Optical frequency combs were developed nearly two decades ago to support the world's
most precise atomic clocks. Acting as precision optical synthesizers, frequency combs …

Ultra-precise timing has become a prerequisite for many modern large-scale scientific
instruments, and timing precision is a crucial enabling factor to achieve the ultimate goals of …

The combination of optical time transfer and optical clocks opens up the possibility of large-
scale free-space networks that connect both ground-based optical clocks and future space …

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 …

The large-scale clock network is the key ingredient to obtain high precision in many
scenarios, from fundamental research to cutting-edge applications. The advantage of the …

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 …

We demonstrate carrier-phase optical two-way time-frequency transfer (carrier-phase
OTWTFT) through the two-way exchange of frequency comb pulses. Carrier-phase OTWTFT …

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 …

We demonstrate real-time, femtosecond-level clock synchronization across a low-lying,
strongly turbulent, 12-km horizontal air path by optical two-way time transfer. For this long …

Single-cavity, dual-comb lasers are those specially designed mode-locked lasers that can
emit more than one, asynchronous ultrashort pulse trains with stable repetition frequency …