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arXiv · 1808.07040

Femtosecond Optical Two-Way Time-Frequency Transfer in the Presence of Motion

Laura C. Sinclair·Hugo Bergeron·William C. Swann·Isaac Khader·Kevin C. Cossel·Michael Cermak·Nathan R. Newbury·Jean-Daniel Deschênes
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Abstract

Platform motion poses significant challenges to high-precision optical time and frequency transfer. We give a detailed description of these challenges and their solutions in comb-based optical two-way time and frequency transfer (O-TWTFT). Specifically, we discuss the breakdown in reciprocity due to relativity and due to asynchronous sampling, the impact of optical and electrical dispersion, and velocity-dependent transceiver calibration. We present a detailed derivation of the equations governing comb-based O-TWTFT in the presence of motion. We describe the implementation of real-time signal processing algorithms based on these equations and demonstrate active synchronization of two sites over turbulent air paths to below a femtosecond time deviation despite effective velocities of +/-25 m/s, which is the maximum achievable with our physical setup. With the implementation of the time transfer equation derived here, we find no velocity-dependent bias between the synchronized clocks to within at two-sigma statistical uncertainty of 330 attoseconds.

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Laura C. Sinclair, Hugo Bergeron, William C. Swann, Isaac Khader, Kevin C. Cossel, Michael Cermak, Nathan R. Newbury, Jean-Daniel Deschênes. 2018-08-21. Femtosecond Optical Two-Way Time-Frequency Transfer in the Presence of Motion. https://doi.org/10.1103/physreva.99.023844

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