Photonics

Photons may not replace electrons in data process- ing and storage this cen- tury, but there are reliable indications that they will be used increasingly in data communications via optical-fibre cables. And, of course, they are already in use in the remote con- trol of countless hi-fi and television sets; they are also indispensable in the Strategic Defence Initiative (Star Wars). There is also the photonic computer now being developed at Heriot-Watt University, Edinburgh, and at the Bell Laboratories in Princetown, New Jersey. These computers use transphasors, the optical equivalent of transistors. Their main attraction is that they can work thousands of times faster than electronic ones because, although elec- trons, under ideal con- ditions, move almost as fast as light, they are slow- ed down to a per cent or two of that speed in silicon. However, we will not be able to give a description of the photonic computer until that has been un- veiled in some twelve to eighteen months...