2 Gbit/s data transmission from an unfiltered laser-based phosphor-converted white lighting communication system

Area of Science:

• Optoelectronics
• Solid-state lighting
• Optical communications

Background:

• Visible light communication (VLC) systems typically use light-emitting diodes (LEDs) for illumination and data transmission.
• Gallium nitride (GaN) laser diodes (LDs) offer potential advantages in modulation bandwidth and efficiency over LEDs.
• Integrating LDs with phosphors for white light generation presents challenges in achieving high-speed data transmission and stable illumination.

Purpose of the Study:

• To demonstrate high-speed data transmission using unfiltered white light generated by a GaN LD and YAG:Ce phosphors.
• To evaluate the performance of this system for simultaneous illumination and indoor broadband access.
• To assess the color properties and stability of the generated white light.

Main Methods:

• Direct modulation of a blue GaN laser diode (LD) to excite Y3Al5O12:Ce (YAG:Ce) phosphors for white light generation.
• Utilizing a non-return-to-zero on-off keying (NRZ-OOK) modulation scheme for data transmission.
• Measuring modulation bandwidth, data transmission rate, and bit error rate (BER) without an optical blue-filter.

Main Results:

• Achieved a modulation bandwidth of 1.1 GHz, not limited by the phosphor response.
• Demonstrated a data transmission rate of 2 Gbit/s with a BER of 3.50 × 10(-3), below the forward error correction (FEC) limit.
• Generated white light with CIE 1931 chromaticity coordinates (0.3628, 0.4310), a color rendering index (CRI) of 58, and a correlated color temperature (CCT) of 4740 K at 300 mA LD current.

Conclusions:

• The demonstrated laser-based lighting system enables high-speed data transmission using unfiltered white light.
• The system is suitable for simultaneous indoor broadband access and illumination applications.
• Good color stability was observed, making it a viable option for integrated communication and lighting solutions.