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.

中文翻译：

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海底光纤链路上的光频率传输

双向相位稳定的光纤链路允许在大陆范围内比较最新的光学时钟。但是，洲际比较仍然基于卫星技术，从而无法比较光学时钟而不会降低其质量。我们在海底链路上进行了第一个光学频率传输实验，测量的环境噪声水平明显低于陆上链路。根据这些测量，我们预测可以通过跨洋链接实现的传输稳定性。我们还对安装在电力电缆中的光纤进行了首次光学频率转换，观察了高压场引起的光学扰动。最后，我们证明了海底纤维的低背景噪声允许在地球物理感测中应用。