Short article at optics.org from last week that can bring you up to speed on three significant developments in the use of light for information transfer in next-generation computers.
Hot on the heels of its recent demonstration of an all-optical data bus, IBM revealed a silicon photonic switch based on cascaded microring resonators that can route data at speeds of 1 Tbit/s.
Then NEC working with Tokyo Institute of Technology has developed
…[a] device – which has been developed specifically for a 10 petaflop supercomputer that the Japanese government hopes to build around 2010 – [that] uses laser diodes to turn electrical signals into the optical domain, while data is transmitted between neighbouring chips using bundles of optical fibres.
And lastly the Sun/Darpa announcement and their plans.
Sun’s approach will be to construct arrays of low-cost chips linked together optically to create a single “macrochip”. Although the details remain sketchy, it seems likely that Sun will exploit its “proximity communications” technology to develop some sort of optical proximity connection – in other words, the light will be coupled directly between the chips’ edges, rather than via an optical fibre or waveguide.