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

Published

February 22, 2019

Author(s)

Laura C. Sinclair, Hugo Bergeron, William C. Swann, Isaac H. Khader, Kevin C. Cossel, Michael A. Cermak, Nathan R. Newbury, Jean-Daniel Deschenes

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 velocity 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 the statistical uncertainty of 330 attoseconds.

Citation

Physical Review A

Pub Type

Journals

Keywords

time transfer, optical clocks, optical two-way time-frequency transfer, frequency combs

Citation

Sinclair, L. , Bergeron, H. , Swann, W. , Khader, I. , Cossel, K. , Cermak, M. , Newbury, N. and Deschenes, J. (2019), Femtosecond Optical Two-Way Time-Frequency Transfer in the Presence of Motion, Physical Review A (Accessed October 7, 2025)