Some aspects of designing an efficient nitride VCSEL resonator

The optical model of vertical-cavity surface-emitting lasers (VCSELs) based on the effective frequency method is applied to formulate some guidelines useful for designers of nitride VCSEL resonators. Various materials for res onator distributed Bragg reflectors mirrors are investigated, namely SiO2, TiO2, HfO2, MgO, Y2O3, ZrO2, GaN, AlN, and AlGaN. For pulse-operating nitri de VCSELs. both dielectric resonator mirrors (preferably SiO2/TiO2 stacks) are recommended, whereas in the case of continuous-wave operation, the bott om dielectric mirror should be replaced by a semiconducting one (e.g. CaN/A l0.15Ga0.85N stack) to enhance heat extraction. It is shown that the active region radius in the analysed lasers should not be less than 5 mum. The si mulation also revealed that the barrier width has a strong influence on the threshold gain. Some thermoelectrical aspects of design have also been add ressed.