Threshold current density and emitting wavelength evolution with stack number in InAs quantum dash lasers at 1.55 μm

The authors demonstrate the achievement of InAs quantum dash lasers grown by molecular beam epitaxy (MBE) on InP (100) substrate. The lasers exhibit lasing wavelength at 1.55 mum by multiple stacked dash layers from two to five, with ground state lasing at room temperature. The threshold current density reaches a minimum value of 683 A/cm² from double quantum dash structure, resulting from the trade-off between the low number of carrier requirement in the InAs active region and the reduction of carrier concentration in the optical waveguide.