On-Chip Optical Routing With Provably Good Algorithms for Path Clustering and Assignment

Abstract

As the VLSI technology continues to scale down, combined with increasing demands for large bandwidth and low-power consumption, the optical interconnections with wavelength-division multiplexing (WDM) become an attractive alternative for on-chip signal transmission. Previous WDM-aware optical routing works consist of three main drawbacks: they are based mainly on heuristics or restricted integer linear programming to handle optical routing, the addressed types of insertion loss, and WDM overheads are incomplete, and the crosstalk noise during concurrent signal transmission is neglected. As a result, no performance guarantees can be achieved on their WDM clustering results, the reliability of the optical network is impaired, and/or their computations are too time consuming. To remedy these disadvantages, we present a new WDM-aware optical routing flow to minimize the insertion loss, the WDM overheads, and the crosstalk noise with a significant speedup. In the proposed flow, the WDM-aware path clustering algorithm guarantees to find an optimal solution for 1-, 2-, and 3-path clustering and has the constant performance bound for most cases of 4-path clustering; the crosstalk-aware path assignment guarantees to minimize the number of crosstalk signal pairs within the given displacement bound. Experimental results based on the ISPD 2007 and 2019 contest benchmarks and a real optical design show that our optical router significantly outperforms published works in wirelength, insertion loss, wavelength power, crosstalk noise, and runtimes.