Analysis of microcavity VCSEL lasing modes using a full-vectorweighted index method

摘要

Presents a semi-analytic full-vector method for calculating thenspatial profile, optical confinement factor resonant frequency,nabsorption loss, and mirror loss of lasing modes in cylindricallynsymmetric microcavity vertical-cavity surface-emitting lasers (VCSEL's).nIt can be shown that this method gives the best separable approximationnfor the electric and magnetic vector potentials. Our technique can modelnthe entire VCSEL structure and can treat complex media. We apply thenmethod to etched-post and oxide-apertured VCSEL's designed for 980-nmnemission and find a blueshift in cavity resonance as the cavity radiusnshrinks. We also find a minimum optical cavity radius below whichnradially bound lasing modes cannot be supported. This radius depends onnthe device geometry and lies between 0.5 and 1 Μm for the devicesnstudied. Once this model is augmented to include diffraction losses-thendominant loss mechanism for conventional small aperture lasers-it willnprovide a complete picture of lasing eigenmodes in microcavity VCSEL's