Dependence of threshold current density on the stacked quantum dot layers

Lasers based on InGaAs/(Ga,Al)As stacked QDs layers are fabricated. The performance of the quantum dots laser is dependent on the detailed design of the active region. The threshold current density is greatly decreased by the use of multiple-layer quantum dots, coupled dots layers, or barriers with wide band gap. An average threshold current density of about 20A/cm2 is achieved for the laser with the width of 15micron.