Lasing characteristics of coupled InGaAs/GaAs multi-layers quantum dots laser

Coupled multi-layers InGaAs/GaAs quantum dots materials were grown by MBE. The lasers were fabricated in the geometry of oxide stripes. The temperature dependence of threshold current density is measured for the lasers with different cavity lengths. The average threshold current density is as low as 48 A/cm2, a record as we know. The laser with long cavity exhibits lasing at ground QDs state while lasing at excited quantum dot state or wetting layer state dominates the transition for lasers with shorter cavity