Photonics and wireless converge at 512 Gbps
A team led by Peking University reported a converged optical-wireless communication system that carries 512 Gbps over fibre and 400 Gbps over the air from a single shared channel. The demonstration, reported on 20 February, is a small but concrete step toward the kind of network 6G will need.
On 20 February a team led by Peking University, with collaborators at the Peng Cheng Laboratory, ShanghaiTech University and the National Optoelectronics Innovation Center, reported a communication system designed for a world where fibre and wireless stop being separate networks. The system transmits data over a single shared optical channel and then delivers it two ways at once: 512 Gbps through an optical fibre and 400 Gbps over a wireless link, with the same stream feeding both. The numbers are laboratory records rather than field deployments, but they are a concrete demonstration of the architecture that next-generation networks are expected to run on.
The engineering problem the team addressed is a familiar one in disguise. The Internet’s backbone is optical: light in glass fibres carries data over continents, cheaply and at enormous capacity. The last mile is wireless: phones and laptops connect through radio, because glass cannot follow people around. Today those two domains meet awkwardly, at boxes that convert optical signals to radio and back, wasting capacity and adding latency. A converged system treats the optical and wireless links as one continuous channel, so that a data stream destined for a moving device stays in the same format from the data centre to the handset, and the optical bandwidth is shared rather than duplicated.
The paper’s result, 512 Gbps on fibre with 400 Gbps over the air from the same channel, is significant for the practical reason that the gap between the two rates is now small. A few years ago the mismatch was enormous, with wireless carrying a tiny fraction of what the fibre behind it could deliver. Closing that gap is precisely what makes converged transport useful: if the wireless tail can keep up with the optical trunk, then the trunk’s capacity stops being wasted at the edge, and a single unified network can allocate capacity flexibly between fixed and mobile users.
The demonstration sits in a longer trajectory toward the sixth generation of mobile networks. 6G, still in standardisation and expected to arrive commercially toward the end of the decade, has been described less by any single killer application than by a set of architectural promises: far higher data rates, much lower latency, and the integration of sensing and communication, all built on the assumption that the optical core and the radio edge become one system. Demonstrations like this one are how the pieces of that architecture get tested before the standards are locked, and how vendors and operators learn which of the many proposed ideas actually survive contact with physics.
As with every laboratory record, the distance from the bench to the base station is substantial. The system’s 400 Gbps wireless link works over short distances in a controlled environment, and translating it into a technology that copes with weather, interference and moving users will take years. What the result establishes is that the physics of a converged optical-wireless channel behaves as promised, that the shared architecture does not break at these speeds, and that the gap between the fibre and the air, once a yawning one, is now a bridge that engineers have actually begun to build.