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Drift-free femtosecond timing synchronization of remote optical and microwave sources

Abstract

Femtosecond mode-locked lasers have revolutionized many fields of science and engineering1,2,3,4. Because of their ultralow noise5, it has been anticipated that mode-locked lasers would synchronize large-scale scientific facilities6,7,8,9 requiring extremely high timing accuracy. However, the lack of long-term stable synchronization techniques has hindered the realization of pervasive synchronization with such lasers. Here we present a comprehensive set of new techniques for long-term stable synchronization of optical and microwave sources over long distances. We use ultralow-noise optical pulse trains generated from mode-locked lasers as the timing signals, then distribute them by means of timing-stabilized fibre links and, finally, synchronize the delivered timing signals with the optical and microwave sources being targeted. Using these techniques, we demonstrate, for the first time, that remotely located lasers and microwave sources can be synchronized with less than 10-fs precision over more than 10 h. This drift-free operation is an important milestone in transitioning mode-locked laser-based synchronization from the laboratory into real-world facilities.

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Figure 1: Large-scale synchronization of optical and microwave sources.
Figure 2: Timing-stabilized fibre link.
Figure 3: Optical–optical synchronization.
Figure 4: Optical–microwave synchronization.

References

  1. Udem, T., Holzwarth, R. & Hänsch, T. W. Optical frequency metrology. Nature 416, 233–237 (2002).

    Article  ADS  Google Scholar 

  2. Ma, L.-S. et al. Optical frequency synthesis and comparison with uncertainty at the 10−19 level. Science 303, 1843–1845 (2004).

    Article  ADS  Google Scholar 

  3. Thorpe, M. J., Moll, K. D., Jones, R. J., Safdi, B. & Ye, J. Broadband cavity ringdown spectroscopy for sensitive and rapid molecular detection. Science 311, 1595–1599 (2006).

    Article  ADS  Google Scholar 

  4. Diddams, S. A., Hollberg, L. & Mbele, V. Molecular fingerprinting with the resolved modes of a femtosecond laser frequency comb. Nature 445, 627–630 (2007).

    Article  Google Scholar 

  5. Haus, H. A. & Mecozzi, A. Noise of mode-locked lasers. IEEE J. Quantum Electron. 29, 983–996 (1993).

    Article  ADS  Google Scholar 

  6. Arthur, J. et al. Linac Coherent Light Source (LCLS), conceptual design report SLAC-R593 (Stanford, 2002), at http://www-ssrl.slac.stanford.edu/lcls/cdr.

  7. Altarelli, M. (eds) et al. XFEL: The European X-Ray Free-Electron Laser, technical design report DESY 2006-097 (DESY, Hamburg, 2007), at http://xfel.desy.de.

    Google Scholar 

  8. Bocchetta, C. J. et al. FERMI@Elettra, conceptual design report ST/F-TN-07/12 (Trieste, 2007), at http://www.elettra.trieste.it/FERMI/.

  9. Cliché, J.-F. & Shillue, B. Precision timing control for radioastronomy. IEEE Control Sys. Mag. 26, 19–26 (2006).

    Google Scholar 

  10. Foreman, S. M., Holman, K. W., Hudson, D. D., Jones, D. J. & Ye, J. Remote transfer of ultrastable frequency references via fibre networks. Rev. Sci. Instrum. 78, 021101 (2007).

    Article  ADS  Google Scholar 

  11. Coddington, I. et al. Coherent optical link over hundreds of metres and hundreds of terahertz with subfemtosecond timing jitter. Nature Photon. 1, 283–287 (2007).

    Article  ADS  Google Scholar 

  12. Newbury, N. R., Williams, P. A. & Swann, W. C. Coherent transfer of an optical carrier over 251 km. Opt. Lett. 32, 3056–3058 (2007).

    Article  ADS  Google Scholar 

  13. Shelton, R. K. et al. Subfemtsecond timing jitter between two independent, actively synchronized, mode-locked lasers. Opt. Lett. 27, 312–314 (2002).

    Article  ADS  Google Scholar 

  14. Ma, L. S. et al. Frequency uncertainty for optically referenced femtosecond laser frequency combs. IEEE J. Quantum Electron. 43, 139–146 (2007).

    Article  ADS  Google Scholar 

  15. Wilcox, R. B. & Staples, J. W. Systems design concepts for optical synchronization in accelerators, in Proceedings of Particle Accelerator Conference (IEEE, 2007).

  16. Kim, J., Chen, J., Cox, J. & Kärtner, F. X. Attosecond-resolution timing jitter characterization of free-running mode-locked lasers. Opt. Lett. 32, 3519–3521 (2007).

    Article  ADS  Google Scholar 

  17. Chen, J., Sickler, J. W., Ippen, E. P. & Kärtner, F. X. High repetition rate, low jitter, low intensity noise, fundamentally mode-locked 167 fs soliton Er-fibre laser. Opt. Lett. 32, 1566–1568 (2007).

    Article  ADS  Google Scholar 

  18. Wilken, T. et al. Low phase noise 250 MHz repetition rate fibre fs laser for frequency comb applications, in Conference on Lasers and Electro-Optics (CLEO) CMR3 (OSA/IEEE LEOS, 2007).

  19. MenloSystems GmbH, M-series femtosecond fibre lasers from MenloSystems GmbH, at http://www.menlosystems.com/cfiber.html.

  20. Kim, J. et al. Long-term femtosecond timing link stabilization using a single-crystal balanced cross-correlator. Opt. Lett. 32, 1044–1066 (2007).

    Article  ADS  Google Scholar 

  21. Ivanov, E. N., Diddams, S. A. & Hollberg, L. Study of the excess noise associated with demodulation of ultra-short infrared pulses. IEEE Trans Ultrason. Ferroelectr. Freq. Control 52, 1068–1074 (2005).

    Article  Google Scholar 

  22. Ivanov, E. N., Diddams, S. A. & Hollberg, L. Noise properties of microwave signals synthesized with femtosecond lasers. IEEE Trans Ultrason. Ferroelectr. Freq. Control 54, 736–745 (2007).

    Article  Google Scholar 

  23. Shelton, R. K. et al. Phase-coherent optical pulse synthesis from separate femtosecond lasers. Science 293, 1286–1289 (2001).

    Article  ADS  Google Scholar 

  24. Schibli, T. R. et al. Attosecond active synchronization of passively mode-locked lasers using balanced cross-correlation. Opt. Lett. 28, 947–949 (2003).

    Article  ADS  Google Scholar 

  25. McFerran, J. J. et al. Low-noise synthesis of microwave signals from an optical source. Electron. Lett. 41, 650–651 (2005).

    Article  Google Scholar 

  26. Bartels, A. et al. Femtosecond-laser-based synthesis of ultra-stable microwave signals from optical frequency references. Opt. Lett. 30, 667–669 (2005).

    Article  ADS  Google Scholar 

  27. Kim, J., Kärtner, F. X. & Perrott, M. H. Femtosecond synchronization of radio frequency signal with the optical pulse trains. Opt. Lett. 29, 2076–2078 (2004).

    Article  ADS  Google Scholar 

  28. Kim, J., Kärtner, F. X. & Ludwig, F. Balanced optical–microwave phase detectors for optoelectronic phase-locked loops. Opt. Lett. 31, 3659–3661 (2006).

    Article  ADS  Google Scholar 

  29. Kim, J., Ludwig, F., Felber, M. & Kärtner, F. X. Long-term stable microwave signal extraction from mode-locked lasers. Opt. Express 15, 8951–8959 (2007).

    Article  ADS  Google Scholar 

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Acknowledgements

The authors appreciate many discussions with D. Moncton, W. Graves, M. Ferianis, H. Schlarb, S. Milton and J. Bisognano on the timing requirements for future FELs that motivated this work. We also thank F. Wong for the PPKTP design and M. Perrott for joint work on optoelectronic phase-locked loops. We acknowledge T. Schibli for his early work on laser synchronization and A. Winter, F. Ö. Ilday, Z. Zhang, F. Loehl and F. Ludwig for their early-stage contributions to fibre link stabilization and microwave extraction. This work was supported by the following agencies: the European Union, under the EuroFEL program; the US Office of Naval Research (ONR), under the Multidisciplinary University Research Initiative (MURI) program; the US Air Force Office of Scientific Research (AFOSR); the US Defense Advanced Research Projects Agency (DARPA); and the University of Wisconsin. J.K. acknowledges a doctoral fellowship from the Samsung Scholarship Foundation.

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Correspondence to Jungwon Kim or Franz X. Kärtner.

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Kim, J., Cox, J., Chen, J. et al. Drift-free femtosecond timing synchronization of remote optical and microwave sources. Nature Photon 2, 733–736 (2008). https://doi.org/10.1038/nphoton.2008.225

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