High-Power Sub-300-Femtosecond Quantum Dot Semiconductor Disk Lasers

Abstract

Self-assembled quantum dots (QDs) as active media for ultrafast semiconductor disk laser offer large gain bandwidths, fast gain dynamics, and high temperature stability. We report on the shortest pulses and the highest pulse peak power from an optically pumped vertical external cavity surface emitting laser (VECSEL) based on QDs and optimized for passive modelocking at 1035 nm using a semiconductor saturable absorber mirror. We demonstrate 216-fs pulses with an average output power of 269 mW at a pulse repetition rate of 2.77 GHz and 396 W peak power. At a lower pulse repetition rate of 1.67 GHz, we achieve 193-fs pulses with 112 mW of average output power. We remark a higher optical-to-optical pump efficiency compared to our previous QW VECSELs in the sub-300-fs regime. This is further confirmed by a comparative analysis of the saturation recovery which reveals longer carrier lifetimes for the QD compared to QW VECSELs.