LAUSR

Abstract Femtosecond optical frequency combs play important roles in various scientific and technical fields. For example, they can be used for frequency measurements, distance measurements, and in precision spectroscopy. The repetition rate of this type of comb can be tuned in a wide range by controlling the cavity length. This has here been done by using a combination of a motorized stage and a piezoelectric transducer (PZT). A very stable Er-doped fiber femtosecond laser, with a repetition rate of 200 MHz and a pulse duration of 68 fs, was then developed. In addition, a tunable repetition rate adjustment of 1.664 MHz was successively achieved. The fluctuation in the repetition rate was less than 100 Hz in 120 h in the free-running state. Moreover, the average output power was 105.05 mW, with a standard deviation of 0.09 mW for a duration of 110 h The repetition rate and carrier-envelope offset frequency were continuously phase-locked to a microwave reference for more than 30 days with a standard deviation of 0.327 mHz and 0.569 mHz, respectively.