1.3 µm InAs/GaAs Quantum‐Dot Lasers with p‐Type, n‐Type, and Co‐Doped Modulation

To further enhance the performance and understand the mechanism of InAs quantum dot (QD) laser under high temperature, both theoretically and experimentally it is investigated, the effects of the technique of the combination of direct n‐type doping and modulation p‐type doping, namely co‐doping, in the active region for a wide temperature range over 165 °C. Through the comparison of co‐doped, modulation p‐type doped, direct n‐type doped, and undoped QD lasers, it reveals that the co‐doping technique provides a significantly reduced threshold current density across the whole temperature range and robust high‐temperature operation. Furthermore, it is also observed that the effectiveness of co‐doping in suppressing round‐state quenching is comparable to that of p‐doping. The improvements in the doping strategies are also revealed through the rate equation simulation of the lasers. This work reveals the different doping techniques that are applied to the quantum dot laser active region theoretically and experimentally. Remarkably, high‐temperature operation has been demonstrated with the introduction of co‐doping technique.