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.
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.
Future microprocessors
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.