On-chip Optical Routing with Waveguide Matching Constraints

Abstract

Photonic integrated circuits (PICs), which introduce optical interconnections for on-chip communication, have become one of the most promising solutions to the increasing requirements with large bandwidth and low-power consumption. Routing techniques for optical interconnections have been proposed to deal with various routing issues in PICs, including transmission losses, thermal reliability, etc. However, in some emerging applications, different optical paths should be closely matched (in terms of the path length, the number of bends, the radius of curvature of bends, and the crossing count) to operate correctly. To the best of our knowledge, no previous work deals with these matching constraints in optical routing. This paper proposes a complete algorithm flow based on an optimal Steiner tree construction and integer linear programming with a hexagonal routing style to handle the matching constraints while minimizing the total transmission loss in a design. Compared with A*-search-based net-matching routing, experimental results show that our optical router can route all nets without violating any matching constraints while achieving lower total/maximum transmission loss, based on the optical netlists from a state-of-the-art work.