Multiscale and Multiphysics Solvers for AlGaAs TJ-VCSEL

Among possible strategies to improve the performance of near infrared AlGaAs/GaAs vertical-cavity surface-emitting lasers (VCSELs) for short-reach interconnects, current injection schemes based on tunnel junctions (TJs) may be an enabling technology to meet the high temperature requirements of data-center applications. To assess the merits of TJs in this context, we perform a comparative simulation-based study of a commercial pin VCSEL and a modified structure where holes are injected into the active region through a TJ. Band-to-band tunneling probabilities are computed within a multiband nonequilibrium Green's function (NEGF) approach. The resulting generation rates are included in a quantum-corrected drift-diffusion model for carrier transport. The optical modes of the cavity are found with an electromagnetic solver, and self-heating effects are studied with a thermal model. The comparative multiphysical 1D and 3D simulations of pin and TJ-VCSELs predict that the voltage penalty introduced by the reverse-biased TJ is compensated by the higher output optical power.