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Self-assembled InAs quantum-dot lasers grown by molecular-beam epitaxy using an AlGaAsSb metamorphic buffer layer on a GaAs substrate are reported. The resulting quantum-dot ensemble has a density >3×1010/cm2 and a ground-state transition ranging from 1.46 to 1.63 μm. Pulsed, room-temperature operation generates lasing from the first excited state transition at wavelengths ranging from 1.27 to 1.34 μm. The minimum threshold current density (304 A/cm2) is achieved for a 7.7 mm cavity with cleaved, uncoated facets.

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We investigate the dynamical response of a quantum dot photonic integrated circuit formed with a combination of eleven passive and active gain cells operating when these cells are appropriately biased as a multi-section quantum dot passively mode-locked laser. When the absorber section is judiciously positioned in the laser cavity then fundamental frequency and harmonic mode-locking at repetition rates from 7.2GHz to 51GHz are recorded. These carefully engineered multi-section configurations that include a passive wave-guide section significantly lower the pulse width up to 34% from 9.7 to 6.4 picoseconds, as well increase by 49% the peak pulsed power from 150 to 224 mW, in comparison to conventional two-section configurations that are formed on the identical device under the same average power. In addition an ultra broad operation range with pulse width below ten picoseconds is obtained with the 3rd-harmonic mode-locking configuration. A record peak power of 234 mW for quantum dot mode-locked lasers operating over 40 GHz is reported for the first time.