提出了应用于周界安防的基于后向瑞利散射光空间差分干涉的光纤分布式振动传感监测方案。环境振动信号引起传感光纤的相位变化, 含有相位信息的后向瑞利散射信号注入到非平衡迈克尔逊干涉仪, 实现了后向瑞利散射信号的空间差分干涉, 光纤分布式振动传感监测完成相位信号的解调, 提高了系统的灵敏度。该系统能够实时监测入侵者的行走路线和速率以及模拟挖掘的距离的判断, 实现了15 dB的信噪比以及35 m的探测距离。

A optical distributed vibration sensing(DVS) scheme based on the space difference of Rayleigh backscattering was presented for perimeter security. In this scheme Rayleigh backscattered light with phase changes induced by vibration signal along the sensing fiber was split and fed into an imbalanced Michelson interferometer. The space difference of Rayleigh backscattering was realized. The DVS system realized the phase demodulation of the Rayleigh backscattered light to improve the sensitivity of the system. The distributed vibration sensing system based on space difference of Rayleigh backscattering can restore the walking route, the velocity of the intruder and the distance of the simulative digger, and obtain the demodulated signal SNR of 15 dB and detection distance of 35 m.