Optical frequency transfer over submarine fiber links

Abstract

Bidirectional phase-stabilized optical fiber links allow state-of-the-art optical clocks to be compared on a continental scale.However, intercontinental comparisons are still based on satellite techniques, preventing optical clocks from being compared without degradation.We performed the first optical frequency transfer experiment over submarine links, measuring levels of environmentally induced noise substantially lower than for on-land links.From these measurements, we predict the transfer stability that can be achieved over transoceanic links.We also performed the first optical frequency transfer over fibers installed in power cables, observing optical perturbations caused by the high-voltage field.Finally, we show that the low background noise of fibers on the seafloor allows applications in geophysical sensing.