Author: Yan, M.
Paper Title Page
TUOANO02 Long-term Stable, Large-scale, Optical Timing Distribution Systems With Sub-femtosecond Timing Stability 156
 
  • M.Y. Peng, P.T. Callahan, F.X. Kaertner, A.H. Nejadmalayeri
    MIT, Cambridge, Massachusetts, USA
  • K. Ahmed, S. Valente, M. Xin
    DESY, Hamburg, Germany
  • P. Battle, T.D. Roberts
    AdvR, Inc., Montana, USA
  • J.M. Fini, L. Grüner-Nielsen, E. Monberg, M. Yan
    OFS Laboratories, New Jersey, USA
  • F.X. Kaertner
    CFEL, Hamburg, Germany
 
  Funding: US Department of Energy Contract DE-SC0005262 and Center for Free-Electron Laser Science, DESY, Hamburg
Sub-fs X-ray pulse generation in kilometer-scale FEL facilities will require sub-fs long-term timing stability between optical sources over kilometer distances. We present here key developments towards a completely fiber-coupled, sub-fs optical timing distribution system. Our approach [*] is to lock a femtosecond pulsed laser to a microwave reference and distribute its pulse train through fiber links stabilized by balanced optical cross-correlators (BOCs) [**]. First, we verified that low-noise optical master oscillators for sub-fs timing distribution are available today; the measured jitter for two commercial femtosecond lasers is less than 70 as for frequencies above 1 kHz. Second, we developed a novel 1.2 km dispersion-compensated, polarization-maintaining fiber link to eliminate drifts induced by polarization mode dispersion. Link stabilization for 16 days showed 0.6 fs RMS timing drift and during a 3-day interval only 0.13 fs drift. Lastly, we fabricated a hybrid-integrated BOC using PPKTP waveguides [***] to eliminate alignment drifts and to reduce the link operation power by a factor of 10-100, which will reduce timing errors induced by fiber nonlinearities.
* J. Kim et al., Nat. Photon., 2, 12, 733–736, 2008.
** J. Kim et al., Opt. Lett., 32, 9, 1044–1046, 2007.
*** A. H. Nejadmalayeri et al., Opt. Lett., 34, 16, 2522–2524, 2009.
 
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