China activates world's first three-band optical fibre communication system

China activated the world’s first three-band optical fibre communication system early this month, technology that its developers say could expand the carrying capacity of future AI networks.

According to the project team, a single fibre can carry more than five times the traffic of conventional systems, while transmission capacity per core increases by nearly half.

The 35km (21.7-mile) link connects major computing facilities in the city and serves as a commercial test bed for next-generation optical networking technologies, according to a report by Shanghai Securities News on June 3.

The newly activated system simultaneously uses three transmission windows – the S-band, C-band and L-band – within a conventional optical fibre, allowing substantially more data to travel through existing infrastructure. In a China Mobile statement, the approach was compared to expanding “a two-lane motorway into a three-lane highway” without building an entirely new road.

Most long-haul fibre systems around the world rely mainly on the C-band and, increasingly, the L-band for commercial transmission, while technical challenges involving signal amplification, noise control and transmission stability have restricted the use of other parts of the optical spectrum.

The system works by combining two advances. It extends ultra-low-loss transmission capabilities into the S-band – a part of the light spectrum that was previously too unstable and noisy for regular commercial use – while combining them with multi-core fibre technology, according to the team.