It seems reasonable to assume that for the foreseeable future, the electronic transistor will be superior to its optical equivalent in terms of size, ease of VLSI integration, and power consumption. Given this assumption, the working group believes it is reasonable to assume that the CPUs of computers will remain electronic for some time. At the same time, because of the high bandwidth achievable in optical devices, it seems reasonable to assume that they will be used in simple and regular architectures. These include neural networks and communications-intensive applications, such as data communications switching in which optical switching could avoid a massive number of photon/electron conversions. Therefore, optical switching might have some role to play in PetaFLOPS computers, e.g., controlling high-speed networks, but will not likely be used for the central processors.
