Two-Way Optical Frequency Comparisons at 5x10^-21 relative stability Over 100km Telecommunication Network Fibers

Anthony Bercy (1, 2, 3) , Fabio Stefani (1, 2, 3) , Olivier Lopez (1, 3) , Christian Chardonnet (1, 3) , Paul-Eric Pottie (2) , Anne Amy-Klein (1, 3)

1 MMTF
2 LNE - SYRTE - Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace
3 LPL - Laboratoire de Physique des Lasers

By using two-way frequency transfer, we demonstrate ultra-high resolution comparison of optical frequencies over a telecommunication fiber link of 100 km operating simultaneously digital data transfer. We first propose and experiment a bi-directional scheme using a single fiber. We show that the relative stability at 1 s integration time is 7 10^18 and scales down to 5 10^21. The same level of performance is reached when an optical link is implemented with an active compensation of the fiber noise. We also implement a real-time two-way frequency comparison over a uni-directional telecommunication network using a pair of parallel fibers. The relative frequency stability is 10^15 at 1 s integration time and reaches 2 10^17 at 40 000 s. The fractional uncertainty of the frequency comparisons was evaluated for the best case to 2 10^20. These results open the way to accurate and high resolution frequency comparison of optical clocks over intercontinental fiber networks.

Mots clés: frequency metrology; optical link; ultrastable frequency transfer; two-way

Domaines: Physique Quantique [quant-ph]

Anthony Bercy, Fabio Stefani, Olivier Lopez, Christian Chardonnet, Paul-Eric Pottie, et al.. Two-Way Optical Frequency Comparisons at 5x10^-21 relative stability Over 100km Telecommunication Network Fibers. Physical Review A, 2014, ⟨10.1103/PhysRevA.90.061802⟩. ⟨hal-01057013v2⟩