面向XFEL的km级光纤链路的fs精度时钟分布

Femtosecond precision timing distribution over km level stabilized fiber link for application in XFEL

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2km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2h内的时钟分布稳定度优于10-18,时钟延迟标准差为1.1fs。

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 2km 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 1.1fs over 2hobservation,and the time stability is better than 10-18.