Significantly improved performances of 1.3 μm InAs/GaAs QD laser by spatially separated dual-doping

We report on significantly enhanced performances of 1.3 μm InAs/GaAs quantum dot (QD) lasers by spatially separated dual-doping, including p-type modulation doping in barrier layers and n-type direct doping in QDs simultaneously. The QD lasers are a ridge waveguide of 6 × 1000 μm2 with uncoated facets, whose active region consists of eight stacked InAs QD layers. Compared with the conventional single p-type modulation doped (p-doped) QD laser, the dually doped QD laser achieves a reduced threshold current from 51.07 to 43 mA, an increased single-sided slope efficiency from 0.18 to 0.25 W/A at 25 °C, and an increased characteristic temperature T0 from 654 to 7917 K between 15 and 85 °C. Furthermore, the continuous wave output power of the dually doped QD laser exceeds 20 mW without any attenuation at 85 °C, whereas that of the p-doped one appears to be saturated at 14.08 mW. The results presented here have important implications for realizing high-performance QD lasers emitting at 1.3 μm to various applications.