Data Sampling And Signal Processing Of A Distributed Polarization Coupling Analyzer

Distributed polarization coupling analyzer (DPCA) is a white-lightinterference system capable of detecting the location and the intensity of thepolarization coupling points in the polarization maintained fiber (PMF). Itcan be used to improve the precision of fiber-optic gyroscope (FOG) andreduce the system cost. In this paper, wavelet analysis method is adopted toprocess the signals sampled by the DPCA.Main Works: Implemented with FPGA (Field Programmable Gate Array), the DPCAdata-sampling cards were designed to realize the data sampling. Themodel of DPCA signal processing was successfully built. Wavelet analysis was adopted to realize the signal processing of DPCA:Signal envelope extracting and signal filtering were successfullyrealized with Morlet wavelet and Daubechies wavelet respectively;Signal similarity was assured, and simultaneously the gain of SNR washighly improved after filter. The signal processing software was designed using Matlab and VC++. The influences of the light intensity and the variation of denoisingthreshold on denoising effects were both analyzed. The range of thelight power was confirmed by experiments. Moreover, the theory ofDPCA signal processing with Wavelet analysis was validated.Innovations: The model of DPCA signal processing was established based on thePMF mode coupling theory. Wavelet analysis was introduced to DPCA signal processing. Moresmooth signal envelopes and better signal resolution were achieved.With Matlab and VC++ programming, the DPCA signal processing timewas reduced.