Optical computers promise to process data at the speed of light, but the biggest problem facing their development is that the technology cannot be miniaturised to the scale needed by the microelectronics industry.
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The Engineering and Physical Sciences Research Council (EPSRC) is funding a £6m programme at Queen's University Belfast and Imperial College London to investigate an alternative way of building optical computers using nanoplasmonic devices, which are similar to optical components but far smaller.
At present, the speed at which computers process information is limited by the time it takes for the information to be transferred between electronic components. To speed up the process, scientists at Queen's and Imperial hope to develop a way of sending the signals along the same wires using light waves.
To achieve this, the researchers are developing a raft of metallic devices, including tiny nanoscale sources of light, nanoscale waveguides to guide light along a desired route, and nanoscale detectors to pick up the light signals.
The devices will use waves of electrons, known as plasmons, which are created when light hits the surface of a metal. Nanoplasmonic devices use tiny nanoscale metal structures - more then 100 times smaller than the width of a human hair - to guide and direct light.
While optical transistors need to be 20cm in size, Anatoly Zayats (pictured), a professor at Queen's University's Centre for Nanostructured Media who leads the project, says nanoplasmonic devices are tenths of a nanometer in size, making them ideal for future microprocessors.
This is because optical circuits require a coupler, which converts the optical signal to an electronic signal. But in nanoplasmonic devices, Zayats says light is coupled with electons in a metal waveguide, allowing the light to be squeezed into extremely small dimensions. This means they could one day be used to build new kinds of super-high-speed optical computers.
Similar approaches may also help in the development of devices for faster internet services.
Power and speed
The first step in the project is to produce a source of plasmons, which will work in a similar way to lasers in optical circuits, to encode data.
From there, Zayats says, "We will look at different approaches to industrialisation, including standard photo-lithography, which is compatible to the way microelectronic devices are fabricated today."
Professor Stefan Maier, who leads the research team at Imperial, says, "This is an exciting step towards developing computers that use light waves, not electrical current, to handle data and process information. In the future, these optical computers will provide us with more processing power and higher speed. This will also open the door to a world of possibilities in scientific fields at the interface with the bio-sciences, and perhaps even in the world of personal computing."
The project is being supported by Intel, Seagate, Ericsson, Oxonica, IMEC and the National Physics Laboratory.