<title>FD-BPM modeling of vertical-cavity surface-emitting lasers</title>

Abstract

A self-consistent 3D model using the finite difference beam propagation method in cylindrical coordinates is presented to assess the performance of vertical cavity surface emitting lasers. It calculates the optical field pattern, output power, carrier distribution in the active layer and secondary mode excess loss. Optical diffraction and scattering are automatically included in the propagation, as well as carrier diffusion and spatial hole burning. Calculations using this model clearly show the advantage of current confinement by oxidation over proton implantation. The threshold current in oxide confined devices is predicted to reach a minimum at aperture diameters around typically 1.5 to 2.0 micrometers with a (lambda) /4 oxidized AlAs layer, compared to 12 micrometers in proton-implanted ones. The oxide thickness can still be optimized to minimize scattering losses. Tapered oxide profiles can also be considered. For current aperture diameters below 4 micrometers , single-mode behavior around threshold can be expected. Above threshold, the secondary mode rejection ratio is largely influenced by carrier diffusion which partly washes out the carrier inhomogeneity caused by spatial hole burning.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.