3D-Opto-MID for Asymmetric Optical Bus Couplers

The development of easy-to-use optical bus-systems without the need for waveguide interruption is one important step to establish optical interconnects in short- to midrange networks. The challenge from the packaging side of view is the three-dimensional integration of optical parts and waveguides to a novel kind of package, called 3D-Opto-MID. In this article, we present an approach for stereolithographic printed, three-dimensional polymer structures on ceramic thick-film substrates. Thus, we are able to combine the design freedom of 3D printing with the excellent RF- and heat-management properties of the thick-film technology, especially important for electro-optical (e/o) converters. On the three-dimensional structures, the waveguides for the bus-coupler are applied, while the ceramic holds the electro optical converters. Furthermore, the 3D printing allows for easily manufactured alignment- and fixing structures for the coupler with a high accuracy. The results section shows the analysis of the adhesion behavior of the printed polymer on the ceramic, as well as the obtainable tolerances with the printed alignment structures. The average accuracy of the alignment was measured with 31.1μm, which is sufficient for the used 200 μm multimode waveguides. Furthermore, we demonstrate the functionality of the optical path of the module assembly, as well as the coupling to a bus waveguide, which proves the success of the 3D-Opto-MID integration.