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 our sister site 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.
Jeff Hecht, New Scientist