Researchers at Siemens have transmitted data via polymer optical fibre (POF) cable at over 1Gbit/s, opening up new opportunities for the technology in factory automation, easy-to-build home networks linking PCs and high-definition TVs, and in-vehicle networking.
"Polymer cable enables do-it-yourself installations," says project manager Sebastian Randel. Unlike optical fibre made from glass, "It's flexible and it's easy to cut and insert in connectors."
The POF cable is around 1mm thick, doesn't break easily and can be cut with a razor blade, according to Randel. However, it is currently limited to Fast Ethernet speeds, as its transmission loss is far higher than that of glass fibre.
By comparison, although glass fibre can carry data at much higher speeds, it is also much thicker once wrapped in a protective shield, and it breaks if bent too tightly, Randel says. Cutting it cleanly to attach connectors or make joints requires a diamond blade, he adds.
POF is also relatively inexpensive, and this — along with its robustness — has already made it popular for home and automotive networking.
Demand for easy-to-install, low-cost home networking systems is growing as new high-speed services such as IPTV (Internet Protocol television) hit the market. While Wi-Fi eliminates the need for cables altogether, it can't guarantee constant and robust transmission required for services such as IPTV, according to Randel.
The Siemens researchers transmitted TV signals at 1008Mbit/s over a 100m test network, without errors or flickering on the screen, he says.
Rather than transmit each bit as a pulse of light, they modulated the light signal using the same quadrature amplitude modulation technique that is used by DSL (Digital Subscriber Line). This has up to 256 signal states, which allows each pulse of light to carry several bits of information.
In addition to home networks, POF cable is also used in other areas where rugged, low-cost cables are required, such as in factories and inside cars and trains.
Randel is unable to say when a 1Gbit/s polymer cable product would be available or what it would cost, but says the Siemens research proved that the technology works.