Comparison of modelling techniques for multimode fibers and its application to VCSEL source coupling

Ray tracing and split-step method are the most efficient techniques to model multi-mode fiber. In this work, we also propose a geometrical optics based approach, which is beyond ray tracing. This approach, which is mathematically based on Runge-Kutta methods, handles not only ray information but light field information, e.g. amplitude and polarization. Then we discuss and compare the different techniques by the example of coupling of a VCSEL source into a multi-mode fiber.