20 Dec Bringing Legacy Fiber Optic Cables Up to Speed
Installing optical fibers with fat cores once seemed like a good idea for local-area or campus data networks. It was easier to couple light into such “multimode” fibers than into the tiny cores of high-capacity “singlemode” fibers used for long-haul networks.
The fatter the core, the slower data flows through the fiber, but fiber with 50-micrometer (µm) cores can carry data at rates of 100 megabits per second up to a few hundred meters—good enough for local transmission.
Now Cailabs in Rennes, France has developed special optics that it says can send signals at rates of 10 gigabits per second (Gbps) up to 10 kilometers through the same fiber, avoiding the need to replace legacy multimode fiber. They hope to reach rates of 100 Gbps, which are now widely required for large data centers.