光缆维护时存在着故障点的位置定位不精确的问题,给光缆维护和抢修带来了困难。为解决这一问题提出了基于光时域反射仪(Optical Time Domain Reflectometer,OTDR)的光缆故障点精确定位方法。该方法结合了OTDR和偏振光时域反射技术(Polarization Optical Time Domain Reflectometry,POTDR),使用OTDR得到光缆故障点的光纤光学长度,利用POTDR分别获取光缆弯曲时和光缆恢复原状时的两组后向散射数据,用差值法和寻找斜率变化的方法对两组后向散射数据进行处理,可以确定光缆弯曲点的位置。结合光纤光学长度、弯曲点的位置及光缆余长系数,得出弯曲点与光缆故障点的距离,当弯曲点距离光缆故障点位置比较近时(小于200 m),对光缆故障点的定位很精确。实验结果表明,该方法能够精确地定位光缆故障点位置,结构简单,操作方便且不损伤光缆。

There is a problem of fault point inaccurate positioning in optical cable maintenance,bring difficulties to optical cable maintenance and repair.To solve this problem,optical cable fault point precise positioning method based on optical time domain reflectometer(OTDR) is proposed.The method combines OTDR with polarization optical time domain reflectometry (POTDR),uses OTDR to get the optical fiber length of fiber optical cable fault point,uses POTDR to obtain two sets of backscattering data respectively when fiber optic cable is bent and optical fiber cable is restored to its original state.Two sets of backscatter data are processed to determine the location of the flex point of the cable.The distance between the bending point and the cable fault point is obtained by combining the optical fiber length,the position of the bending point and the cable excess length coefficient.When the bending point is relatively close to the fault point(less than 200 meters),the location of the fault point accurate.Experimental results show that this method can accurately locate the position of the cable fault point,has the advantages of simple structure,convenient operation and no damage to the optical cable.