Comcast claims to be the first U.S. operator to trial air-core fiber technology with an eye toward latency and speed enhancements that could enable new use cases and support its rollout of 10G capabilities.
Comcast Cable's senior vice president of next-generation access networks said, "When you look at the opportunity for terrestrial distribution and the opportunity for continued innovation in delivery, I think this is a great example of what's going to happen next."
Hollow fiber cross-section
As the name implies, hollow-core fiber optic cables have a central channel filled with air and surrounded by a ring of glass filaments, so the cross-section looks much like a honeycomb with a cavity in the middle. The idea behind this arrangement is that light travels 50 percent faster in air than it does in glass, which means that this cabling can provide better performance and lower latency.
In a trial with air-core fiber supplier Lumenisity, Comcast deployed a 40-kilometer (nearly 25 miles) hybrid air-core and conventional fiber link on which it successfully tested both uplink and downlink transmission. It was able to simultaneously generate traffic rates of 10 Gbps to 400 Gbps on a single strand of hollow fiber. Operators were also able to demonstrate backward compatibility with hollow fiber.
So why are cable operators like Comcast interested in next-generation fiber? The technology has the potential to increase data transfer speeds by 150 percent and reduce latency by 33 percent, meaning it could have a significant impact whether deployed for core or access, the vice president noted.
"While our edge network is primarily coaxial, we still have a very large fiber network in the U.S., and having it as one of the options would certainly create some potentially very interesting use cases for us." He explained. This includes applications in a range of verticals, such as financial services, telemedicine, augmented and virtual reality, or any other latency-sensitive or data-intensive use cases.
While Comcast believes it is the first company in the U.S. to test hollow-core fiber, and that its 40-kilometer deployment is the longest to date, it is not the only company experimenting with the technology. British operator BT has revealed that it is testing hollow-core fiber in June 2021.
