Numerical estimates of lateral current spreading and carrier diffusion in multiple‐stripe‐geometry AlGaAs lasers, both with and without zinc diffusion, are presented. This is the first analysis of the effect of zinc diffusion on the injected current and carrier density profiles. Results show that with a higher zinc diffusion depth, these lasers have significantly reduced current spreading, lower operating currents, and improved carrier density profiles. However, the higher zinc diffusion depths may lead to some undesirable dips in the injected current density profiles.