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

Aleksandar Nesic,Andreas Hofmann,Tobias Hoose,Matthias Blaicher,Martin Nöllenburg,Matthias Lauermann,Sebastian Randel,Wolfgang Freude,Christian Koos,Yasar Kutuvantavida

doi:10.1364/oe.27.017402

Abstract

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 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 n4, whereas the number of WOP increases only in proportion to n2.

Highlights

Photonic integrated circuits (PIC) are becoming increasingly complex, incorporating thousands of photonic devices on a single chip [1,2]
We experimentally demonstrate the viability of our approach using the example of a 4 × 4 switch-and-select (SAS) circuit realized on the silicon photonic platform
We introduced a concept for realizing photonic-integrated circuits (PIC) with non-planar topologies

Summary

Introduction

Photonic integrated circuits (PIC) are becoming increasingly complex, incorporating thousands of photonic devices on a single chip [1,2]. In the graph drawing of the circuit, all vertices representing input and output ports must be placed on a closed curve that represents the boundary of the chip surface, and no waveguide (graph edge) routing outside the area enclosed by the curve is allowed.

Results

Conclusion