Understanding Ground-State Quenching in Quantum-Dot Lasers

Quantum-dot lasers can exhibit simultaneous ground- and excited-state lasing. With increasing pump current, a quenching of the ground-state lasing intensity is sometimes observed. The causes for this are investigated, and its dependence on temperature, gain, and electron-hole asymmetry is studied via an analytical approach. A numerical model based on the semiconductor Bloch equations with a set of rate equations for electrons and holes is used for validation. We also investigate the influence of doping and different cavity lengths on the two-state lasing dynamics. We find that ground-state quenching is more common in p-doped, short cavity devices with low gain.