Lumen to double size of US network with six million extra miles of fiber

Lumen Technologies Tuesday said it would double the size of its US intercity network to 12 million fiber miles by the end of 2026. When complete, the telco says the network will connect 50 major cities across the United States at data rates of up to 400Gbps.

According to Lumen — formerly CenturyLink — the expansion will serve both the company’s internal services and fiber, which the telco sells to enterprise and government customers for use in their private networks. For instance, a customer might lease fiber from Lumen to connect its datacenter to a cloud service provider or colocation facility in a neighboring state or city.

Lumen has steadily added capacity to its US and European networks over the past few years, helped in no small part by the acquisition of Level 3 Communications in 2017. By taking advantage of the multiple access conduits laid more than 20 years ago when the network was initially built, Lumen says it can string additional fibers as capacity demands in a region ramp up and upgrade aging or damaged fiber.

“It’s difficult to upgrade legacy intercity networks without multiple conduits,” Lumen CTO Andrew Dugan said in a statement. Without them, “these networks end up being stuck with old fiber technology.”

As for the actual fiber filling these conduits, Lumen says it’s continuing to upgrade its intercity network with Corning’s SMF-28 ultra-low loss (ULL) and SMF-28 Ultra fibers.

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While Lumen touts the cables as supporting line rates up to 400Gbps today, SMF-28 isn’t exactly new or special. In fact, SMF-28 single-mode fiber is used in telco networks around the world and is seen by many as the industry standard.

It’s also worth noting that more recent refinements of SMF-28, including Corning’s ULL cables, can already support optics operating at well in excess of 400Gbps. We’ve already seen several optical vendors, including Infinera, demonstrate 800Gbps coherent optics across SMF-28. However, those optics are largely aimed at telco-line systems as opposed to the kinds of equipment that might be used in enterprise or government wide-area networks.

The expansion comes a little over a year after Lumen announced several new fiber routes across its European network. These included a 180-mile span from Lyon, France to Geneva, Switzerland, a 170-mile segment in Spain that connected Salou to the French border, and a new metro network in Barcelona connected to the MAREA trans-Atlantic cable in Sopelana. The upgrades brought the Lumen’s European fiber footprint to more than 23,600 miles. ®