A 350MHz Ti:sapphire laser comb based on monolithic scheme and absolute frequency measurement of 729nm laser

Abstract

We realized a novel frequency comb based on femtosecond Ti:sapphire laser with 350 MHz repetition rate and monolithic scheme for carrier-envelope-offset frequency generation. Long-term stabilization of more than 9 hours was demonstrated by simultaneously locking repetition rate (f(rep)) and carrier-envelope-offset frequency (f(ceo)) to an atomic clock. The Allan deviations of f(ceo) and f(rep) are 2.3 x 10(-13) and 1.5 x 10(-15) at 100 s averaging time, respectively, and the reproducibility of f(ceo) with high accurate performance is also verified by comparison of the locking results recorded in 3 different days. By avoiding the extra noise induced by photonic crystal fiber, we obtained the accumulated phase error increase from in-loop to out-of-loop as small as 12 mrad [1 Hz, 100 kHz]. Furthermore, the absolute optical frequency of a stabilized 729 nm Ti:sapphire laser which is referenced to a ultra-low expansion (ULE) cavity is measured by the comb and determined to be 411041985391583+/-10 Hz.