In another potential fibre optic breakthrough, researchers at the University of Michigan at Ann Arbor have developed fibres that can process light signals as well as transmitting them, making possible a new class of integrated circuits that would process data electronically by transmit it optically. The problem has been to align the optical fibre to the tiny light-emitting element in the chip, and the Michigan solution is to grow a photosensitive crystal directly onto a hollow glass fibre. The semiconductor element is then created by directing a beam of Gallium Arsenide molecules at a narrowed section of the glass fibre tube to build a single crystal of GaAs. Some light leaks through the narrowed portion of the tube and into the GaAs crystal, where it is converted into an electrical signal that can be amplified and processed. It is a long way from that to a full-scale electro-optical computer, but the technique promises a major step on the road to building such a machine.
