基于高频微波技术的分布式光纤传感器布里渊散射信号检测

分析了布里渊分布式光纤传感技术原理,采用自行研制的光纤单纵模分布反馈(DFB)激光器结合电光调制技术,利用相干检测技术,对布里渊微弱后向散射信号进行检测。通过改进滤波放大技术,对微弱后向散射光信号进行有效放大,再用扰偏技术及信号采样平均处理,实现对光纤传感器后向布里渊散射信号在11 GHz高频段直接采集显示。结果表明,探测所得布里渊散射信号峰值功率可达50 mV,能有效降低解调系统信号检测难度,改善了系统信噪比(SNR)。初步实验结果证明了该方案的可行性。

Detection of Spontaneous Brillouin Backscattered Power in Distributed Optical Fiber Sensor System Based on High Frequency Microwave Technology

The technique of Brillouin scattering distributed optical fiber sensing has been presented.Optical heterodyne detection was used to detect the weak Brillouin back scattering signal based on single longitudinal mode distributed feedback(DFB) laser and electric optical modulation technique.The scattering signal was amplified effectively by improving the filter and erbium doped fiber amplifier(EDFA).The 11 GHz radio-frequency(RF) signal of Brillouin back scattering is gathered and averaged.The experimental procedures and results are presented.The results show that the peak power of Brillouin back scattering at 11 GHz can reach 50 mV,and the intensity noise of light source induced the system's signal to noise ratio(SNR) decreased greatly,which reduced the difficulty of signal process in demodulation system.The experimental results confirm that the configuration is feasible.