中文摘要：

提出一种基于3×3迈克耳孙干涉仪的分布式光纤振动传感系统，利用3×3干涉仪搭建零差相干检测的相位敏感型光时域反射计（φ-OTDR）。使用传输矩阵相位解调算法，通过对3×3迈克耳孙干涉仪的传输矩阵基本参数的求取，建立差分相位与干涉仪输出光强的对应关系，使用简单有效的软件运算程序对光纤中的瑞利散射光的差分相位进行解调，实现对光纤的扰动进行分布式探测。利用该系统对光纤线路上的振动进行测试，实验结果表明，系统能够对振动进行准确的定位，并有效地对音频和射频驱动的频率进行还原，系统有效传感距离为10 km。

英文摘要：

A distributed fiber vibration sensor based on 3×3 Michelson interferometer is proposed, and a 3×3 interferometer is used to build the structure of a phase sensitive optical time domain reflectometer （φ-OTDR） based on homodyne coherent detection. With transfer matrix phase demodulation algorithm and through the basic parameters of the 3×3 interferometer transmission matrix, the corresponding relationship between differential phase and interferometer output light intensity is established. The simple and efficient software computing programs are used to demodulate the differential phase of Rayleigh scattering light in optical fiber, so as to realize the optical fiber distributed disturbance detection. The system is also used to detect the vibration along the fiber, and the experimental results show that the sensing system can accurately locate for the vibration and restore the frequencies of audio and radio frequency drivers, of which the effective sensing distance is 10 km.