Optimal Design of Combined Distributed-Feedback/Fabry-Perot Structures for Vertical Cavity Surface Emitting Semiconductor Lasers

In this paper, we investigate the optimal design of combined distributedfeedback/Fabry-Perot (DFB/FP) structures for vertical cavity surface-emitting semiconductor lasers (VCSELs) using a self-consistent model based on coupled-wave equations and on the dependence of gain coupling on the threshold gain. Numerical results, carried out for the GaInAsP/InP material system, confirmed that a much lower threshold current density can be achieved in VCSELs with optimally designed DFB/FP structures. The results thus imply that a potential exists for realizing lower threshold VCSELs with technologically feasible mirror reflectivities and cavity lengths.