Optical frequency transfer via an ultra-stable open-air short link

Abstract

The 17 m atmospheric link for ultrastable optical frequency transfer is developed. The frequency instability induced by atmospheric fluctuations is reduced by more than 20 times with the help of active compensation system and reaches 2.3·10−18 at τ = 250 s. The link contribution to inaccuracy is reduced by 3 orders of magnitude and equals 1.3·10−20.