Optics for Low-Energy Communication Inside Digital Processors: Quantum Detectors, Sources and Modulators as Efficient Impedance Converters.

I argue that optics can reduce the energy for irreversible communication of logic signals inside digital switching and processing machines. This is because quantum detectors, sources and modulators can perform an effective impedance tranformation that matches the high impedances of small devices to the low impedances encountered in electromagnetic propagation. Current physics and device concepts are sufficient to realize this advantage over electrical communications. This energy argument suggests that all except the shortest intra-chip communications should be optical.