7.4-Gbit/s Visible-Light Communication Utilizing Wavelength-Selective Semipolar Micro-Photodetector

Abstract

Visible light communication (VLC) has drawn significant attention in recent years. Though high-speed visiblelight sources have seen significant advances, commercially available photodetectors have low wavelength selectivity and modulation bandwidth in the near-violet-blue wavelengths, making them a bottleneck in VLC links. Here we show a record 7.4-Gbit/s visible-light communication link using a wavelengthselective, (2021)-oriented, semipolar InGaN/GaN multiplequantum- well micro-photodetector (μPD) on a GaN substrate. This is achieved by leveraging on the unique photodetection properties of semipolar μPDs, combined with an optimized communication system utilizing bit- and power-loading schemes in orthogonal frequency-division multiplexing (OFDM) modulation over a 2-GHz bandwidth. We used a 405-nm violet laser diode transmitter as the responsivity of the μPD was highest within the responsivity range from 360 to 420 nm. The investigation fully demonstrated the feasibility and favorable choice of semipolar InGaN/GaN μPDs for multi-Gbit/s optical wireless communication.