title: Improved signal-to-noise ratio of 10 GHz microwave signals generated with a mode-filtered femtosecond laser frequency comb.
abstract: We use a Fabry-Perot cavity to optically filter the output of a Ti:sapphire frequency comb to integer multiples of the original 1 GHz mode spacing. This effectively increases the pulse repetition rate, which is useful for several applications. In the case of low-noise microwave signal generation, such filtering leads to improved linearity of the high-speed photodiodes that detect the mode-locked laser pulse train. The result is significantly improved signal-to-noise ratio at the 10 GHz harmonic with the potential for a shot-noise limited single sideband phase noise floor near -168 dBc/Hz.
authors.affiliation: Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, USA. sdiddams@boulder.nist.gov
authors.forename: S A
authors.initials: SA
authors.lastname: Diddams
authors.forename: M
authors.initials: M
authors.lastname: Kirchner
authors.forename: T
authors.initials: T
authors.lastname: Fortier
authors.forename: D
authors.initials: D
authors.lastname: Braje
authors.forename: A M
authors.initials: AM
authors.lastname: Weiner
authors.forename: L
authors.initials: L
authors.lastname: Hollberg