White-light color conversion with red/green/violet laser diodes and yellow light-emitting diode mixing for 34.8  Gbit/s visible lighting communication

The visible wavelength-division multiplexing (VWDM) optical wireless communication beyond 30 Gbit/s with a white-light beam mixed by red/green/violet (R/G/V) laser diodes (LDs) and yellow (Y) LED is demonstrated via quadrature amplitude modulation discrete multitone modulation (QAM DMT). To facilitate both high-quality indoor lighting and high-speed optical wireless communication, the R/G/V-LD white-light module incorporates with a Y-LED to provide a high color rendering index (CRI) and encapsulates with a frosted glass to enlarge its divergent angle. By respectively encoding the R/G/V-LDs with the filtered QAM DMT data in a back-to-back case, the total raw data rate as high as 34.8 Gbit/s is achieved by encoded R/G/V-LDs with respective VWDM data rates of 18/7.2/9.6 Gbit/s. To fulfill the demanded CRI and correlated color temperature (CCT) for indoor white-lighting, the yellow LED contributes the yellowish-orange luminescence with flexible CCT and CRI varying from 3952 K to 3031 K and from 0 to 45.9, respectively. A cold white-light carrier at a CCT of 4852 K, CRI of 71.6, and CIE of (0.3652, 0.4942) is also approached by attenuating the red LD power, and such a cold white-light spot with an illuminance of 6800 lux and a divergent solid angle of 0.89 steradian (sr) can support VWDM data transmission at 28.4 Gbit/s.