NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.

Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.

U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

PUBLICATIONS

Time Synchronization over a Free-Space Optical Communication Channel

Published

Author(s)

Isaac H. Khader, Laura C. Sinclair, William C. Swann, Hugo Bergeron, Nathan R. Newbury, Jean-Daniel Deschenes

Abstract

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.
Citation
Optica
Pub Type
Journals

Download Paper

DOI Link

Keywords

Optical communications, Metrology
Time and frequency metrology, Physics and Time and frequency

Citation

Khader, I. , Sinclair, L. , Swann, W. , Bergeron, H. , Newbury, N. and Deschenes, J. (2018), Time Synchronization over a Free-Space Optical Communication Channel, Optica, [online], https://doi.org/10.1364/OPTICA.5.001542 (Accessed October 7, 2025)

Issues

If you have any questions about this publication or are having problems accessing it, please contact [email protected].

Created December 20, 2018, Updated September 4, 2019
Was this page helpful?