Improvement of modal gain of InAs/InP quantum-dash lasers

The optimization of modal gain in InAs/InP quantum-dash based lasers is reported in detail. Using either p-doped 6 dash-in-a-well or undoped 15 dash-in-a-well structures, we demonstrate modal gain up to 60cm
^-1
. This improvement induces an increase of differential gain and therefore leads to high resonance frequency (>;10GHz) and low linewidth enhancement factor (<;2.5). It opens the way to a further optimization of both quantum-dash stacking and p-doping as well as a proper combination of the two approaches.