Optical frequency transfers between ISI CAS and CESNET

摘要

Optical fiber links in Europe are with growing importance utilized in comparison campaigns of experimental optical clocks to verify their ultimate relative stability. We present a 306 km long optical fiber link established in the Czech Republic between ISI CAS Brno and CESNET Prague. This link will to deliver stable optical frequencies from laser standards located at ISI CAS in Brno to prospective academic and industrial partners in the Prague area. Our contribution reports on the current state of the fiber link for phase-coherent transfer of optical frequency. The long-haul link operates on an internet communication fiber in a dedicated 1540-1546nm DWDM window. A narrow-linewidth laser (Koheras BASIK) working at 1540.5 nm locked to a high-finesse optical cavity (Q = 300 000) serves as the optical frequency standard and source of highly coherent laser light at the transmitting side.