Wouldn’t a chip work much faster if instead of current, LIGHT were used in the circuit?

Answer

Dear Karel,

Light-based chips are something that scientists are very actively studying. It is a subject that is part of photonics, the science and technology of light.

Your question actually addresses two things: chip speed and heat generation.

1) “Speed”. Photonic systems work using infrared or visible light. The frequency of light is much higher than the frequency of electrical signals. That is why, in principle, you can process much more information per second with a photonic component. We actually call that “capacity”. The speed of the signals is the same for electrical or optical signals, which is the speed of light.

The prime example is optical fibres, over which we can transfer terabytes per second of data. Optical fiber networks are therefore the backbone of the internet. On a copper cable, on the other hand, you can only send a few hundred megabytes to a few gigabytes per second.

But manipulating optical signals has proven much more difficult. One of the problems is that photonic integrated circuits are much larger than electrical ICs. Photonic chips are already being used in communication network applications, but they are still a long way off as processors in your computer.

2) And that brings us directly to heat generation. Light is absorbed in materials and that also causes heating. This heat production is often quite large due to the fact that it is difficult to make optical components smaller than about 1 wavelength (1 micrometer). A possible solution is to use so-called metamaterials; these are artificial materials that consist of very small electrical circuits and far-reaching miniaturization is in principle possible with these materials. That could be a solution.

Kind regards,

Philippe Tassin
Physicist, Iowa State University