Scientists build a four-lane highway for light inside a single photonic chip

Researchers in China built a topological photonic chip that uses nearly the entire surface for four parallel light channels.

A honeycomb magnetic-rod structure splits electromagnetic waves into valley states, and four cyclic variants guide one signal each while blocking reverse waves from neighboring regions.

In microwave tests, signals traveled around sharp bends and defects with little backscatter, demonstrating dense, edge-free robust light transport.

The design could enable smaller, denser, and more efficient photonic circuits for communications, quantum technologies, and optical computing.