China Telecom, Yangtze Optical Fibre and Cable (YOFC), and Decolink have jointly completed the world's first field trial of a hollow-core fiber single-wavelength 1.2 Tb/s ultra-long single-span unrepeatered wavelength division multiplexing (WDM) transmission system. The trial achieved a transmission capacity of 51.3 Tb/s over a distance of 206.5 km, without using any signal regeneration equipment or remote pump amplifiers throughout the entire process.

This trial was conducted on a commercial hollow-core fiber cable route. The focus was not merely on setting new transmission speed records, but on verifying the long-distance, high-capacity transmission capabilities of hollow-core fiber in a real network environment. The project adopted an optimized scheme for single-wavelength rate and channel power, using only EDFA amplification to achieve 206.5 km single-span unrepeatered transmission, setting a new record for the capacity-distance product of single-span unrepeatered WDM transmission systems without remote pump amplifiers.

The technical characteristic of hollow-core fiber lies in the fact that optical signals primarily propagate through an air core. Compared to traditional solid-core fiber, this type of fiber helps reduce transmission latency and mitigate nonlinear effects, making it suitable for continued verification in high-bandwidth, low-latency network scenarios. International tech media reports also noted that this trial provides a new transmission technology paradigm to address the bottlenecks in data center interconnection and GPU cluster communication in the AI era.

For the communication equipment industry chain, the value of this trial extends beyond the fiber itself. High-speed coherent transmission equipment, optical modules, amplifiers, line monitoring systems, optical network control platforms, data center interconnection equipment, and engineering deployment capabilities will all be reassessed as hollow-core fiber enters the field verification phase. Decolink's participation in the trial also indicates that optical components and transmission systems need to be synchronously adapted to new types of fiber lines.

Currently, large-scale commercial deployment of hollow-core fiber still requires addressing issues related to cost, attenuation, connectors, splicing techniques, long-term reliability, and operation and maintenance standards. However, the field trial results of 206.5 km, 51.3 Tb/s, and no signal regeneration have moved hollow-core fiber from experimental verification to a stage closer to engineering deployment. Whether this technology can subsequently be applied in scenarios such as AI data center interconnection, metropolitan backbone networks, and cross-regional computing power scheduling will remain a key focus for the optical communication industry.