On-chip electrical links exhibit large energy-to-bandwidth costs, whereas on-chip nanophotonics, which attain high throughput, yet energy-efficient communication, have emerged as an alternative interconnect in multicore chips. Here we consider silicon nanophotonic components that are embedded completely within the silica (SiO2) substrate as opposed to existing die on-surface silicon nanophotonics. As nanophotonic components now reside subsurface, within the silica substrate, non-obstructive interconnect geometries offering higher network throughput can be implemented. First, we show using detailed simulations based on commercial tools that such Silicon-in-Silica (SiS) structures are feasible, and then demonstrate our proof of concept by utilizing a SiS-based mesh-interconnected topology with augmented diagonal optical channels that provides both higher effective throughput and throughput-to-power ratio versus prior-art. Copyright is held by the owner/author(s).