Current crowding in oxide-confined intracavity-contacted VCSELs

An important problem for intracavity-contacted oxide-confined Vertical-Cavity Surface-Emitting Lasers (ICOC-VCSELs) is current crowding at the inner edges of the oxide current constrictions, which introduces extra losses and leads to excitation of unwanted higher-order transverse modes. We have proposed novel ’asymmetric’ ICOC-VCSELs, where the contact metallisations are restricted to opposite mesa sides, for more homogeneous current injection and polarisation control. Here, results of simple 2D drift-diffusion calculations are presented for symmetric and asymmetric ICOC-VCSELs. Current crowding in our ’asymmetric’ devices is reduced, but depends on the design of the layer structure.