COMMONLY available laser pointers can zing data
through the air across a room twice as fast as most USB cables or Wi-Fi
routers. The new optical wireless promises to be cheap and easy to roll
out in hospitals and other places where radio transmitters cannot be
used.
Engineers at the National Taipei
University of Technology in Taiwan picked red and green laser pointers
because they are cheap and easy to get hold of. The hardware used in a
demonstration cost only about $600, says Hai-Han Lu, who led the work. "Hobbyists could do this at home," he told New Scientist.
The team replaced the pointers'
standard batteries with a power source that switched each laser off and
on 500 million times a second, and aimed two pointers at a
light-sensitive detector 10 metres away. After processing, the signals
contained less than one error per billion bits, a sign of high-quality
transmission. Combining the two signals yielded a billion bits per
second, double the data rates of USB 2.0 or high-speed radio-based Wi-Fi
(Optics Express, vol 20, p 9919).
Fog, rain and snow make long-distance
laser links through air impractical, but they could work for indoor use.
A system along these lines could one day be useful for high-speed
connections between smartphones.
