Models for the coupling of light into multimode waveguides

For the simulation of light transmission over optical interconnects an appropriate modeling of the coupling process is needed. Comprehensive methods like the mode matching method can offer accurate results as long as a very high number of modes on both sides of the coupling interface is available. In this paper, some simpler numerical methods are assessed and compared to the results of the mode matching method applied to a 2D coupling problem. It turns out that these methods can be used well under usual operating conditions for highly multimodal waveguides, but the errors increase with the deviation from the non-ideal coupling geometry.