A 1.6pJ/b 65Gb/s Si-Dielectric-Waveguide based Multi-Mode Multi-Drop sub-THz Interconnect in 65nm CMOS

Ever-increasing data generation and transmission demands have been driving great advancements in wireline communications from both electrical interconnect (E1) [1] and optical interconnect (O1) [2] for short- and long-distance scenarios, respectively. In the meter range, both El and Ol face great challenges: the lossy and bandwidth-limited channel is the bottleneck of El; For Ol, the features, such as the complex fabrication and high environment sensitivity, increase the power and cost budgets significantly, making it less economical for short-distance communications. To mitigate these issues, low-loss dielectric channel-based interconnects have been investigated and demonstrated [3] –[5]. However, they are all for point-to-point configurations, not suitable for multi-drop distributed architectures as shown in Fig.1. Thus, the unscalable feature limits their deployments. To address this important challenge, this paper adopts spatial multiplexers [6] and presents a Si dielectric waveguide (DWG) based multi-mode multi-drop sub-THz interconnect with great scalability for numerous ports and multi-dimensions. This approach is also more power and cost effective compared to Ol due to the elimination of exotic materials and devices, such as lasers and OE/EO, and sophisticated fabrications. lt only needs a low-cost and standard fabrication process with coarse alignment requirement.