Highly stacked quantum-dot laser fabricated using a strain compensation technique

We used a strain compensation technique to fabricate highly stacked InAs quantum-dot (QD) structures on InP(311)B substrates. We stacked 60 layers of InAs QDs without degrading the crystal quality and produced a structure with a total QD density of 4.73 × 10 12 ∕ cm 2 . We then fabricated a broad area laser diode with a 30-layer stack of InAs QDs using conventional photolithography. The laser diode showed ground state lasing at 1.58 μ m with a threshold current of 162 mA . The achievement of ground state lasing is due to the increase in QD density, which is a result of using the strain compensation technique.