报道了一种基于光纤链路的飞秒精度的时钟分布方案。一台被动锁模的光纤飞秒激光器输出的超短脉冲序列作为主时序，通过2 km的普通单模光纤链路分发，利用平衡光学互相关技术探测传输中积累的时钟延迟误差，由光纤拉伸器和步进电机相结合在本地主动补偿，在2 h内的时钟分布稳定度优于10-18，时钟延迟标准差为1.1 fs。

This paper demonstrates a fiber link based timing distribution with femtosecond precision. The output femtosecond laser pulse train from a passively mode-locked fiber laser serves as master clock, which is distributed over a 2 km single mode fiber link. A balanced optical cross-correlator (BOC) is used to monitor the accumulated timing error, which is actively compensated by a local fiber stretcher and a step motor. The standard deviation of the residual timing error is less than 1.1 fs over 2 h observation, and the time stability is better than 10-18.