The effects of lateral current spreading, carrier out-diffusion, and optical mode losses on the threshold current density of GaAs-AlχGa1−χAs stripe-geometry DH lasers

Abstract

A calculation of the effect of stripe width on the threshold current density of stripe‐geometry GaAs‐Al_χGa_1−χAs DH lasers is given. This calculation includes the effects of lateral current spreading, carrier out‐diffusion from the stripe, and optical mode losses. The relative importance of each of these effects is determined and threshold calculations are done for a variety of typical laser parameters such as Al content of the cladding layers, sheet resistance of the layers above the active layer, active layer thickness, and carrier diffusion length of the minority carriers in the active layer. Calculated curves for the variation of the threshold current density with stripe width and active layer thickness are compared to experimental data for a variety of types of stripe‐geometry lasers. The agreement obtained between theory and experiment is excellent in all cases.