Towards femtojoule-per-bit optical communication in a chip

This paper reviews our recent studies of ultralow-power nanophotonics devices towards implementing a dense optical communication network into a processor chip. A photonic crystal nanocavity that has a very large Q/V ratio is a very promising tool for reducing the consumption energy and footprint for this goal. We show several examples of photonic-crystal nanocavity devices that exhibit record-low consumption energy/power and describe how we have achieved the performance. These results indicate that the present technology is now enabling us to integrate a large number of various wavelength-sized photonic devices with extremely-small energy consumption, which will lead to fJ/bit-level optical communication in a chip.