Two-Way Optical Frequency Comparisons Over 100km Telecommunication Network Fibers (1408.4989v1)
Abstract: 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 1018 and scales down to 5 1021. 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 1015 at 1 s integration time and reaches 2 1017 at 40 000 s. The fractional uncertainty of the frequency comparisons was evaluated for the best case to 2 1020. These results open the way to accurate and high resolution frequency comparison of optical clocks over intercontinental fiber networks.