Department News

Prof. KIM, Seung-Woo and Prof. KIM, Young-Jin research team, Free-space transfer of comb-rooted optical frequencies over an 18 km open-air link

관리자 2019.10.04


<Prof. KIM, Seung-Woo(left), Prof. KIM, Young-Jin(right)>

The research team led by Professor Seung-Woo Kim and Young-Jin Kim in Department of Mechanical Engineering demonstrated a near-infrared frequency-comb-rooted scheme of transferring multiple lasers concurrently over an 18 km open-air optical link. The lasers were generated from a frequency comb having hundreds of millions optical lasers, in stabilization to a high-finesse cavity which is frequency standard with a narrow linewidth of 1.5 Hz at 1 s integration. The optical link is built long enough to simulate the turbulence effect encountered over the troposphere in ground-to-satellite transmissions. The concurrent transfer of multiple comb-rooted lasers is intended for long distance delivery of not just individual lasers but also microwaves that are synthesized by paring different lasers bound with high inter-comb-mode coherence. The proposed free-space transfer of comb-rooted lasers and microwave generations is expected to facilitate many photonic applications such as atomic clock dissemination, fundamental constants measurements, long-baseline interferometers, and massive coherent optical communications on a global scale. The result was published on September 30 in Nature Communications in recognition of its excellence.