Riding the wave of fiber network construction around the world, Adtran announced that more than 100 service providers have now adopted its new Combo PON offering, including cable operators, telcos, fiber providers, wireless ISPs and several network operators receiving Rural Digital Opportunity Fund (RDOF) grants from the US government.

The roster of Combo PON adopters includes Armstrong, the 11th largest cable operator in the US. The MSO, which serves cable subscribers in six states (Kentucky, Maryland, New York, Ohio, Pennsylvania and West Virginia), has switched its emphasis to all-fiber networks, GPON and now XGS-PON technology rather than pursue further upgrades of its legacy DOCSIS technology.

"Over the past fifteen years, Armstrong has evolved toward a fiber-to-the-premise architecture to support many wavelengths of light on the same glass," said Mike Giobbi, CTO of Armstrong, in a written statement. "In collaboration with Adtran, Armstrong has deployed PON technology with GPON to deliver speeds over 2 Gbit/s downstream and 1.25 Gbit/s upstream. We are now overlaying XGS-PON technology with the capacity of symmetrical 10 Gbit/s downstream and upstream on the same fiber strand into homes and businesses with GPON."

In a series of press releases issued Wednesday morning, Adtran said that "almost every type of service provider" has now "embraced" its Combo PON technology as "the ideal way to scale 10G PON access services within both existing and greenfield networks." Besides Armstrong, the broadband access vendor identified three other US service providers that have signed up for Combo PON – namely, New Lisbon Broadband and Communications (NLBC) in Indiana, Pennsylvania Telephone Company (PTC) and Centre WISP in Pennsylvania, all three of them RDOC winners.

With the 100-plus Combo PON adopters representing about a 50/50 mix of new and existing customers, Adtran officials are optimistic that the flow of providers to the new fiber product will continue unabated. "We're really quite bullish we'll stay on the pace of adding 100 new [fiber] customers a year," said Kurt Raaflaub, head of product marketing for broadband access at Adtran.

Adtran's Combo PON offering, which competes against similar products from Nokia, Huawei and ZTE, works by allowing service providers to support both GPON and XGS-PON technologies simultaneously over a common optical distribution network (ODN). As a result, providers can upgrade their broadband subscribers to symmetrical 10 Gbit/s XGS-PON without disrupting service.

Adtran claims this leads to "overwhelming savings" for its fiber customers, slashing their capex by 50%, their power consumption by 66% and their space needs by 75%. The vendor also posits that Combo PON pumps up broadband service revenue, offers 25% more gigabit service coverage and boosts network asset lifespan by 25%.

"You don't need two pieces of equipment anymore and co-existence elements" to upgrade to 10G PON service, Raaflaub said. "Combo PON is a much greener technology by 50%."

Without providing specifics, Raaflaub argued that the cost of upgrading to Combo PON optics is not really greater than the cost of upgrading to either GPON or XGS-PON optics. "It really comes out to a wash," he said. Plus, he added, "it really opens up the 10G business case."

Industry analysts appear to agree with Adtran's assessment of its latest PON product.

"For many different types of service providers, from electric co-ops to rural ISPs, the value of scalable gigabit services and game-changing multigigabit services cannot be overstated," said Julie Kunstler, Senior Principal Analyst at Omdia (a sister company of Light Reading), in a written statement. "Combo PON technology provides a seamless network and capacity upgrade path as well as opportunities to expand addressable markets and revenue streams. Combo PON solutions provide service providers with flexibility regarding the use of next-gen PON for specific customers and applications; thereby increasing ROI over the same ODN."

What will be particularly interesting to see is how many other cable operators follow Armstrong's lead and switch to running next-gen versions of PON over new fiber networks rather than upgrade to DOCSIS 4.0 technology over their existing hybrid fiber-coax (HFC) networks. A number of operators have said they are wary of spending the large sums needed to upgrade their HFC networks to D4.0 when they could instead spend the money to go all-fiber.

— Alan Breznick, Cable/Video Practice Leader, Light Reading