Photonics to supersede electronics in processors

Computers could run on light instead of electronics, according to researchers at Bath University.

Computers could run on light instead of electronics, according to researchers at Bath University.

An £820,000 Bath research project begins soon which could be an important step in developing photonic computers – devices run on light rather than electronics.

Physicists at the university will be looking at developing attosecond technology – the ability to send out light in a continuous series of pulses that last only an attosecond, one billion-billionth of a second.

The researchers said the project could not only develop the technology of photonics, but also give physicists the chance to look at the world of atomic structure very closely for the first time.

In June, Fetah Benabid, of the Department of Physics at Bath, will lead a team of researchers to develop a technique to synthesise “waveforms” using light photons with the same accuracy as electrons in electronics.

Waveform synthesis is the ability to control very precisely the way that electric fields vary their energy.

Ordinarily, electric fields rise and fall in energy in a regular pattern similar to the troughs and crests of waves on the ocean, but modern electronics allows a close control over the shape of the “wave” – in effect creating waves that are square or triangular or other shapes rather than curved.

It is this control of the variation of the electric field that allows electronic devices such as computers to function in the precise way needed.

But electronics has its limitations, the researchers point out. The development of ever smaller silicon chips, which has allowed computers to double in memory size every 18 months or so, will come to a stop in the next few years, they claim, because the laws of physics do not permit chips smaller than a certain size.

Instead, engineers are now looking to photonics, which uses light to convey information, as a much more powerful alternative. But so far, the ability of photonics to use light in a single waveform only – a curve known as a sine wave – has limited value for the communications needed to operate a computer, for instance.

The Bath researchers want to allow photonics to create waveforms in a variety of different patterns. To do this, they are using photonic crystal fibres, which are a great step forward in photonics because, unlike conventional optical fibres, they can channel light without losing much of its energy.

In the research, light of one wavelength will be passed down a photonic crystal fibre which then branches off in a tree-like arrangement of fibres, each with a slightly separate wavelength, creating a broad “comb-like” spectrum of light from ultraviolet to the middle of the infrared range.

This broad spectrum would allow close control over the electric field, which is the basis of conveying enormous amounts of information that modern devices like computers need.

The researchers are funded by a grant from the Engineering and Physical Sciences Research Council.

“Harnessing optical waves would represent a huge step, perhaps the definitive one, in establishing the photonics era,” said Benabid. “Since the development of the laser, a major goal in science and technology has been to emulate the breakthroughs of electronics by using optical waves. We feel this project could be a big step in this. If successful, the research will be the basis for a revolution in computer power as dramatic as that over the past 50 years.”

A continual series of short bursts of light would not only dramatically affect technology - it would also advance physics by giving researchers the chance to look inside the atom.

Although atoms can now be “seen” using devices such as electron microscopes, it has not been possible to examine their fast dynamics. By sending light in short bursts into an atom, the researchers will be able to work out the movements of electrons, the tiny negatively charged particles that orbit the atom’s nucleus.

This may, literally, throw light on the strange quantum world of subatomic particles, which have no definite position, but are only “probably” in one place until observed.


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