M-Z干涉型传感技术在光缆定位方法中的应用

Application of M-Z Interferometric Sensing Technology in Cable Localization Method

光缆线路定位是铁路工程进行光缆线路施工、安装和检修的一项主要前提工作,研究光缆线路的定位方法具有重要意义。目前铁路上主要采用的定位方法有基于Sagnac干涉原理的双纤定位方法和基于菲涅耳反射原理的OTDR定位方法。本文提出的光缆线路定位方法以M-Z干涉型光纤传感技术为理论基础,通过分析外界振动源引起的相位变化,对该相位信号进行解调。利用傅里叶变换过程获得振动源信号位置与频谱图中第一零频点之间的关系,通过分析第一零频点,确定光缆线路上的振动源信号位置,实现结构简单、性能较好的光缆线路定位。试验结果显示,该定位系统能够以不超过42m的误差对振动源进行定位。

As the localization of optical fiber cable line is a precondition for the construction, installation and maintenance of optical fiber cable lines for railway project, it is of great significance to study the methods of fi-ber optic cable localization. Currently, the main localization methods used in railway are the dual-fiber locali-zation method based on Sagnac principle and OTDR based on Fresnel reflection principle. The method of opti-cal fiber cable locolization proposed in this paper was based on the M-Z interferometric optical fiber sensing technology. The phase signal was demodulated by analyzing the phase change caused by the external vibration source. The Fourier transform process was used to obtain the relationship between the position of the vibration source signal and the first space frequency point in the spectrogram. The position of the vibration source signal on the cable line was determined by analyzing the first null-frequency point, realizing the optical fiber cable lo-calization with the simple structure and better performance. The experimental results show that the system can determine the position of the vibration source signal with an error of no more than 42 m.