Optical frequency comb for high-resolution and precision metrology

In this work we describe two optical frequency comb systems based on homemade high-repetition rate mode- locked femtosecond Ti:sapphire lasers. One of them uses a laser that has the spectrum broadened with a microstructure fiber to cover a whole optical octave. Its repetition rate can be easily adjusted form 750 MHz to 1 GHz. The other system is based in a ultra-broadband femtosecond high repetition rate Ti:sapphire laser whose spectrum covers a range from 585 nm to 1200 nm (at 20 dB below the maximum) without the use of the microstructure fibers. We have increased the repetition rate from 1 GHz to 2.12 GHz without observing any significant change in the width of the spectrum. The repetition rate of both lasers has been phase- locked to stable microwave oscillators, and could also be frequency tuned in a range of 30 kHz with respect to the reference oscillator. We are going to use these systems in a direct optical frequency measurement technique and in an optical atomic clock based on the Calcium intercombination transition at 457 THz.