Numerical solution of lateral current spreading and diffusion in near-threshold DH twin-stripe lasers

A numerical solution is presented to the problem of lateral current spreading in double heterostructure twin-stripe lasers when lateral diffusion of carriers and bimolecular recombination effects are present. The current components flowing into both the p-type confining layer and the active layer are solved simultaneously, subject to the boundary conditions imposed at the heterojunction. This yields the two-dimensional potential and the current density distributions in the p-type confining layer and the lateral carder density distribution in the active region. Diffusion and bimolecular radiative recombination effects are included in the solution of the current distribution in the active layer. The lateral current and carrier density distributions along the active layer are presented for single- and twin-stripe devices for a variety of electrode injection currents. The paper highlights the influence of device geometry and diffusion on the carrier distributions found beneath the stripes of twin-stripe lasers.