Optical wireless communications

VLC systems take advantage of light-emitting diodes (LEDs) which can be pulsed at very high speeds without a noticeable effect on the lighting output and human eye.

These systems typically use laser transmitters and offer a cost-effective protocol-transparent link with high data rates, i.e., 10 Gbit/s per wavelength, and provide a potential solution for the backhaul bottleneck.

There has also been a growing interest in ultraviolet communication (UVC) as a result of recent progress in solid-state optical sources/detectors operating within solar-blind UV spectrum (200–280 nm).

[4] In 1810, Carl Friedrich Gauss invented the heliograph which uses a pair of mirrors to direct a controlled beam of sunlight to a distant station.

For example, in 1935, the German Army developed a photophone where a tungsten filament lamp with an IR transmitting filter was used as a light source.

In 1962, MIT Lincoln Labs built an experimental OWC link using a light-emitting GaAs diode and was able to transmit TV signals over a distance of 30 miles.

[8] OWC’s mass market penetration has been so far limited with the exception of IrDA which is a highly successful wireless short-range transmission solution.