G.A. Vishnyakova¹, K.S. Kudeyarov¹, K.Yu. Khabarova^1,2, N.N. Kolachevsky^1,3

¹P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow
²FSUE «VNIIFTRI», Moscow region
³Russian Quantum Center, Innovation Center Territory «Skolkovo», Moscow
gulnarav7@gmail.com

Al’manac of Modern Metrology № 4 (24) 2020, pages 47–64

Today, the fractional instability of atomic optical clocks has reached the record eighteen-digit level, two orders of magnitude better than for cesium fountains representing the primary frequency standard. This is paralleled by the development of techniques for transferring accurate time and optical frequency signals, including fiber links. With this technology, the fractional instability of transferred frequency can be lowered to below 10^-18 with an averaging time of 2000 s for a 1000 km optical link that allows for chronometric levelling experiments at and below the cm-level. The new PTB-MPQ fiber link and its application for optical clock comparison are described.

Key words: ultrastable frequency transfer, optical fiber links, femtosecond laser, frequency stabilization.

Full texts of articles are available only in Russian in printed issues of the magazine.