VCSELs are semiconductor laser diodes which emit the light perpendicular to the chip surface. They have several advantages over the conventional edge-emitting lasers which makes them highly attractive for applications in optoelectronics. While edge-emitters cannot be tested until the end of the production process, VCSELs can be tested on the wafer. Further large two-dimensional arrays of devices can be built on a single wafer. This reduces the cost of the fabrication. The lower divergence angle of the output beam allows high coupling efficiency with optical fibers. Additionally they have lower power consumption than edge-emitting lasers. In this cooperative project between WIAS and ZIB within the SFB 787 semiclassical models of 3D-structured VCSELs are developed and analyzed, converted into numerical algorithms, and basing on this simulations are made. Our aim is the efficient simulation of VCSELs with a complex 3D-Structure in order to obtain a deep understanding of the several physical effects.