High modal gain 1.5 μm InP based quantum dot lasers: dependence of static properties on the active layer design

Based on a novel quantum dot (QD) growth technique, high density dot-like QDs were grown on (100)InAlGaAs/InP surfaces, which resulted in a strongly improved modal gain in 1.55 mu m QD lasers. The influence of the number of QD layers on static properties, e.g., modal gain, threshold current density and spectral properties, are presented and discussed. For a large number of QD layers, e.g., 6 QD layers, a high modal gain of > 70cm(-1) could be obtained. By reducing the number of QD layers, i.e., lowering the modal gain, the wavelength shift with temperature can be reduced to < 0.2 nm/K. Systematic dependence of laser properties on structural parameters is observed.