QUASI-EXACT OPTICAL ANALYSIS OF OXIDE-APERTURED MICROCAVITY VCSELS USING VECTOR FINITE-ELEMENTS

We report a new full vector finite element model for analyzing the opt ical properties of azimuthally symmetric oxide-apertured vertical-cavi ty surface-emitting lasers (VCSEL's), Our model allows for quasi-exact calculation of the lasing mode blueshift, threshold gain, and field p rofile. Through a detailed analysis of a sample VCSEL, we ascertain th e physical effects which determine diffractive or parasitic mode loss. They are: 1) the background density of parasitic modes and 2) the cou pling strength between the lasing mode and the parasitic mode continuu m. The coupling strength is in turn determined by the relative alignme nt between the lasing and parasitic mode propagation vectors and the l asing mode penetration into the oxide region. This analysis improves o ur understanding of the optical physics of apertured VCSEL's and shoul d enable the next leap down in lasing threshold.