Spontaneous emission study on 1.3μm InAs/InGaAs/GaAs quantum dot lasers

摘要

True spontaneous emission (TSE) measurements on InAs/InGaAs/GaAs quantum dot (QD) lasers have been performed as a function of injection current and cavity length. For each laser, TSE from both the ground state (GS) transition and the excited state (ES) transition has been analyzed. It is found that Auger processes are the major nonradiative recombination (NR) processes for both the GS and ES transitions. In particular, for the first time, the existence of Auger like NR features in ES transitions has been experimentally demonstrated. In addition, obvious competition for carriers between the ES transition and the GS transition has been observed in TSE analysis. Furthermore, the QD laser's cavity length has a strong effect on the NR process in GS transitions, due to GS gain saturation. Therefore, when analyzing the NR processes in operating QD lasers, gain saturation due to cavity length limits should be properly considered.