CFEL, Hamburg, Germany
MIT, Cambridge, Massachusetts, USA
Next-generation photon-science facilities such as X-ray free-electron lasers (X-FELs)* and intense-laser beamline centers** are emerging world-wide with the goal of generating sub-fs X-ray pulses with unprecedented brightness to capture ultrafast chemical and physical phenomena with sub-atomic spatiotemporal resolution. The only obstacle preventing this long-standing scientific dream to come true is a high- precision timing distribution system*** synchronizing various microwave and optical sub-sources across multi-km distances which is required for seeded X-FELs and attosecond pump-probe experiments. Here, we present, for the first time, a synchronous laser-microwave network that will enable attosecond precision photon science facilities. By developing new ultrafast metrological timing devices and carefully balancing fiber nonlinearities and fundamental noise contributions, we have achieved timing stabilization of a 4.7 km fiber network with 580 attosecond precision over 52 hours. Furthermore, we have realized a complete laser-microwave network incorporating two mode-locked lasers and one microwave source with total 950 attosecond jitter integrated from 1 microsecond to 18 hours.
*J. Stohr, LCLS-II Conceptual Design Report. No. SLAC-R-978. (SLAC, 2011).
**G. Mourou, T. Tajima, Optics & Photonics News 22, 47 (2011).
***J. Kim, et al., Nat. Photonics 2(12), 733-736 (2008).
