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 120 m 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 1.3-m ultrashort cavity devices such as
vertical-cavity surface-emitting lasers. Ground state laser action
was achieved for a 360-m-cavity length with as-cleaved facets.
The transparency current density per QD layer and internal
quantum efficiency were 13 A/cm2 and 67%, respectively.