Abstract
Visible light communication (VLC) has drawn significant attention in recent years. Though high-speed visible-light 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 wavelength-selective, (2021)-oriented, semipolar InGaN/GaN multiple-quantum-well micro-photodetector (μPD) on 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 of 360 - 420 nm. The investigation fully demonstrated the feasibility and favorable choice of semipolar InGaN/GaN μPDs for multi-Gbit/s optical wireless communication.
Highlights
W ITH the increasing demand for high-speed wireless communication, the integration of optical wirelessManuscript received April 15, 2020; revised May 12, 2020; accepted May 13, 2020
Compositionally tunable InGaN/GaN multiple quantum-well (MQW) PDs can be tailored for visible-wavelengthselective applications which is imperative in light-fidelity (Li-Fi) applications and in underwater wireless optical communication (UWOC), due to its low attenuation in water [11]–[13]
We previously showed a 3.2 Gbit/s link using InGaN/GaN c-plane MQW PD by 16-quadrature amplitude modulation (16-QAM) with orthogonal frequency-division multiplexing (OFDM) [18], despite a limited modulation bandwidth (71.5 MHz)
Summary
W ITH the increasing demand for high-speed wireless communication, the integration of optical wireless. Compositionally tunable InGaN/GaN MQW PDs can be tailored for visible-wavelengthselective applications which is imperative in light-fidelity (Li-Fi) applications and in UWOC, due to its low attenuation in water [11]–[13] Their full potential in meeting the demand for towards-10-Gbit/s high-speed wireless communication is lacking [14]. This was enabled by the broader bandwidth provided by the semipolar orientation and the increased signal-to-noise ratio (SNR) offered by the high wavelength selectivity of the InGaN/GaN μPD with a responsivity of 0.11 A/W at 400 nm, −8 V. Compared to the previous OFDM data rate of ∼3 Gbit/s, the significantly higher data rate fully demonstrated, for the first time, the true potential of InGaN/GaN μPDs in ultrahigh-speed VLC and UWOC links closing towards 10-Gbit/s, by leveraging on semipolar PD
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