG) sensing technology that based on a lot of investigation and analysis. The measurement principle of FBG sensing system based on tunable Fabry-Perot filter has been illustrated. The characteristics of FBG sensor demodulation signal and noise model which generated in optical system have been analyzed. Using LabVIEW and MATLAB simulation software produced a FBG sensor demodulation signal which included noise. Propose a signal processing which is realized by software and the main study of this processing is filter and peak-detection. Each step of the process has been analyzed in detail and simulated by LabVIEW software. There are seven traditional filtering algorithms including limiting filter, moving average filtering, median filtering, five-spot triple smoothing, IIR filter, FIR filter, zero phase filter have been simulation analyzed. There are nine peak searching algorithms, including centroid, Gaussian fitting, polynomial fitting, spline fitting, RBF fitting, deconvolution methods, spectral correlation, semi-peak detection method, the slope intersection method have been simulation analyzed and obtained a lot of data. The advantages and disadvantages of filter algorithms and peak-detection algorithms were analyzed and compared.With the current relevant literature, using stationary wavelet transform (SWT) to process FBG signal was proposed. By comparing the performance of SWT and others, the advantages of SWT were found.The control software of FBG sensing system using a tunable Fabry-Perot filter was developed. By combining the software and the hardware experiment is did. The experiments show that the control software can be normal collected spectral data and stable operation of each control features. Meanwhile, the processing that was be proposed by the paper was proved to be effective.