开展了基于光纤后向相干瑞利散射原理的分布式光纤传感在管道安 全实时监测系统中的信号数值模拟和实验研究。 采用多个连续脉冲周期光纤相干后向瑞利散射光在有扰动情况的一维脉冲响应理论模型, 解释了外部扰动对整个后向 瑞利散射信号的影响。并且对理论模型进行数值模拟, 直观展示了相干后向瑞利散射光功率关系曲线;通过对4 km长度的 光纤进行扰动传感实验, 有效地定位了扰动的发生;并且提出了一种利用软件寻峰归一化 提高后向瑞利散射功率信号信噪比的方法, 可以减少平均次数, 从而增大可提取扰动频率范围。

Preliminary investigation for pipeline safety real-time monitoring with distributed fiber optic sensing technique based on coherent Rayleigh backscattering was carried out. On the basis of a novel one-dimensional impulse-response model of coherent Rayleigh backscattering in fiber, the influence of backscattering power curve with multiple continuous input pulses under external disturbance was explained. Coherent Rayleigh backscattering light power curve was visually presented through numerical simulations with the theoretical model. In order to demonstrate the model, an experimental measurement with 4 km-long single-mode sensing fiber was performed and the position where the disturbance occurs was easily found. To improve the SNR, a normalization method of peak-seeking with software was introduced. This method can effectively reduce average number and enhance the maximum detectable frequency range of external disturbance.