title: Fiber-laser frequency combs with subhertz relative linewidths.
abstract: We investigate the comb linewidths of self-referenced, fiber-laser-based frequency combs by measuring the heterodyne beat signal between two independent frequency combs that are phase locked to a common cw optical reference. We demonstrate that the optical comb lines can exhibit instrument-limited, subhertz relative linewidths across the comb spectra from 1200 to 1720 nm with a residual integrated optical phase jitter of approximately 1 rad in a 60 mHz to 500 kHz bandwidth. The projected relative pulse timing jitter is approximately 1 fs. This performance approaches that of Ti:sapphire frequency combs.
authors.affiliation: National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
authors.forename: W C
authors.initials: WC
authors.lastname: Swann
authors.forename: J J
authors.initials: JJ
authors.lastname: McFerran
authors.forename: I
authors.initials: I
authors.lastname: Coddington
authors.forename: N R
authors.initials: NR
authors.lastname: Newbury
authors.forename: I
authors.initials: I
authors.lastname: Hartl
authors.forename: M E
authors.initials: ME
authors.lastname: Fermann
authors.forename: P S
authors.initials: PS
authors.lastname: Westbrook
authors.forename: J W
authors.initials: JW
authors.lastname: Nicholson
authors.forename: K S
authors.initials: KS
authors.lastname: Feder
authors.forename: C
authors.initials: C
authors.lastname: Langrock
authors.forename: M M
authors.initials: MM
authors.lastname: Fejer