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布里渊光时域反射计结构的布里渊散射分布式光纤传感器检测的是自发散射光,信号非常微弱,而且频带在几十兆赫兹以上,难以应用普通相干解调方法。针对传感散射光信号特点,提出基于经典(Morlet)小波变换的光相干检测方法。首先采用微波电光调制产生频移参考光和自发布里渊散射光进行相干检测,再应用经典小波变换进行散射光信号的幅度解调,得到信噪比改善的布里渊散射传感光信号。给出了数值模拟和实验数据处理结果,表明经典小波变换能较好地处理布里渊光时域反射计检测信号。并和基于希尔伯特(Hilbert)变换的传感信号处理方法进行了对比,发现此方法优于基于希尔伯特变换的信号处理。
Brillouin optical time-domain reflectometer structure of the Brillouin scattering distributed optical fiber sensor detects spontaneous scattered light, the signal is very weak, and the band at tens of megahertz above, it is difficult to apply the ordinary coherent demodulation method. Aiming at the characteristics of the sensor signals, a coherent optical detection method based on Morlet wavelet transform is proposed. Firstly, the frequency-shifted reference light and spontaneous Brillouin scattering light are generated by microwave electro-optic modulation to detect coherently. The amplitude of the scattered light signal is demodulated by classical wavelet transform to obtain the Brillouin scattering light signal with improved signal-to-noise ratio. The results of numerical simulation and experimental data processing are given. The results show that the classical wavelet transform can process Brillouin optical time-domain reflectometer signal well. Compared with the Hilbert transform based sensing signal processing method, this method is found to be superior to Hilbert transform based signal processing.