Researchers at Ghent University in Belgium have etched a tiny world map–on a scale of 1 trillion—on to a optical silicon chip. They reduced the earth's 25,000-mile circumference at the equator down to 40 micrometers or about half the width of a human hair to fit it on the chip.

The map is put in a corner of a chip designed for a project at the University's Photonics Research Group.

The idea is to successfully demonstrate scale reduction so complex optical functions can be included in a single chip. Such a chip could find applications in telecommunications, high-speed computing, biotechnology and health care.

The world map was defined on a silicon photonics test chip using 200mm processing. The smallest features resolved on the map are about 100 nanometer. The fabrication consisted of a 30-step process and involved creation of four different layers with differing thicknesses, each of which had to be created separately.

Photonics involves generation, modulation, transmission and processing of light. Silicon photonics technology is an emerging area of research that integrates optical circuits onto a small chip. Light can be manipulated on a submicrometer scale in tiny strips of silicon called photonic wires. These silicon photonic circuits can pack a million times more components when compared to the glass-based photonics available currently, say the researchers.

The circuits developed on this chip carrying the world map were used to demonstrate photonic wires with the lowest propagation losses.

Photo: The small world as seen through an optical microscope. The different colors are caused by interference effects in the different layer thicknesses of the silicon (Photonics Research Group at Ghent University)