Researchers at MIT embedded high-speed optoelectronic semiconductor devices, including LEDs, within fibres that, when woven, produce soft, washable smart fabrics.

Traditionally, optical fibres are produced by making a cylindrical object called a preform, which is basically a scaled-up version of a fibre. This preform is then heated and pulled downward under tension, resulting in the fibre, which is then collected on a spool.

To make the new fibres the researchers added preform light-emitting semiconductor diodes (LEDs) the size of a grain of sand and a pair of copper wires a fraction of a hair’s width. During the fibre drawing process, the polymer perform was heated and partially liquefied, forming a long fibre with the diodes in its centre, connected by the copper wires.

The researchers used two types of electrical diodes, which were made using standard microchip technology: light-emitting diodes and photosensing diodes. By incorporating the devices in the fibre, they become waterproof. The fibres are then woven into fabrics.

The textile was washed ten times to demonstrate their practicality. In addition, the team placed some of fibres in a fish tank. Through rapid optical signals, a lamp outside the aquarium transmitted music through the water. The fibres converted the light pulses, which are so rapid that it looks like steady light to the naked eye, into electrical signals and then into music. You can hear Handel’s Water Music playing in the video below.

The main issue in the research was to make the fibres work consistently, and to make sure that they could be produced reliably and in quantity. Now that hurdle has been taken, the researchers plan to bring the first commercial products to the market as early as next year. The fibres could be used for communication purposes in for instance the military, but there are also biomedical uses, like monitoring pulse or blood oxygen levels.

Photos: MIT