针对带延迟子环分布式光纤传感系统的多频率成分振动源定位的问题，提出一种只依赖于振动源任一频率成分的频域解调方法。建立了脉冲光两次经过延迟环的干涉光束输出方程，结合傅里叶变换，根据振动源任一振动频率分量及其对应的两次干涉输出幅度之间的关系计算了振动位置。在此基础上，将宽带激光超辐射发光二极管（中心波长为1550 nm）外接脉冲可调激励电源产生的脉冲光作为光源，采用普通单模光纤构建的10 km萨尼亚克环、2 km延迟子环以及光电转换器搭建了实验系统，进行了奔跑行为的侵入定位实验。结果表明当传感光纤总长度为10 km时，平均定位误差为78 m。

For the localization of multi-frequency vibration sources in the distributed fiber sensing system with a delay fiber loop, a frequency-demodulation method based on any one frequency component is presented. The equation of interference outputs which are generated after the pulses pass through delay fiber loop twice is expressed. According to the Fourier transform and the relationship between any one frequency component of the vibration sources and the amplitudes of the interference outputs, the vibration position can be determined. In experiment, a pulsed light source with 1550 nm center wavelength, a 10 km Sagnac ring consisted of normal single mode fiber, a 2 km delay sub-loop and a photoelectric converter are used to build the experimental system. The light source is generated from a broadband laser superluminescent diodes with an external tunable pulsed excitation power. The running intrusion is used as the vibration source. The results show that when the total length of the sensing fiber is 10 km, the average deviation of position localization is 78 m.