From Darwin to Internet at the speed of light

Internet traffic jams may become history if ESA succeeds in developing new technology to see nearby Earth-sized planets. Why? In looking for new ways to detect planets ESA is thinking that, instead of bulky mirrors and lenses in space, one can build miniaturised optical systems that fit onto a microchip. Such ‘integrated optics’ would also allow earthly computer networks to use high-speed routing of data streams as a natural spin-off.

Data moving around the Internet are like road traffic in that a car can be driven fast down a straight road but has to slow down a great deal when changing direction at a junction. The same thing happens on information highways. Beams of light carry data along fibre-optic cables at very high speeds. When the data arrive at computers, known as servers, the servers redirect them to their final destinations. Presently, you need to convert the light signals into electricity, and that slows everything down.

Electrons move at a speed of a few kilometres per second through a circuit, whereas light travels at nearly 300 000 kilometres per second. Integrated optics would leave the data as light and simply channel it through the chip, in the right direction. Scientists call this area integrated optics, referring to the integrated circuit board on which chips are mounted. Instead of miniaturised electronics, however, miniaturised optics are placed on a microchip.

ESA has a strategy to enable more sophisticated searches for extra-solar planets in the future. Two planned developments rely on combining the light from such planets in a number of different telescopes. These are the Darwin mission and its precursor, the ESA/ESO Ground-based European Nulling Interferometer Experiment (GENIE).

When you combine light beams, you traditionally need moving mirrors and lenses to divert the light beams to where you want them. However, if the system moves, it can break. As Malcolm Fridlund, Project Scientist for Darwin and GENIE says, “To change to integrated optics, which is much smaller and has no moving parts, would be highly desirable.”

Desirable certainly, but also difficult. At present, integrated optics is a science that is far behind integrated circuit technology. For this reason, ESA is funding two studies. Astrium has been asked to study a traditional optics approach and Alcatel is investigating an integrated-optics solution. “We shall take the decision on whether GENIE will use integrated optics in just over one year,” says Fridlund.

In the future, Darwin, ESA’s ambitious mission to find Earth-like planets, may also use integrated optics but using longer wavelengths of light than GENIE. This is uncharted territory as far as integrated optics is concerned. However, Fridlund is currently reviewing proposals from industrial companies which would like to take up the challenge. “What I’’m reading in those proposals is making me highly optimistic,” says Fridlund, “I don’t yet know whether mid-infrared integrated optics will have any commercial application, but until we develop them, we’ll never know.”

Should the integrated-optics approach work, the rewards would extend far beyond a few improvements in searching for planets. Here on Earth, for all home-computer users, for example, it could speed up the Internet by 100–1000 times. The consequences of surfing the Web at such speeds would be amazing.