Time Synchronization over a Free-Space Optical Communication Channel
Isaac H. Khader, Laura C. Sinclair, William C. Swann, Hugo Bergeron, Nathan R. Newbury, Jean-Daniel Deschenes
Free space optical (FSO) communication channels are typically used to transmit high-speed data between sites over the air. Here we repurpose an FSO digital communication system and use it directly for two-way time transfer. We demonstrate real-time synchronization between two sites over a turbulent air path of 4 km using binary phase modulated CW laser light. Under synchronization, the two sites exhibit a fractional frequency deviation below 10u^-15 and a time deviation below 1 picosecond at one-hour averaging time. Over an 8-hour period the peak to peak wander is 16 ps.
, Sinclair, L.
, Swann, W.
, Bergeron, H.
, Newbury, N.
and Deschenes, J.
Time Synchronization over a Free-Space Optical Communication Channel, Optica, [online], https://doi.org/10.1364/OPTICA.5.001542
(Accessed August 3, 2021)