为了克服传统调制相移法测量频率范围窄、测量准确度低的缺点, 提出一种基于调制相移法的单模光纤长度精确测量技术.利用一体化矢量网络分析仪的高速调制信号同步技术及高频信号相位差测量技术, 设计并研制了单模光纤长度测量装置.基于矢量网络分析仪自带的VBA插件编写了自动控制及数据处理软件, 给出了相位变化量自动处理方法.利用研制的装置分别测量了长度为2 km、40 km和150 km的单模光纤在不同工作波长点的长度值, 实验结果表明, 2 km的光纤长度测量值实验标准偏差优于0.2 mm, 150 km的光纤长度测量值实验标准偏差接近0.01 m.该装置可对1 310 nm、1 490 nm以及1 550 nm波长的光纤距离进行精确测量, 为光纤长度的高准确度测量提供了一种新的技术途径.

In order to overcome the defect of narrow frequency band and low accuracy exist in the traditional modulation phase shift method, a single mode fiber length measurement technique based on modulation phase shift method was proposed. The single mode fiber length measuring device was designed and developed using the high-speed modulation signal synchronization and high-frequency signal phase difference mearuring technology in the integrated vector network analyzer. An auto-control and data processing software based on VBA plug-in of vector network analyzer was complicated, then an automatic processing method of phase variation was illustrated. Single mode fibers with the length of 2 km, 40 km and 150 km weretested using the developeddevice at different wavelengths, the results show that the standard deviation of 2 km fiber length measuring value is better than 0.2 mm, and the standard deviation of 150 km fiber length measuring value is close to 0.01 m. The fiber distance can be precisionly measured by this device at 1 310 nm, 1 490 nm and 1 550 nm.The proposed device can be expected to provide a new technical approach for precisionly measuring of fiber length.