White-Lighting Communication with a Lu3Al5O12:Ce3+/CaAlSiN 3:Eu2+ Glass Covered 450-nm InGaN Laser Diode

By using the Lu₃Al₅O₁₂:Ce³⁺/CaAlSiN₃:Eu²⁺ phosphor codoped fluorescent glass as a phosphor in front of an InGaN laser diode (LD), a novel white-lighting and visible light communication (VLC) module is demonstrated. By enlarging the fluorescent glass thickness from 0.7 to 1 mm, the CCT of the generated white light is increased from 7373 to 25000 K, and the maximal illuminance is enlarged from 1306 to 1356 lux. The pure LD-beam-based VLC can lengthen its transmission distance from 0.5 to 16 m, associated with allowable data rate slightly decreased from 14.8 to 10.8 Gb/s. When using the divergent white light as a carrier for VLC transmission, the allowable data rate upgrades from 1.6 to 4.4 Gb/s within 0.5-m distance in free space by thinning the fluorescent glass from 1 to 0.7 mm. Lengthening the white-lighting distance to 1 m for the VLC system still permits 16-QAM OFDM data transmission as high as 2.8 Gb/s. Such a Lu₃Al₅O₁₂:Ce³⁺/CaAlSiN₃:Eu²⁺ phosphor codoped fluorescent glass not only converts the blue LD beam for white lighting efficiently, but also preserves sufficient data capacity with acceptable signal-to-noise ratio for indoor VLC application.