High-speed underwater optical wireless communication using a blue GaN-based micro-LED

TLDR

The blue GaN micro‑LED emits at ~440 nm and experiences an underwater power attenuation of about 1 dB/m in tap water. The micro‑LED achieved 800 Mb/s at 0.6 m (BER 1.3×10⁻³), 100 Mb/s at –40 dBm (BER 1.9×10⁻³), and 200 Mb/s at 5.4 m with a BER of 3.0×10⁻⁶, while its modulation bandwidth saturated at ~160 MHz, proving high‑speed UOWC over several meters.

Abstract

High-speed underwater optical wireless communication (UOWC) was achieved using an 80 μm blue-emitting GaN-based micro-LED. The micro-LED has a peak emission wavelength of ~440 nm and an underwater power attenuation of 1 dB/m in tap water. The -3 dB electrical-to-optical modulation bandwidth of the packaged micro-LED increases with increasing current and saturates at ~160 MHz. At an underwater distance of 0.6 m, 800 Mb/s data rate was achieved with a bit error rate (BER) of 1.3 × 10-3, below the forward error correction (FEC) criteria. And we obtained 100 Mb/s data communication speed with a received light output power of -40 dBm and a BER of 1.9 × 10-3, suggesting that UOWC with extended distance can be achieved. Through reflecting the light emission beam by mirrors within a water tank, we experimentally demonstrated a 200 Mb/s data rate with a BER of 3.0 × 10-6 at an underwater distance of 5.4 m.