A comprehensive model for the modal dynamics of vertical-cavity surface-emitting lasers

We present a quasi-3-D dynamic model of vertical-cavity surface-emitting lasers (VCSELs). The interdependent processes of carrier transport, heat generation and dissipation, and optical fields are solved self-consistently for each point in time and space. An effective index model is adopted for the evaluation of the optical fields in the complex layer structure. The inclusion of a temperature- and carrier-density-dependent refractive index, and its time dependence, allows us to study the evolution of the transverse optical field distributions under dynamic conditions. The model is applied to a typical index-guided structure with a 7-mum oxide aperture. A direct comparison is made using "cold" cavity modes, which is a normal technique when modeling the dynamics of VCSELs. Significant discrepancies are demonstrated both at small- and large-signal modulation, which indicates the need of a more sophisticated model for accurately predicting and understanding the geometry-dependent modal evolution.