Optimization of a New GaN-Based Blue Laser Diode with a Quadruple Asymmetric Waveguide for High Efficiency Performance

In this work, for the first time, the improved lasing performance of a blue GaNbased laser diode is demonstrated by the introduction and vertical optimization of a new quadruple asymmetric waveguide structure. In the new proposed waveguide structure, in the first step, p-waveguide and electron blocking layers have been omitted. Then a triple asymmetry was considered for the design of an AlGaNp-cladding layer inside the waveguide structure. The performances of the conventional and proposed laser structures were theoretically studied using the photonic integrated circuit simulator in 3D simulation software. The 3deminsional simulations of carrier transport, optical wave- guiding and self-heating were combined self-consistently in the software. A good agreement was achieved between simulations and experiments by careful choice of different material parameters in the physical models. The effects of the AlGaN p-cladding layer properties on the performance of the new quadruple asymmetric waveguide GaN-based laser were theoretically studied. Threshold current, output power, and operation voltage were compared for different composition of Al, doping, and thickness of the AlGaN p-cladding layer. According to the simulation results, the optimized values of Al composition, doping, and thickness of the AlGaN p-cladding layer obtained for high-power performance.