We propose and experimentally demonstrate a plug-and-play, practical, and enabling method allowing to synchronise the building blocks of a quantum network in an all-optical way. Our scheme relies on mature and reliable classical telecommunication and non-linear optical technologies, and can be implemented in a universal way with off-the-shelf components. Compared to already reported solutions, it allows achieving high-quality synchronisation compatible with high network-operation rate and is free from opto-electronic jitters affecting servo-loop-based configurations. We test our scheme with a genuine quantum optical method in terms of the interference between two photons coming from two remotely synchronised sources spaced by distances of up to 100 km. Measured visibilities well above 90% confirm the validity of our approach. Due its simplicity and high-quality performance, our scheme paves the way for the synchronisation of long-distance quantum networks based on fibre, free-space, as well as hybrid solutions.

我们提出并通过实验演示了一种即插即用，实用且启用的方法，该方法允许以全光方式同步量子网络的构建块。我们的方案依赖于成熟可靠的经典电信技术和非线性光学技术，并且可以采用现成的组件以通用方式实施。与已报告的解决方案相比，它可以实现与高网络运行速率兼容的高质量同步，并且不会影响基于伺服环路的配置的光电抖动。我们用一种真正的量子光学方法对我们的方案进行了测试，它是对来自两个遥远同步光源（相距不超过100 km）的两个光子之间的干扰的。测得的可见度远高于90％，证实了我们方法的有效性。