Light-Based Computing Promises Super Speeds

John Lister's picture

A computer that uses light - rather than electrons - for processing could be faster, smaller and use less power. Researchers say they've found a way to make an optical computer without the major limitations of previous models.

Ultimately, everything a computer does is broken down into a series of calculations. In traditional computer processors, these work through a series of physical "logic gates" that either do or don't pass through an electrical signal. This creates a positive or negative electrical charge, which represents either a 0 or 1 in a single bit of data.

Several researchers have worked on the idea of an optical computer that uses light rather than the electrical signal. The idea is that light not only moves faster than the electrons used in traditional computing, but isn't limited by electrical resistance. That means it takes less power to operate.

Previous attempts to create optical computers have been relatively bulky and only work on specific tasks, making them an inadequate alternative to traditional computers.

Spin Direction Determines Data

A team led by Yi Zhang at Finland's Aalto University say they've found a way through these problems with a new design of optical computer. They've used circularly polarized light which, in simplified terms, manipulated the light beam to "spin" in a clockwise or anti-clockwise manner. The direction of the spin ultimately corresponds to the 0 or 1. (Source:

The team's design means each "logic gate" is just 0.65 nanometers thick. A nanometer is one millionth of a millimeter. The design is not only more practical than previous optical computers, but also means it can be used for any computing task.

One Million Times Faster

How well the design would work in a real-world computer has yet to be confirmed, as have the cost implications. However, in principle the design could mean processing data a million times quicker than with existing tech. (Source:

At the moment the optical computer only replicates the traditional approach to computer processing data where a single "core" of a processor can only handle one bit of data at any precise moment.

The team behind it say they'll now explore how the optical technology could adapt to parallel processing (where it performs multiple calculations at once) or even quantum computing (where a single gate could correspond to multiple states simultaneously).

What's Your Opinion?

Are you excited by this technology? Would a computer running a million times faster really make any difference to your experience? Do you think we'll ever see optical computer in mainstream use?

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Average: 4.9 (8 votes)


Phil's picture

From the outset, when the author claimed that light travels faster than electronic signals - they travel at the same speed - this article had my BS meter set to high. Other than the miniaturization of a logic gate, nothing in this piece about accelerated simultaneous computing passes the smell test. It sounds like the worst kind of Star Trek jargon soup. That's fine for a sci-fi show, which is really about the people, not the tech, but not ok for "science reporting."

ron_weiskopf's picture

The speed of light is considerably faster than the propagation speed of electrical currents. That speed depends a lot on the physical properties of the circuit, but I've seen things like 100 times slower than light. What you might be confusing is that the electrons go close to the speed of light, but they are bouncing back and forth and don't go forward nearly as fast.

Phil's picture

When it comes to information transmission, no one cares about the speed of individual electrons or photons - it's the signal that travels at the speed of light.

Think about the experiment with three coins on a table B and C touching. Hold down B and strike it with A - C will fly away even though B has not visibly moved at all.

Waves move across oceans without the need for the body of water to move laterally.
It's the rate of propagation of information that matters, and electrical information, like radio waves, moves at the speed of light.

buzzallnight's picture

Fiber optic cable is faster with less loss over distance than copper wire.