Inhomogeneous gain effects in quantum dot lasers

A comparison of optical and electrical derivative spectroscopy on a dual-state lasing InAs/GaAs quantum dot bilayer device is presented. The junction voltage cannot be described by a quasi-Fermi level separation and only partial clamping above the laser threshold was observed, demonstrating inhomogeneous gain. There is also competition between transverse optical modes which must be taken into account for a full understanding of dual-state lasing