Hybrid mode-locking in a 40 GHz monolithic quantum dot laser

This work studies experimentally and theoretically a monolithic two-section hybrid mode-locked quantum dot laser with periodically modulated reverse bias applied to the saturable absorber section. Experimental investigations have been carried out with a 40 GHz QD-MLL (quantum dot mode-locked lasers) module, comprising a standard single mode fiber pigtail and a microwave port. It is based on a two-section QD laser diode having a 4 mum wide ridge waveguide structure. A theoretical model of a quantum dot laser is based on a set of delay differential equations governing the time evolution of the electric field envelope, carrier densities in the wetting layers and occupation probabilities of the quantum dots in the gain absorber sections.