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 resonator distributed Bragg reflectors mirrors are investigated, namely SiO(2), TiO(2), HfO(2), MgO, Y(2)O(3), ZrO(2), GaN, AlN, and AlGaN. For pulse-operating nitride VCSELs. both dielectric resonator mirrors (preferably SiO(2)/TiO(2) stacks) are recommended, whereas in the case of continuous-wave operation, the bottom dielectric mirror should be replaced by a semiconducting one (e.g. CaN/Al(0.15)Ga(0.85)N 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 simulation also revealed that the barrier width has a strong influence on the threshold gain. Some thermoelectrical aspects of design have also been addressed.