Chinese researchers have set a new world record for data transmission over hollow-core fiber, achieving 51.3 terabits per second across a single 206.5-kilometer (approximately 128-mile) unrepeatered span using only standard erbium-doped fiber amplifier (EDFA) amplification.
The trial was conducted by China Telecom, Yangtze Optical Fibre and Cable (YOFC), and Dekoli under a national research initiative focused on advanced optical fiber technologies. The demonstration ran on the world’s longest cross-border commercial hollow-core fiber cable.
Hollow-core fiber transmits optical signals through air rather than glass, overcoming both the capacity and latency limitations inherent to conventional solid-core fibers. At the system level, the team developed an adaptive per-wavelength rate control scheme combined with flexible channel power allocation, enabling hybrid transmission across multiple data rates, channel spacings, and power levels. This approach mitigated capacity degradation caused by gas absorption peaks in the hollow-core design.
On the equipment side, the researchers built a cascaded dual-gain-unit high-power amplifier with output power of up to 33.5 dBm, incorporating safeguards such as optical-path power anomaly detection and interlock shutdown functions.
The trial marks the first time high-power transmission in a live-network hollow-core fiber environment has been validated. The project was supported by China Telecom’s Cloud-Network Convergence Pilot Platform and the National Key Laboratory for Advanced Manufacturing and Application Technologies of Optical Fibers and Cables.
The record targets a specific bottleneck: the explosive growth in data center and AI traffic is straining conventional fiber infrastructure. Hollow-core fiber is widely regarded as a key enabling technology for next-generation optical communications in backbone and data center networks.