中文摘要：

采用一种基于Sagnac干涉仪原理的分布式光纤声学传感系统对长距离管道泄漏进行检测，主要分析和研究了不同的输入偏振态对输出光功率的影响．当信号光场与本振光场的偏转态一致时，可得到高灵敏度接收；当信号光场和本振光场的偏振态正交时，检测不到泄漏信号．在系统长度10．044km时，测得的零点频率是在20kHz，根据理论公式计算的泄漏点位置在5km处，与实际的泄漏点的位置5．022km处，比较相近，相对误差为0．44％．

英文摘要：

A measurement of the leakage position in a distributed optical fiber acoustic sensor system based on Sagnac interferometer is clemonstrated. The effect of the input polarization on the output power of the demodulated signal is researched theoretically and experimentally. The influence of the polarization of the signal and the reference on the measurement sensitivity is calculated. Theoretical analysis and experimental simulation are carried out. The results show that, when the system is 10. 044 km long, the least frequency measured is 20 kHz and the calculated leakage position is 5 km, which is close to the real leakage position of 5. 022 kin. The relative difference is 0. 44%.