Hmm... We already can build conduits that are as effective at carrying light as wiring is for carrying electricity, and shielding them from light interference and bleeding is difficult, but not impossible... about the only thing we really need to build an optical computer is an optical transistor that doesn't wear out quickly. So far, nobody has managed to make one that lasts more than a couple thousand switchings.

If they've managed a breakthrough on this, they may actually have something. Last I heard, though, most of the research was going into design modifications that reduced the number of transistor state switichings per calculation, rather than increasing the lifetime of the transistors themselves.