Toward fJ/bit optical communication in a chip

This article reviews our recent studies of ultralow-power nanophotonics devices toward implementing a dense optical communication network in a processor chip. A photonic crystal nanocavity that has a very large Q/V is a very promising tool for reducing the energy consumption and footprint related to this goal. We demonstrate that, to fully exploit this merit, it is essential to introduce appropriate cavity designs and device structures tailored for each device type. In this article, we report several examples of photonic-crystal nanocavity devices that exhibit record low consumption energy/power and explain how we have achieved the performance that we describe. These results indicate that current technology enables us to integrate a large number of various wavelength-sized photonic devices with extremely low energy consumption, which will lead to fJ/bit-level optical communication in a chip.