Compact High‐Power Visible Laser Diode Wavelength Division Multiplexing for White‐Light Communication

Abstract

For compact ultrahigh‐power lighting and high‐speed optical wireless communication (OWC) purposes, the red/green/violet laser diodes (R/G/V‐LDs) moduled with specific Subminiature A (SMA) connectors are used for cold white‐light mixing and direct digital encoding. Even with hybridizing a high‐power yellow light‐emitting diode (LED) for high color‐rendering index lighting, such a R/G/V/Y design can miniaturize its volume to W × L × H = 6 × 5.4 × 2 cm3 (only 1/310 of the conventional bulky setup). The R/G/V‐LDs are individually encoded by 16 quadrature amplitude modulation orthogonal frequency‐division multiplexing (16‐QAM OFDM) data to demonstrate the visible wavelength division multiplexing (VWDM). Such R/G/V‐LD VWDM transmitters provide 8.8/5.2/7.2 Gbps modulation to achieve the total data rate as high as 21.2 Gbps after employing the power preleveling technique. Such high‐power R/G/V‐LDs under optimized bias currents deliver an output power of 102/97/129 mW, which can offer a high illuminance of 12 800 lux within a divergent angle of 54° at a distance of 0.5 m. To date, such ultrahigh‐power compact R/G/V‐LDs with lighting VWDM capability beyond 20 Gbps also enable the possibility of network coverage for B5G/6 G and Industry 4.0 applications.