Routing impact of architecture and damage in programmable photonic meshes

Abstract

Programmable photonic integrated circuits (PPICs) emerge as a novel technology with an enormous potential for ground-breaking innovation. Different architectures are currently being considered that dictate how waveguides should be connected to realize a broadly usable circuit. We focus on the effect of varying connectivity architectures on the routing of light. Three types of uniform meshes are studied, and we introduce a newly developed mesh that is called ring-connected straight lines. We provide an analytical formula to calculate exact distances in these meshes and introduce several metrics relating to routing to compare these meshes. We show that hexagonal tiles are the most promising, but the ring-connected straight lines architecture has a use case as well. Besides this, the effect of defect couplers is also studied. We find that the effects of these failures vary greatly by type and severity on the routability of the mesh.