提出了一种基于双光束干涉的分布式光纤振动传感器，利用双路瑞利散射信号的干涉效应探测振动信号并利用传统的光时域反射计定位原理进行定位。基于该原理提出一种新的信号处理方案，在传统移动平均算法的基础上引入间隔参数并对信号进行标准化处理，不仅可以降低系统运算量，而且能去除因干涉灵敏度升高造成的本底噪声影响，提高振动信号的信噪比。实验结果表明，该系统可以有效探测到外界扰动信号并进行精确定位,而且探测灵敏度较高。当传感光纤长度为5 km时，系统空间分辨率可以达到20 m，信噪比约为8.5 dB。该系统可以用于管道安全预警和周界安防以及结构健康监测等领域。

A distributed vibration sensor based on two-beam interference is proposed and experimentally demonstrated. Optical pulses are launched into two distributed fibers. With the interference effect of two channel Rayleigh scattering signals and the positioning principle of conventional optical time domain reflectometer (OTDR), detection and location of vibration events along sensing fibers can be achieved. A new signal processing method is subsequently utilized to improve the signal-to-noise ratio (SNR) of the signal and reduce the system computation. Experimental results show that the system can effectively detect and precisely positioning the external vibration events with high sensitivity. A validated optimal spatial resolution of 20 m is acquired under testing fiber length of 5 km and the SNR of the differential signal can be as high as 8.5 dB. This new interferometer can be used for long distance monitoring such as pipeline security pre-warning as well as any vibration monitoring.