| In response to the growing importance of vertical cavity surface emitting lasers (VCSELs), the semiconductor laser simulator Minilase has been extended to allow simulation of VCSEL devices. The fundamental physics of VCSELs are no different from the physics of other semiconductor lasers; however, the approximation of a closed boundary imposed on the optical modes by Minilase is no longer acceptable. Therefore, the extension of Minilase primarily required the development of a more sophisticated optical mode set for use with open VCSEL structures. The theory of this mode set is rigorously derived, including an unambiguous quasi-photon rate equation for use with Minilase. A specific implementation of this mode set, in the form of a Green's function based VCSEL mode solver (VMS), is presented. The VMS takes the electric susceptibility calculated from the electronic state of the quantum well as input, and provides the net modal gain and the optical recombination rates as outputs. The Green's function of the VCSEL optical cavity is obtained during the course of these calculations; therefore, this is used to obtain results for the highly modified spontaneous emission rates of strongly confined microcavity VCSEL structures. The VMS and the joint Minilase-VMS simulator have been extensively tested against other simulators and experimental data. Results from this testing are presented, as well as results and analysis which shed light on the ultimate performance possibilities and limitations of microcavity VCSEL devices. |
