Chip-scale multiwavelength sources

The fabrication of ultrafast chip-to-chip optical data communications is a step closer, thanks to two independent studies published online this week in Nature Photonics. Both studies report multiple-wavelength light sources integrated onto a silicon chip. These results will not only be useful for improving computing power, but also other applications such as sensing and metrology.

As computer processing power continues to increase, new methods for efficiently passing vast amounts of data around circuit boards are required. Metallic tracks, which are currently used, struggle to keep up with these needs.

The on-chip light sources developed by David Moss and Michal Lipson, and their respective colleagues, can simultaneously transmit multiple data channels in a single optical fibre, each using a different wavelength. Though sources giving multiple wavelengths are already known, these two teams have developed them on a chip that, in principle, can not only be integrated with silicon computer chips, but can be also fabricated using the same methods.

Both devices are based on the similar technology, though each uses different materials to create the multiple wavelengths; Moss's uses a special silica glass, whereas Lipson's uses silicon nitride.