Multiplexing in photonics as a resource for optical ternary content‐addressable memory functionality
Yanir London, Thomas Van Vaerenbergh, Luca Ramini, Antoine Descos, Luca Buonanno, Jinsung Youn, Can Li, Catherine E. Graves, Marco Fiorentino, Raymond G. Beausoleil
Abstract
Abstract In this paper, we combine a Content‐Addressable Memory (CAM) encoding scheme previously proposed for analog electronic CAMs (E‐CAMs) with optical multiplexing techniques to create two new photonic CAM architectures—wavelength‐division multiplexing (WDM) optical ternary CAM (O‐TCAM) and time‐division multiplexing (TDM) O‐TCAM. As an example, we show how these two O‐TCAM schemes can be implemented by performing minor modifications in microring‐based silicon photonic (SiPh) circuits originally optimized for exascale interconnects. Here, our SiPh O‐TCAM designs include not only the actual search engine, but also the transmitter circuits. For the first time, we experimentally demonstrate O‐TCAM functionality in SiPh up to and we prove in simulation feasibility for speeds up to 10 Gbps, 10 times faster than typical E‐TCAMs at the expense of higher energy consumption per symbol of our O‐TCAM Search Engine circuits than the corresponding E‐TCAMs. Finally, we identify which hardware and architecture modifications are required to improve the O‐CAM’s energy efficiency towards the level of E‐CAMs.