title: Elimination of pump-induced frequency jitter on fiber-laser frequency combs.
abstract: Optical frequency combs generated by femtosecond fiber lasers typically exhibit significant frequency noise that causes broad optical linewidths, particularly in the comb wings and in the carrier-envelope offset frequency (f(ceo)) signal. We show these broad linewidths are mainly a result of white amplitude noise on the pump diode laser that leads to a breathing-like motion of the comb about a central fixed frequency. By a combination of passive noise reduction and active feedback using phase-lead compensation, this noise source is eliminated, thereby reducing the f(ceo) linewidth from 250 kHz to <1 Hz. The in-loop carrier-envelope offset phase jitter, integrated to 100 kHz, is 1.3 rad.
authors.affiliation: National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: McFerran
authors.forename: W C
authors.initials: WC
authors.lastname: Swann
authors.forename: B R
authors.initials: BR
authors.lastname: Washburn
authors.forename: N R
authors.initials: NR
authors.lastname: Newbury