Abstract
To compare the increasing number of optical frequency standards, highly stable optical signals have to be transferred over continental distances. We demonstrate optical-frequency transfer over a 1840-km underground optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of for a gate time of 1 s reaching in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about . The spectral noise distribution of our fiber link at low Fourier frequencies leads to a slope in the modified Allan deviation, which is also derived theoretically.
- Received 17 May 2013
DOI:https://doi.org/10.1103/PhysRevLett.111.110801
© 2013 American Physical Society
Synopsis
Cross-Country Time Keeping
Published 12 September 2013
A new distance record is set in the fiber transmission of stable frequency signals capable of synchronizing atomic clocks.
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