Clock synchronization with pulsed single photon sources

Abstract

Photonic quantum technology requires precise, time-resolved identification of photodetection events. In distributed quantum networks with spatially separated and drifting time references, achieving high precision is particularly challenging. Here we build on recent advances of using single-photons for time transfer and employ and quantify a fast postprocessing scheme designed to pulsed single-photon sources. We achieve an average root mean square synchronization jitter of 3.0 ps and a stability comparable to systems with ultra-stable clocks (54 ps at 1 second integration time, in terms of Allan time deviation). Our algorithm compensates substantial clock imperfections from crystal oscillators, is superior for low signal scenarios, and allows the quantum communication networks to transmit data simultaneously to time transfer.