Quantum dot vertical cavity lasers

We focus on improving the QD VCSEL fabrication process and extending the emission wavelength up to and beyond 1.55 /spl mu/m. The wavelength extension is accomplished by varying the physical size and composition of sheets of InAs-InGaAs dots grown directly on GaAs substrates. We also investigate tunable QD VCSELs for application in dense wavelength division multiplexing optical communication systems. We study important design and fabrication issues associated with the development of prototype, long-wavelength tunable QD VCSELs. This work includes studies of optically efficient InAsInGaAs quantum dot gain layers within the microcavity active region, where the size of the QDs is either highly uniform or variable.