In this paper, we first experimentally demonstrate a 550 Mbit/s real-time visible light communication (VLC) system based on nonreturn-to-zero on-off keying (NRZ-OOK) modulation of a commercial phosphorescent white light LED. The 3-dB modulation bandwidth of such devices is only a few megahertz. We proposed an analog pre-emphasis circuit based on NPN transistors and an active post-equalization circuit based on an amplifier to enhance the 3-dB bandwidth of VLC link. Utilizing our proposed pre-emphasis and post-equalization circuits, the 3-dB bandwidth of VLC link could be extended from 3 to 233 MHz with blue-filter, to the best of our knowledge, which is the highest ever achieved in VLC systems reported. The achieved data rate was 550 Mbit/s at the distance of 60 cm and the resultant bit-error-ratio (BER) was 2.6 × 10⁻⁹. When the VLC link operated at 160 cm, the data rate was 480 Mbit/s with 2.3 × 10⁻⁷ of BER. Our proposed VLC system is a good solution for high-speed low-complexity application.

Quantum dot white light-emitting diodes (QD-WLEDs) were fabricated from green- and red-emitting AgInS₂/ZnS core/shell QDs coated on GaN LEDs. Their electroluminescence (EL) spectra were measured at different currents, ranging from 50 mA to 400 mA, and showed good color stability. The modulation bandwidth of previously prepared QD-WLEDs was confirmed to be much wider than that of YAG:Ce phosphor-based WLEDs. These results indicate that the AgInS₂/ZnS core/shell QDs are good color-converting materials for WLEDs and they are capable in visible light communication (VLC).

This article describes an analog modulator that contains modulation, a MOSFET drive, and pre-emphasis circuits for a high-speed VLC application system based on a commercial phosphorescent white LED. We propose a small signal modulation model that is implemented by an AC-coupled N-channel MOSFET circuit and present a pre-emphasis circuit to enhance the 3 dB bandwidth of a VLC link. Utilizing our proposed analog modulator combined with blue filtering, the 3 dB bandwidth of a VLC system could be extended from 3 to 175 MHz, which allows OOK-NRZ data transmission up to 460 Mb/s with BER below 10-9 under a 1 m radial distance. With a simple analog modulator based on the simplest OOK-NRZ modulation scheme, a high-speed VLC system could be realized. The VLC link with the proposed analog modulator is a good solution for a high-speed low-complexity and low-cost practical VLC application system.

We present a high-speed visible light communication (VLC) link that uses a commercially available phosphorescent white light-emitting diode (LED). Such devices have few megahertz bandwidth due to the slow response of phosphorescent component, which severely limit the transmission data rate of VLC system. We propose a simple pre-emphasis circuit. With blue-filtering and the pre-emphasis circuit, the bandwidth of VLC system can be enhanced from 3 to 77.6 MHz, which allows non-return-to-zero on-off-keying (NRZ–OOK) data transmission up to 200 Mb/s with the bit error ratio of 5.3 × 10-7 which is below 10-6. The VLC link operates at the room illumination level of ~1000 lx at 1.1 m range using a single 1 W white LED.

The monolithically integrated self-driven photoelectric detector (PD) with the light-emitting diode (LED) epitaxial structure completely relies on the built-in electric field in the multi-quantum wells region to separate the photogenerated carriers. Here, we propose a novel superlattices–electron barrier layer structure to expand the potential field region and enhance the detection capability of the integrated PD. The PD exhibits a record-breaking photo-to-dark current ratio of 5.14 × 107, responsivity of 110.3 A/W, and specific detectivity of 2.2 × 1013 Jones at 0 V bias, respectively. A clear open-eyed diagram of the monolithically integrated chip, including the PD, LED, and waveguide, is realized under a high-speed communication rate of 150 Mbps. The obtained transient response (rise/decay) time of 2.16/2.28 ns also illustrates the outstanding transient response capability of the integrated chip. The on-chip optical communication system is built to achieve the practical video signals transmission application, which is a formidable contender for the core module of future large-scale photonic integrated circuits.