Effect of excited states on light-current characteristic of a quantum dot laser

摘要

Excited-state-mediated capture of carriers from the waveguide into the lasing ground-state in quantum dots (QDs) is studied. Such a two-step capture places a fundamental limitation on ground-state lasing — the output power saturates at high injection currents. The saturation power is controlled by the transition time between the excited- and ground-state in a QD. The longest, cut-off transition time exists, beyond which no ground-state lasing is possible.