Populating and exploring the design space of wavelength-routed optical network-on-chip topologies by leveraging the add-drop filtering primitive

Emerging technologies often carry different logic primitives for which contemporary logic synthesis techniques are not suitable. For this reason, the design space of circuit-level solutions relying on such technologies is often largely unexplored. One domain where this trend is evident consists of topologies for wavelength-routed optical networks-on-chip (WRONoCs). Current literature only reports isolated design points that are inspired only by the intuition of researchers: there are currently no methodologies that enable designers to populate the design space in a consistent way. As a result, the possibility of an automated synthesis flow guiding the designer to the most promising solution in the design space is far from coming. This paper aims at bridging the former gap by identifying the basic primitive which is at the core of each topology. Then, a methodology is consistently derived to combine basic primitives together, thus potentially yielding all points of the topology design space. To our knowledge, this is the first time the design space of wavelength-routed topologies is populated in a potentially exhaustive way through a systematic methodology. As a result, it becomes evident that for a specified quality metric, there exist better solutions than the topologies that have been found out so far by designers' intuition. This paper is thus the stepping stone for future work targeting automatic synthesis of WRONoC topologies.