  The computing speeds in modern multi-core processors and big data servers are
no longer limited by the on-chip transistor density that doubles every two
years following the Moores law, but are limited by the on-chip data
communication between memories and microprocessor cores. Realization of
integrated, low-cost, and efficient solutions for high speed, on-chip data
communications require terahertz (THz) interconnect waveguides with tremendous
significance in future THz technology including THz-wave integrated circuits
and THz communication. However, conventional approaches to THz waveguiding
suffer from sensitivity to defects and considerable bending losses at sharp
bends. Here, building on the recently-discovered topological phase of light, we
experimentally demonstrate robust THz topological valley transport on low-loss,
all-silicon chips. We show that the valley polarized topological kink states
exhibit unity transmission over a bulk band gap even after propagating through
ten sharp corners. Such states are excellent information carriers due to their
robustness, single-mode propagation, and linear dispersion-key properties for
next generation THz communications. By leveraging the unique properties of kink
states, we demonstrate error-free communication through a highly-twisted domain
wall at an unprecedented data rate (10 Gbit/s) and uncompressed 4K
high-definition video transmission. Our work provides the first experimental
demonstration of the topological phases of THz wave, which could certainly
inspire a plethora of research on different types of topological phases in two
and three dimensions.
