Design limitations for InGaN/AlGaN/GaN lasers imposed by resonant mode coupling

Summary form only given. Present-day InGaN-AlGaN-GaN semiconductor lasers typically contain a multiple optical waveguide structure, with refractive indices of several layers (GaN buffer-substrate, active region, cap layer) higher than those of cladding layers. This leads to complex behavior of optical modes. Here, we show that resonant effects in nitride lasers result from coupling between nearly-degenerate normal modes of the entire laser structure, similarly to the case of InGaAs-based lasers analyzed previously. We also demonstrate the strong role of the parasitic waveguide thicknesses, in addition to previously investigated parameters.