title: Optical linewidth of a passively mode-locked semiconductor laser.
abstract: We measured the optical linewidths of a passively mode-locked quantum dot laser and show that, in agreement with theoretical predictions, the modal linewidth exhibits a parabolic dependence with the mode optical frequency. The minimum linewidth follows a Schawlow-Townes behavior with a rebroadening at high power. In addition, the slope of the parabola is proportional to the RF linewidth of the laser and can therefore provide a direct measurement of the timing jitter. Such a measurement could be easily applied to mode-locked semiconductor lasers with a fast repetition rate where the RF linewidth cannot be directly measured.
authors.affiliation: Tyndall National Institute, Lee Maltings, Cork, Ireland. tatiana.gabruseva@gmail.com
authors.forename: T
authors.initials: T
authors.lastname: Habruseva
authors.forename: S
authors.initials: S
authors.lastname: O'Donoghue
authors.forename: N
authors.initials: N
authors.lastname: Rebrova
authors.forename: F
authors.initials: F
authors.lastname: Kéfélian
authors.forename: S P
authors.initials: SP
authors.lastname: Hegarty
authors.forename: G
authors.initials: G
authors.lastname: Huyet