Modern computers rely on electrons moving through wires to transmit information, which is far, far slower than the fast-as-light optics we theoretically could be using. And now we’ve found the exotic material that might allow us to leave electrons behind.
Electrons may be the lifeblood of computer communications, but they have a dirty little secret: they’re actually pretty damn slow. Scientists and engineers would like to switch to entirely optical communications, which could, naturally enough, travel at the speed of light. The current target is known as “wireless interconnecting”, in which information is communicated at speeds 100 to 1000 times faster than is possible with current electronic technology.
The main hurdle isn’t transmitting the data from one point to another – it’s creating a receiver that can understand the information as fast as it’s sent. Since the only signal processing we currently understand is electronic in nature, it doesn’t matter how fast the optical communications are because all that fast-moving data will come screeching to a halt when it reaches its destination. But if we can find a way to build optical emitters and detectors, then we’d enter an age of computers capable of terahertz speeds. For comparison, modern computers top out at just a few gigahertz, a thousandth of what might be possible with fully optical computing.
That’s where a tiny, nanoscale device made from the compound gallium arsenide comes into the picture. A research team from Oregon State University, the University of Iowa and Germany’s Philipps University have discovered these little devices can handle terahertz pulses for very short stretches, allowing them to process and control electrical signals in a semiconductor.
That means they’re fast enough to do the job of optical computing, and now it’s just a question of refining them so that they can handle the task for longer periods. They also need to figure out how to make the stuff work at higher temperatures – the experiments were performed inside the super-coolant liquid helium, which isn’t really a practical casing for the average computer user.
Still, the researchers feel cautiously confident they’ve created what they call “the first building block of optical signal processing”. There are a lot of potential applications for this, including in video and audio devices that could make use of the greater speeds optical communications provide. But the real next step will be putting terahertz processors to work in quantum computers, which would need to be phenomenally fast anyway. Gallium arsenide might just be exactly what’s required.