MIAO Xin-yu, ZHOU Bo, ZHOU Feng
(China Telecommunication Technology Labs, China Academy of Information and Communications Technology, Beijing 100191, China)
Abstract： A measurement method of optical fiber length using timestamp technique is demonstrated. Based on IEEE1588 precise clock synchronization protocol, the principle that time delay asymmetry on two path results in synchronization time deviation is used, and the difference between two-path delays could be deduced by measuring the synchronization time deviation reversely. Then the length of optical fiber on one path could be calculated if that on the other path is known. Due to the fact that the path of Sync and Delay_Req message is symmetric, the optical pulse dispersion and the asymmetry of photoelectric detector performance on two paths are averaged by exchanging two optical fibers. The time difference between master and slave clocks is eliminated by sharing the same time base. At last, the lengths of two single-mode optical fibers are measured with the uncertainty of 0.578 m for 3 227.722 m and 0.758 m for 25 491.522 m, respectively. Thus this method has high precision and long range.
Key words： timestamp; fiber length measurement; time synchronization
CLD number： TN25 Document code： A
Article ID： 1674-8042（2016）03-0302-05 doi： 10.3969/j.issn.1674-8042.2016.03.016
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基于时间戳技术的光纤长度精确测量方法
缪新育， 周 波， 周 峰
（中国泰尔实验室 中国信息通信研究院, 北京 100191）
摘 要: 本文提出了一种基于时间戳技术的光纤长度测量方法。 利用IEEE1588精密时间同步协议的线路时延不对称导致同步时间偏差的原理， 测量同步时间偏差， 反推线路时延差。 并通过一路已知长度的参考光纤， 计算得到被测光纤的长度。 同时利用时间同步协议的同步信号和延时请求信号测量机理对称的特点， 交换来回两线路上的光纤， 来均衡此两线路上光脉冲色散和光电探测器性能的不对称性。 将客户端和服务器至于同一时基， 来消除同步时间偏差中客户端和服务器时钟不一致的影响。 最后利用该方法测量了两根长度为3 227.722 m和25 491.522 m的单模光纤， 不确定度分别为0.578 m和0.758 m。 故此测量方法精度高且范围大。
关键词: 时间戳； 光纤长度测量； 时间同步
引用格式： MIAO Xin-yu, ZHOU Bo, ZHOU Feng. Precise measurement method of optical fiber length based on timestamp technique. Journal of Measurement Science and Instrumentation, 2016, 7(3)： 302-306.［doi： 10.3969／j.issn.1674-8042.2016.03.016］
