Phase-locking the 3 GHz repetition rate of an ultracompact femtosecond modelocked laser

Summary form only given. Accurate measurements of optical frequencies are important for the realization of optical clocks as well as for the improved determination of certain fundamental constants. A newly-developed technique pioneered by Hansch et al. (1999) accurately controls the broad optical-frequency comb from a femtosecond laser to span the very large gaps associated with measuring optical frequencies; gaps as large as 100 THz have recently been measured. By stabilizing both the repetition rate and cavity phase of these femtosecond lasers, an accurate ultrawide frequency grid can replace the many bisection stages necessary for optical-to-microwave conversion. This approach has the potential to greatly simplify the measurements of absolute optical frequencies. We explore the use of an ultracompact femtosecond laser with a high repetition rate for generating a stable frequency comb.