Terahertz topological photonics for on-chip communication

Robust terahertz wave transport is demonstrated on a silicon chip using the valley Hall topological phase. Error-free communication is achieved at a data rate of 11 Gbit s(-1), enabling real-time transmission of uncompressed 4K high-definition video. The realization of integrated, low-cost and efficient solutions for high-speed, on-chip communication requires terahertz-frequency waveguides and has great potential for information and communication technologies, including sixth-generation (6G) wireless communication, terahertz integrated circuits, and interconnects for intrachip and interchip communication. However, conventional approaches to terahertz waveguiding suffer from sensitivity to defects and sharp bends. Here, building on the topological phase of light, we experimentally demonstrate robust terahertz topological valley transport through several sharp bends on the all-silicon chip. The valley kink states are excellent information carriers owing to their robustness, single-mode propagation and linear dispersion. By leveraging such states, we demonstrate error-free communication through a highly twisted domain wall at an unprecedented data transfer rate (exceeding ten gigabits per second) that enables real-time transmission of uncompressed 4K high-definition video (that is, with a horizontal display resolution of approximately 4,000 pixels). Terahertz communication with topological devices opens a route towards terabit-per-second datalinks that could enable artificial intelligence and cloud-based technologies, including autonomous driving, healthcare, precision manufacturing and holographic communication.