Computer Chips Communicating With Light
Sat, 23rd Sep 2006
Part of the show Catalysts for Cleaner Environments and
As computer chips get faster and faster moving information around them is getting more difficult, as sending information very fast electrically uses lots of energy. One solution is to use light to communicate, you can transmit far more information with much lower energy losses - this is actually how information is moved long distances, between mobile phone masts, across the atlantic etc.
There is however a major problem, computer chips are made of silicon, but you can't make a laser out of silicon, instead of getting light out you just get heat. There are other semi-conductors which work well such as Gallium Arsenide, ore Indium Phosphide, but you can't grow them on a silicon wafer as the distance between the atoms is different, so it would be like tring to fit 2 lego bricks on top of each other, one 20% bigger than the other.
John Bowers in the university of California Santa Barbra may have the solution. Make some Indium phospide and some silicon increadibly smooth and clean, oxidise them a bit, then just push them together and they stick. This way you can use the right material for making the laser on a standard silicon chip. He ahs put 26 lasers on a chop but is hoping to scale it up to thousands, leading to faster computers.