We have reported the reported the world’s first Very Long Baseline Interferometry (VLBI) radio observation where the VLBI station was synchronized to our strontium optical lattice clock via a stabilized, long-distance fibre-optic link.

You can see the paper here: https://doi.org/10.1051/0004-6361/201730615

The quality of Very Long Baseline Interferometry (VLBI) radio observations predominantly relies on precise and ultra-stable time and frequency (T&F) standards, usually hydrogen masers (HM), maintained locally at each VLBI station. We presented an operational solution in which the VLBI observations are routinely carried out without use of a local HM, but using remote synchronization via a stabilized, long-distance fibre-optic link. The T&F reference signals, traceable to international atomic timescale (TAI), are delivered to the VLBI station from a dedicated timekeeping laboratory. Moreover, we described a proof-of-concept experiment where the VLBI station was synchronized to a remote strontium optical lattice clock during the observation.