Design considerations for efficient planar-optical systems

Planar integrated free-space optics is well suited for various applications, e.g., in telecommunication, optical interconnects and security application. However the overall efficiency of purely diffractive systems is low, i.e., in the range of a few percent. We show that it is possible to raise the efficiency significantly by integration of refractive optical elements (prisms, wedges) for coupling into the substrate. In this case, the systems design is particularly challenging. We compare the impact of different coupling mechanisms on the optical designs of integrated 4f-imaging systems.