Absolute clock synchronization with a single time-correlated photon pair source over a 10 km optical fibre
Abstract
We demonstrate a point-to-point clock synchronization protocol based on bidirectionally propagating photons generated in a single spontaneous parametric down-conversion (SPDC) source. Tight timing correlations between photon pairs are used to determine the single and round-trip times measured by two separate clocks, providing sufficient information for distance-independent absolute synchronization secure against symmetric delay attacks. We show that the coincidence signature useful for determining the round-trip time of a synchronization channel, established using a 10 km telecommunications fiber, can be derived from photons reflected off the end face of the fiber without additional optics. Our technique allows the synchronization of multiple clocks with a single reference clock co-located with the source, without requiring additional pair sources, in a client-server configuration suitable for synchronizing a network of clocks.
- Publication:
-
Optics Express
- Pub Date:
- May 2022
- DOI:
- 10.1364/OE.455542
- arXiv:
- arXiv:2009.04815
- Bibcode:
- 2022OExpr..3018530L
- Keywords:
-
- Quantum Physics
- E-Print:
- 5 pages, 6 figures. arXiv admin note: text overlap with arXiv:1812.08450