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تسجيل مستخدم جديدOptical frequency transfer via 146 km fiber link with 10^{-19} relative accuracy
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We demonstrate the long-distance transmission of an ultra-stable optical frequency derived directly from a state-of-the-art optical frequency standard. Using an active stabilization system we deliver the frequency via a 146 km long underground fiber link with a fractional instability of 3*10^{-15} at 1 s, which is close to the theoretical limit for our transfer experiment. The relative uncertainty for the transfer is below 1*10^{-19} after 30 000 seconds. Tests with a very short fiber show that noise in our stabilization system contributes fluctuations which are two orders of magnitude lower, namely 3*10^{-17} at 1 s, reaching 10^{-20} after 4000 s.
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