Design of quantum structure stripe lasers for low threshold current

In the case of quantum structure lasers, including quantum well, quantum wi re and quantum box lasers, a simple method is presented to obtain optimal s tructure of the active region for a low threshold condition. A logarithmic description is used to describe the relationship between the material gain and the injected carrier density. Taking an InGaAs(P)InP quantum-well laser and an InAs/GaAs self-assembled quantum box laser for example, the optimal condition to obtain the lowest threshold current are provided, including t he number of quantum wells, the area density of quantum boxes, and the cavi ty length. The results show that a multi-stacked active region is very nece ssary to obtain a low threshold current for self-assembled quantum dot lase rs.