title: Ultralow noise and supermode suppression in an actively mode-locked external-cavity semiconductor diode ring laser.
abstract: We report what is to our knowledge the lowest phase and amplitude noise characteristics achieved to date in a 10-GHz pulse train produced by the active harmonic mode locking of an external-cavity semiconductor diode laser. Supermode noise has also been suppressed below -140 dBc/Hz by use of a high-finesse fiber Fabry-Perot etalon as an intracavity filter. Novel noise sideband measurements that extend to the Nyquist offset frequency suggest a significant advantage in using harmonic (rather than fundamental) mode locking to produce ultralow-noise pulse trains, owing to the relationship between the noise roll-off frequency and the fundamental cavity frequency.
authors.forename: C M
authors.initials: CM
authors.lastname: Depriest
authors.forename: T
authors.initials: T
authors.lastname: Yilmaz
authors.forename: P J
authors.initials: PJ
authors.lastname: Delfyett
authors.forename: S
authors.initials: S
authors.lastname: Etemad
authors.forename: A
authors.initials: A
authors.lastname: Braun
authors.forename: J
authors.initials: J
authors.lastname: Abeles