A Novel Two-Layer Passive Optical Interconnection Network for On-Chip Communication

Passive optical interconnection network (OIN) plays a key role in optical Network-on-Chip (ONoC) architecture. Existing passive OINs based on wavelength division multiplexing (WDM) are popularly employed. However, the scalability of these passive OINs is limited by the number of wavelengths and large insertion loss induced by the waveguide crossings. In this paper, we propose a novel Passive OIN based on two-layer architecture, POINT, for ONoC architecture. POINT leverages space division multiplexing (SDM) to assist WDM in eliminating blocking. The inter-layer communication in POINT relies on the inter-layer coupler, which contributes to reduce crossing losses. POINT features a modular and scalable design, in which the proposed SDM-based cell (SBC) is used as the basic building block to construct POINT with efficient wavelength assignment. Furthermore, SBCs of different sizes provide different options for constructing POINT. Comparisons with existing passive OINs confirm that POINT can provide an optimal choice with the balance between the number of wavelengths, area overhead, and insertion loss for the same size.