Thermodynamic balance in quantum dotlasers

Abstract

The spontaneous emission and optical gain spectra from an InGaAsquantum dot laser have been independently measured under thesame operating conditions. Using these spectra a combinedprobability-distribution function describing the electronoccupancy in the conduction and valence bands has beenexperimentally determined. Comparison of this function withtheoretical curves based on Fermi-Dirac statistics shows thatfor temperatures down to 100 K the carrier occupancy statisticsare accurately described by thermal distributions. Measurementsat 70 K show a breakdown of thermodynamic equilibrium indicatedby non-thermal carrier distributions.