IBM slows light for chips

IBM has unveiled a device capable of delaying the flow of light on a silicon chip, a requirement for allowing computers to one day use optical communications to achieve better performance.

Using optical instead of electrical signals for transferring data within a computer chip might result in significant performance enhancements since light signals can carry more information faster.

However, buffering, or temporarily holding data on the chip, is critical in controlling the flow of information, so a means for doing so with light signals is necessary. IBM’s new device can buffer optical signals on a chip.

Long delays can be achieved by passing light through optical fibres. However, the current delay line devices for doing so are too large for use on a microchip, where space is precious and expensive. For practical on-chip integration, the area of a delay line should be well below one square millimetre and its construction should be compatible with current chip manufacturing techniques.