Timescale comparison between optical atomic clocks over ground-to-space and terrestrial
free-space laser links will have enormous benefits for fundamental and applied sciences …

Improving and homogenizing time and space reference systems on Earth and, more
specifically, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1 mm and a …

Future optical clock networks will require free-space optical time-frequency transfer between
flying clocks. However, simple one-way or standard two-way time transfer between flying …

Distributed antenna arrays have been proposed for many applications ranging from space-
based observatories to automated vehicles. Achieving good performance in distributed …

Optical frequency combs have emerged as a new generation of metrological tools, driving
advancements in various fields such as free-space two-way time–frequency transfer, low …

We demonstrate frequency-comb-based optical two-way time-frequency transfer across a
three-node clock network. A fielded, bidirectional relay node connects laboratory-based …

With the demonstration of quantum-limited optical time transfer capable of tolerating the
losses associated with long ground-to-space links, two future applications of free-space time …

Geopotential and orthometric height differences between distant points can be measured via
timescale comparisons between atomic clocks. Modern optical atomic clocks achieve …

The next generation of space-based networks for communications, sensing, and navigation
will contain optical clocks embedded within satellites. To fully realize the capabilities of such …

We use frequency-comb-based optical two-way time-frequency transfer (O-TWTFT) to
measure the optical frequency ratio of state-of-the-art ytterbium and strontium optical atomic …