Frequency Transfer in Electronically Stabilized Fiber Optic Link Exploiting Bidirectional Optical Amplifiers

In this paper, we present the experimental result for the fiber optic frequency transfer link with optical regenerators exploiting the same Er-doped fiber for amplifying the signals in both directions. The measurements performed at the distance of 124 km with one amplifier and 224 km with three amplifiers showed that the presented solution is adequate for transferring the frequency signals generated by cesium clocks, hydrogen masers, and cesium fountain clocks. The Allan deviation around 9 ·10^-18 and 5.5 ·10^-17 was found for the averaging time of 10⁵ s for 124- and 224-km-long links, respectively.