Investigation of passive mode-locking and self mode-locking in two-section monolithic QW and QD lasers

In this study, we conduct a comparative analysis of an InAs/InP quantum dot diode laser and an InGaAsP/InP quantum well laser. Both lasers are monolithic, 840 μm long devices. They have a two-part buried heterostructure with 10%/90% reflection coated facets and emit at 1550 nm (quantum dot laser) respectively 1570 nm (quantum well laser). In passive mode-locking operational mode, the larger section of both devices is continuously pumped with forward current, while the second, smaller section (50 μm) is operated with reverse absorber voltage. In self mode-locking operation both sections of the laser are connected and pumped with forward current. Femtosecond pulses have been detected in both operational modes.