Active and passive components of 3D integrated optics
The potential of 3D integrated optics based on different technological schemes is investigated. Theoretical and experimental results for waveguide geometries with stacked waveguide layers and with waveguide circuits prepared on topological structures are reported as well. Within waveguide geometries including individual guides in a sequence of stacked layers directional coupler arrays allow for short length passive signal distribution, and various schemes of single and multipath switching can be identified. Cost effective preparation technologies as spin coating of polymer and PECVD of SiON layers and their patterning by UV- exposure or RIE, respectively, have been prove to fulfill the critical tolerance requirements of a simultaneous directional coupling in two transversal directions. To realize waveguides with smooth height variation gray scale lithography was used to produce topological surfaces. Upon those surfaces waveguide paths and devices can be defined subsequently, which are useful e.g. for non-planar to planar fan out structures or interferometer configurations for sensing applications. The topological surfaces can be replicated very efficiently by reaction molding, a technology widely used for micro-optical structures, too.