Compact representations of mode overlap for circuit-level VCSEL models

The compact representations for mode overlap presented simplify the implementation, simulation, and extraction of circuit-level VCSEL models by eliminating the need for numerically evaluating these models overlap integrals whenever the degree of overlap between transverse mode and carrier profiles changes. By adopting either analytical fits for the integrals, or linearly-interpolated tables of pre-calculated integral values, it becomes possible for the user of these models to interactively alter the overlap without impacting the simulation time.