Impact of Topology on the Scalability of Mach-Zehnder-Based Multistage Silicon Photonic Switch Networks

We analyze the scalability of electro-optic Mach-Zehnder-based silicon photonic switch networks. We describe a simulation framework based on the transfer matrix method that enable to model any type of multistage networks. We simulate three common network topologies - Beneš, path-independent loss, and double-layer - and analyze their scalability by performing optical link numerical simulations for 50 Gbps non-return-to-zero signals. Our study shows that for a radix-16, the double-layer network performs better with a link power penalty smaller than 1 dB thanks to its dilated arrangement. For equivalent radix, the Beneš and path-independent loss networks have link power penalties larger than 4 dB. Our simulations also show stringent requirements for the waveguide crossing crosstalk, whose value should be smaller than -35 dB to close any realistic link budget.