Silicon Photonics: The System on Chip Perspective

Abstract

This chapter describes possible applications of silicon photonics to the System on Chip (SoC) domain. Systems on Chip (SoCs) are complex systems containing billions of transistors integrated in a unique silicon-chip, implementing even complex functionalities by means of a variety of modules communicating with the system memories and/or between them through a proper communication system. The higher and higher integration density is becoming such that many issues arise when a SoC has to be integrated, and electrical limits of interconnect wires are a limiting factor for performance. According to this scenario, a new technology is required for the on-chip interconnect, in order to overcome current physical and performance issues; one possible solution is the optical interconnect, exploiting the many benefits of light to transport information across the chip. From an industrial point of view it is fundamental that such a new technology be fully CMOS compatible, in order to be able to continue to use current SoC design methodologies as well as present manufacturing equipment for the whole electronic part of the chip. Many semiconductor industries are today investigating such a novel field and a number of projects are currently running in order to demonstrate the feasibility of such a revolutionary on-chip communication system relying on both CMOS technology and photonics.