Wave-optical simulation of a complex micro-optical system including tilted optical elements

In some applications the efficient wave optical propagation of an electromagnetic field from a plane to a tilted plane is required. As an example the so called "optical bridge" system is used, which was one of the benchmark systems for simulations in the European Network of Excellence on Micro-Optics (NEMO). The optical bridge system connects each channel of an emitter with several channels of the receiver. For this purpose first of all a microlens array collimates the light of a VCSEL array. Then, the light propagates through a right-angle prism made of PMMA to a second microlens array in front of the receiver array. On one of the lateral surfaces of the prism a diffractive beam splitter element is positioned, which means that it is tilted by 45° relative to the local optical axis to have total internal reflection in the prism. The beam splitter is a cross grating where the fine structure of one period is designed in such a way that the diffraction efficiency in the central 3x3 diffraction orders is nearly equal and nearly zero in all other orders. We will present our simulation result and a comparison with the other benchmark results.