Toward Tb/s visible light communication: advances and integration of photonic devices

Visible light communication (VLC) has emerged as a prominent research direction in the context of beyond 5G (B5G) and 6G communications. The increasingly severe spectrum congestion in conventional radio frequency (RF) systems has driven both industrial and academic communities to explore higher-frequency bands, such as terahertz, infrared, and visible light spectra. Among these alternatives, VLC exhibits distinctive advantages, including 400 THz of valuable spectrum resources, eye safety, low electromagnetic leakage, favorable underwater transmission performance, and compatibility with existing illumination infrastructures. In recent years, numerous experimental VLC systems have been reported to support data rates exceeding 100 Gb/s, toward terabit-per-second (Tb/s) level transmission. Extensive studies have been conducted on key enabling technologies covering light sources, receivers, photonic devices, and multiplexing schemes, which lay the foundation for the implementation of ultra-high-speed VLC systems. However, VLC devices, especially on-chip photonic devices in visible light spectrum, lack sufficient studies and mature manufacturing process. This chronic issue afflicts VLC systems, hindering their performance from matching that of infrared-based communication systems and requiring arduous investigations in materials, devices, and systems. This paper accordingly reviews the corresponding technological innovations, vacancies of crucial technologies at the device level, and summarizes the development trends of state-of-the-art VLC systems, and proposes a systematic roadmap for VLC evolution in 6G communication networks.