title: Femtosecond pulses from a modelocked integrated external-cavity surface emitting laser (MIXSEL).
abstract: Novel surface-emitting optically pumped semiconductor lasers have demonstrated >1 W modelocked and >100 W continuous wave (cw) average output power. The modelocked integrated external-cavity surface emitting laser (MIXSEL) combines the gain of vertical-external-cavity surface-emitting lasers (VECSELs) with the saturable absorber of a semiconductor saturable absorber mirror (SESAM) in one single semiconductor structure. This unique concept allows for stable and self-starting passive modelocking in a simple straight cavity. With quantum-dot based absorbers, record-high average output power was demonstrated previously, however the pulse duration was limited to 17 ps so far. Here, we present the first femtosecond MIXSEL emitting pulses with a duration as short as 620 fs at 4.8 GHz repetition rate and 101 mW average output power. The novel MIXSEL structure relies on a single low temperature grown quantum-well saturable absorber with a low saturation fluence and fast recovery dynamics. A detailed characterization of the key modelocking parameters of the absorber and the challenges for absorber integration into the MIXSEL structure are discussed.
authors.forename: Mario
authors.initials: M
authors.lastname: Mangold
authors.forename: Valentin J
authors.initials: VJ
authors.lastname: Wittwer
authors.forename: Christian A
authors.initials: CA
authors.lastname: Zaugg
authors.forename: Sandro M
authors.initials: SM
authors.lastname: Link
authors.forename: Matthias
authors.initials: M
authors.lastname: Golling
authors.forename: Bauke W
authors.initials: BW
authors.lastname: Tilma
authors.forename: Ursula
authors.initials: U
authors.lastname: Keller