Fiber-laser-based clockwork for long-term measurements and comparisons of visible optical frequency standards

A long-term clockwork capable of linking visible optical frequency standards to the radio frequency domain is demonstrated with a continuous measurement stretching eight days. The clockwork is based on a femtosecond fiber laser frequency comb. Using this system, an uncorrected measurement of the \u2078\u2078Sr\u207a frequency standard at 445 THz (674 nm) is completed and is in excellent agreement with previous measurements.Peer reviewed: YesNRC publication: Ye