Photonic-integrated circuits with non-planar topologies realized by 3D-printed waveguide overpasses

Aleksandar Nesic, Matthias Blaicher, Tobias Hoose, Andreas Hofmann, Matthias Lauermann, Yasar Kutuvantavida, Martin Nöllenburg, Sebastian Randel, Wolfgang Freude, Christian Koos
2019 Optics Express  
Complex photonic-integrated circuits (PIC) may have strongly non-planar topologies that require waveguide crossings (WGX) when realized in single-layer integration platforms. The number of WGX increases rapidly with the complexity of the circuit, in particular when it comes to highly interconnected optical switch topologies. Here, we present a concept for WGX-free PIC that relies on 3D-printed freeform waveguide overpasses (WOP). We experimentally demonstrate the viability of our approach using
more » ... our approach using the example of a 4 × 4 switch-and-select (SAS) circuit realized on the silicon photonic platform. We further present a comprehensive graph-theoretical analysis of different n × n SAS circuit topologies. We find that for increasing port counts n of the SAS circuit, the number of WGX increases with n 4 , whereas the number of WOP increases only in proportion to n 2 .
doi:10.1364/oe.27.017402 fatcat:5ow6fh6ax5gplblesbko2pevk4