High modal gain 1300-nm In(Ga)As/GaAs quantum dot lasers

A semiconductor laser containing seven InAs-In-GaAs stacked quantum-dot (QD) layers was grown by molecular beam epitaxy. Shallow mesa ridge-waveguide lasers with stripe width of 120micron were fabricated and tested. A high modal gain of 41 cm-1 was obtained at room temperature corresponding to a modal gain of 6 cm-1 per QD layer, which is very promising to enable the realization of 1.3micron ultrashort cavity devices such as vertical-cavity surface-emitting lasers. Ground state laser action was achieved for a 360micron-cavity length with as-cleaved facets. The transparency current density per QD layer and internal quantum efficiency were 13 A/cm2 and 67%, respectively.