Cavity optimization of 1.3um InAs/InGaAs quantum dot passively mode-locked lasers

Performance improving for monolithic two-section passively mode-locked (ML) quantum dot lasers has been systematically investigated using the Finite-Difference Traveling-Wave numerical model. Two approaches have been considered. For the first case, we changed simultaneously the length of the saturable absorber and the output facet reflectivity. We demonstrate that, by properly choosing these two parameters, a reduction of the pulse width from 3.4 ps to 1.1 ps and an increase the peak power 1 W to 1.6 W were obtained. For another case, we exchanged the optical power reflectivities at two end facets. We found that this approach can be used to further improve the ML stability for devices considered in the first approach where trailing edge instability is the main restriction.