Sci. Rep. 7, 11 (2017)

Colour mixing of light from red, green and blue laser diodes has enabled the demonstration of an indoor white lighting communication link that can operate at data transmission speeds approaching 10 Gbit s−1. The concept of visible light communication, whereby solid-state lighting is used for the dual purposes of illumination and data communication, has become a highly active topic of research in recent years. However, to date, most demonstrations have made use of LEDs as the light source, which severely limits the speed of the data link due to their broad spectral emission, poor directionality and low coherence. Researchers from National Taiwan University in Taipei have now designed and tested a scheme that overcomes these limitations by combining the output from red, green and blue laser diodes using dichroic mirrors to create white light. The drive current to each laser diode is modulated to create a wavelength-division-multiplexed, white-visible-light communication system that can transmit at a data rate of 8.8 Gbit s−1 over a distance of 0.5 m in free space. In terms of illumination, the white light from the system has a colour temperature of 8,382 K and a luminance of 7,540 lux.