Perrott, M. H.
(Michael Perrott)

TUAOS03 Large-Scale Timing Distribution and RF-Synchronization for FEL Facilities
Jung-Won Kim, Fatih Oemer Ilday, Franz Kaertner, Oliver Muecke, Michael Perrott (MIT, Cambridge, Massachusetts), William S Graves, David Moncton, Townsend Zwart (MIT/BLAC, Middleton, Massachusetts)

For future advances in accelerator physics in general and seeding of FELs in particular, precise synchronization between seed radiation, low-level RF-systems and photo-injector laser is required. Typical synchronization methods based on direct photodetection are limited by the detector nonlinearities, which lead to amplitude-to-phase conversion and introduce timing jitter. A new synchronization scheme for extraction of low jitter RF-signals from optical pulse trains distributed by mode-locked lasers is proposed. It is robust against photodetector nonlinearities. The scheme is based on a transfer of timing information into an intensity imbalance between the two output beams from a Sagnac-loop interferometer. As a first experimental demonstration, sub-100 fs timing jitter between the extracted 2 GHz RF-signal and the 100 MHz optical pulse train from a mode-locked Ti:sapphire laser is demonstrated. Numerical simulations show that scaling to sub-femtosecond precision is possible. Together with mode-locked fiber lasers and timing stabilized fiber-link, this scheme can be applied for the large-scale precise timing distribution and synchronization of free-electron laser facilities.