Calosso C E, Bertacco E, Calonico D, Clivati C, Costanzo G A, Frittelli M, Levi F, Mura A, Godone A
Opt Lett. 2014 Mar 1;39(5):1177-80. doi: 10.1364/OL.39.001177.
We performed a two-way remote optical phase comparison on optical fiber. Two optical frequency signals were launched in opposite directions in an optical fiber and their phases were simultaneously measured at the other end. In this technique, the fiber noise is passively canceled, and we compared two optical frequencies at the ultimate 10(-21) stability level. The experiment was performed on a 47 km fiber that is part of the metropolitan network for Internet traffic. The technique relies on the synchronous measurement of the optical phases at the two ends of the link, which is here performed by digital electronics. This scheme offers some advantages with respect to active noise cancellation schemes, as the light travels only once in the fiber.
我们在光纤上进行了双向远程光学相位比较。两个光频信号在光纤中沿相反方向发射，并在另一端同时测量它们的相位。在这项技术中，光纤噪声被被动消除，并且我们在高达10^(-21)的极限稳定水平下比较了两个光频。实验在一条47公里长的光纤上进行，该光纤是城市互联网流量网络的一部分。该技术依赖于链路两端光学相位的同步测量，这里由数字电子设备完成。与有源噪声消除方案相比，该方案具有一些优势，因为光在光纤中仅传播一次。
