DECEMBER 5, 2008 By Meghan Fuller Hanna -- In his keynote address during Lightwave's Optical Access '08 virtual conference and tradeshow, held yesterday, Vincent O'Byrne, director of FTTP architecture and design within Verizon's (search for Verizon) Technology Organization, confirmed that the carrier will be offering 100-Mbit/sec service next year. He also offered Verizon's perspective on several next-generation access technologies currently under development.
Today, Verizon offers its FiOS services in 16 states and is adding subscribers at a rate of 225,000 per quarter. The carrier is on track to pass 12 million homes by the end of the year. According to O'Byrne, Verizon currently sells service tiers with downstream speeds of 5, 10, 15, 30, and 50 Mbits/sec with up to 20-Mbit/sec upstream. He also confirmed that Verizon has conducted 100-Mbit/sec trials with a number of participants, and he expects that service "will be coming next year."
For his part, O'Byrne said he is bullish on the viability of Verizon's FiOS network over the long haul. The carrier's BPON systems support 100 Mbits/sec, while its GPON systems support "obviously a lot more than that," as he noted. But in light of new research in areas like next-generation HDTV and even 3D TV--both of which may require greater than 100 Mbits/sec to each customer--O'Byrne believes it's not too early to consider what's next.
"We have a network that is based purely on fiber," he reiterated. "It can support much more bandwidth than we need, and our BPONs and GPONs are providing, obviously, the services that the customer needs. But we want to make sure that � we are looking at what's coming next, how we should possibly transition, [and address] some of our concerns with the technologies being proposed."
O'Byrne stressed that neither the NGPON1 nor NGPON2 standards currently under discussion today are likely to be standardized until late 2010 at the earliest. NGPON1 can be broken into two phases, XGPON1 and XGPON2, and he argued that at least one aspect of XGPON1, which will provide 10G downstream x 2.5G upstream, is attractive to Verizon.
"One of the items that is important for us, given that we have deployed GPON already, is the requirement that it be able to coexist with GPON on the same fiber," he explained. "It may be that initially we would not deploy it on the same fiber. But in a lot of our deployment cases, if we can support it via some of our IT systems, it will actually reduce costs if we can do it on the same fiber, especially at low take rates," he said.
Only where the carrier has very high take rates on GPON and there isn't a lot of spare capacity will it be cost effective to run a separate NGPON, he said. "Every time we add a new PON, have to light up all 32 splits with an EDFA, and that increases our cost considerably," he reported.
XGPON2 would support 10G x 10G, though, as O'Byrne explained, the industry has not yet reached a consensus on whether a symmetrical offering is really needed.
Also on the table are proposals from both Alcatel-Lucent and Motorola to implement a stacked GPON architecture that would preserve the carrier's investment in its embedded base of ONTs.
As for NGPON2, which includes the possible development of WDM-PON, O'Byrne confirmed that Verizon has looked at some of the WDM-PON systems commercially available today, but said the carrier still has some reservations about the technology. First, he wondered whether arrayed waveguide gratings (AWGs) deployed in the outside plant would have to be temperature controlled. "Again, part of our philosophy is to have everything passive in the outside plant," he maintained.
And, secondly, he noted that WDM-PON does not currently support RF overlay, which "is key for us at present," he said, "as we don't have any plans to remove that."
O'Byrne concluded his keynote address with a discussion of the attributes Verizon would be looking for in a next-generation ONT:
• Smaller, more aesthetically pleasing;
• More power-efficient;
• The ability to support higher dynamic ranges;
• Lower 1550-nm receiver sensitivity;
• Increased reliability and out-of-the-box performance; and
• The ability to self-diagnose issues and self-police.
On the OLT side, he said, Verizon would like to see the following attributes:
• Non-blocking PON cards and support of full downstream rates;
• The ability to handle possible OSP reflectances when using a 2x2 splitter;
• Support for 1 x 64 optical splitting;
• Increased power efficiency to reduce footprint; and
• Higher reliability, as next-generation OLTs will support more business traffic and an overall over increase in traffic loads.
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