Simulation of coupling efficiency for surface integration of optical waveguides

Polymer optical waveguides are increasingly being used for short distance communication links. They are especially developed and applied in areas, where the conventional use of electrical solutions for signal transmission is limited, due to data transfer rates and electromagnetic compatibility. The prerequisite for an operational optical communication link is the end-facets preparation of the light waveguide and coupling to light beam sender and receiver. These steps are achieved sequentially and independently from each other. We are developing a single system for these steps to achieve an automated surface integration and assembly of polymer optical waveguides onto different substrate surfaces. Therefore, it is essential to pinpoint the necessary position accuracy to achieve an efficient optical coupling. We simulated the coupling efficiency using variations of sender alignment to surface integrated optical waveguides. Thereby, an important aspect was the differentiation between butt coupling and coupling using additional optical lenses. Based on the results, we can make a statement about maximal allowed tolerances. Consequently, it is possible to deduce the actuator design and the kinematics needed in the approached system. Various parameters such as cross-section geometry of the optical waveguide, light divergence of the beam sender, degrees of freedom and optical surface roughness, were considered in the simulations. This article presents the method used and discusses the delivered results.