Two-photon assisted clock comparison to picosecond precision

TL;DR

This paper demonstrates a novel clock comparison method using two-photon correlations from quantum light sources, achieving synchronization precision of around 64 picoseconds and analyzing hardware effects on performance.

Contribution

The study introduces a two-photon assisted clock comparison scheme that enhances synchronization precision to tens of picoseconds, incorporating analysis of hardware impact.

Findings

Achieved 64 ps clock synchronization precision.

Identified detector jitter and noise as performance degraders.

Demonstrated potential for remote clock synchronization at tens of picoseconds.

Abstract

We have experimentally demonstrated a clock comparison scheme utilizing time-correlated photon pairs generated from the spontaneous parametric down conversion process of a laser pumped beta-barium borate crystal. The coincidence of two-photon events are analyzed by the cross correlation of the two time stamp sequences. Combining the coarse and fine part of the time differences at different resolutions, a 64 ps precision for clock synchronization has been realized. We also investigate the effects of hardware devices used in the system on the precision of clock comparison. The results indicate that the detector's time jitter and the background noise will degrade the system performance. With this method, comparison and synchronization of two remote clocks could be implemented with a precision at the level of a few tens of picoseconds.