Modeling of resistance characteristics of a continuously-graded distributed Bragg reflector in a 980-nm vertical-cavity surface-emitting laser

The resistance characteristics of a continuously-graded distributed Bragg reflector (DBR) in a 980-nm vertical-cavity surface-emitting laser (VCSEL) are modeled in detail. The junction resistances between the layers of both the p- and n-DBR mirrors are analysed by combining the thermionic emission model and the finite difference method. In the meantime, the intrinsic resistance of the DBR material system is calculated to make a comparison with the junction resistance. The minimal values of series resistances of the graded p- and n-type DBR mirrors and the lateral temperature-dependent resistance variation are calculated and discussed. The result indicates the potential to optimize the design of the DBR reflectors of the 980-nm VCSELs.