Demonstrations of real-time precision optical time synchronization in a true three-node architecture

Abstract

Multi-node optical clock networks will enable future studies of fundamental physics and enable applications in quantum and classical communications as well as navigation and geodesy. We implement the first ever multi-node optical clock network with real-time, relative synchronization over free-space communication channels and precision on the order of 10 femtoseconds, realized as a three-node system in a hub-and-spoke topology. In this paper we describe the system and its performance, including a first ever measurement of precision optical time synchronization between nodes with no direct communication link or causal feedback relationship.

Keywords

• optical time transfer
• frequency combs
• optical clocks