[News] YOFC Achieved World’s First 1.2Tb/s Per-Wavelength Transmission Over Hollow-Core Fiber
On June 16, Yangtze Optical Fibre and Cable Joint Stock Limited Company (YOFC) announced the successful completion of the world’s first field-trial hollow-core fiber (HCF) wavelength-division multiplexing (WDM) transmission system capable of delivering 1.2Tb/s per wavelength over an ultra-long unrepeatered span. The trial was jointly conducted by China Telecom, YOFC, and Dekoli, under the framework of the National Key Laboratory for Advanced Manufacturing and Application Technologies of Optical Fibers and Cables.
The demonstration was carried out on the world’s longest cross-border commercial hollow-core fiber cable. Leveraging a self-developed optimization scheme for per-wavelength transmission rates and channel power allocation, the team achieved 51.3Tb/s transmission over a single 206.5-km unrepeatered span using only erbium-doped fiber amplifier (EDFA) amplification. The result set a new world record for the capacity-distance product of unrepeatered WDM transmission systems without the use of remote-pumped amplifiers.
Hollow-core fiber employs a fundamentally different light-guiding mechanism, transmitting optical signals through air rather than glass. By overcoming the capacity and latency limitations inherent to conventional solid-core fibers, HCF is widely regarded as a key enabling technology for next-generation optical communications, particularly in backbone and data-center networks.
Supported by China Telecom’s Cloud-Network Convergence Pilot Platform—an intermediate-scale testing facility approved by China’s State-owned Assets Supervision and Administration Commission—and the National Key Laboratory for Advanced Manufacturing and Application Technologies of Optical Fibers and Cables, the project team successfully addressed the challenge of high-power transmission in a live-network HCF environment for the first time, validating the technology’s high-speed transmission capabilities.
At the system level, the researchers developed an adaptive per-wavelength rate control scheme combined with flexible channel power allocation. The approach enabled hybrid transmission across multiple data rates, channel spacings, and per-wavelength power levels, mitigating capacity degradation caused by gas absorption peaks and unlocking more of the transmission potential of hollow-core fiber.
On the equipment side, the team adopted a cascaded dual-gain-unit high-power amplification architecture and a multi-element doping design to develop a high-power amplifier featuring excellent gain flatness and an output power of up to 33.5 dBm. Additional safeguards—including optical-path power anomaly detection, interlock shutdown functions, and alarm-linkage mechanisms—were introduced to minimize safety risks associated with optical link failures.
(Photo credit: YOFC)
