Making the case for WDM-PON

by Meghan Fuller Hanna

To date, the majority of WDM-PON deployment has been in Korea, with Korea Telecom connecting about 150,000 subscribers, but even KT is said to be scaling back its investment in the technology. WDM-PON's detractors say the technology is simply cost-prohibitive in the near term.

But for every detractor, WDM-PON also seems to have a champion, and those champions have become more vocal. Among them is LG Nortel (www.lg-nortel.com), a joint venture of Korea's LG Electronics and Nortel that recently spent $16 million (plus an additional $10 million if certain business targets are met during the next 18 months) to acquire arguably the industry's best-known WDM-PON vendor, Novera Optics (www.noveraoptics.com).

The decision to acquire Novera Optics was carefully weighed, recalls Giovanni Manto, leader of Nortel's Ethernet Fiber Access Solutions division. (For the record, Manto says LG Nortel itself has been working on WDM-PON "for at least five or six years now.")

While he admits that WDM-PON technology is still "in its infancy," Manto says LG Nortel is bullish on the technology. In fact, he says, the company believes WDM-PON can be cost competitive, in volume, with other next-gen technologies, such as the 10-Gbit/sec version of GPON (NG PON) currently under development in the ITU's FSAN committee.

Of course, some will argue that the Novera acquisition gives Nortel a much-needed foothold in the access market, which the vendor exited during the bubble years. Wrote Ovum (www.ovum.com) VP Lynn Hutcheson in a recent comment, "At best, [the acquisition] will provide a few bragging rights for Nortel as it will be the only broadband access player with a WDM-PON product, but that is all, as the market for this product is still a few years away."

For its part, Nortel maintains that, however rudimentary, the technology exists today, it works, and it may not be as far out as some people think.

"What WDM-PON does for you, it actually builds a foundational infrastructure," explains Manto. "Once you fix the couplers in the network, once you fix the fiber routing, then you have a ubiquitous network that could offer services from 10 Mbits/sec all the way up to a gigabit per user and eventually 10 gigabits in the future as the technology matures in a point-to-point fashion."

"And this is without going outside in the outside plant and reconfiguring couplers and fibers and splitters," he continues. "Once it's in the ground, it stays in the ground. Hence, it brings to you a foundational infrastructure that is deterministic and symmetrical."

And that message, he says, is resonating with the carriers LG Nortel has consulted recently. "To date, the only game in town is point-to-point where you have a single or dual fiber going to the business or residence or a point-to-multipoint solution, such as GPON or variants of PON that have surfaced in the latter years. Now," he adds, "there is an alternative: WDM-PON."

When asked to characterize interest in WDM-PON from a geographical perspective, Manto says the North American marketplace is currently dominated by "a 900-lb gorilla called Verizon" and its GPON deployment. And in Asia, EPON has established a substantial beachhead, particularly in Japan. But in Europe, he says, there are two kinds of customers. "One is basically saying, �We want to build point-to-point networks. We believe point-to-point networks are scalable networks; they are foundational; and we can change the personality of that particular fiber connection depending on what our customers want,' " says Manto. "And some of them have stipulated publicly that GPON will never be deployed in their network. Then there are other customers in Europe that are looking at GPON, but they are re-evaluating their decisions [because] now there's another solution in town."

Recent announcements from the European Union that it is funding two three-year WDM-PON initiatives speaks to the region's level of interest in the technology. Through its Information and Communications Technologies (ICT) program, the EU is investing �3 million (US$4.4M) in the Gigabit Access Passive Optical Network using Wavelength Division Multiplexing (GigaWaM) project and another �2.61 million (US$3.9M) in the Scalable Advanced Ring-based passive Dense Access Network Architecture (SARDANA) project.

Participants in the GigaWaM project include Ericsson (www.ericsson.com), Ignis Photonyx (www.ignis.com), Vertilas (www.verti las.com), and Syntune (www.syntune.com). Tasked with developing application-specific optical components for a WDM-PON subsystem, the project will be led from Ignis Photonyx's Birkeröd, Denmark-based PLC fab.

The SARDANA initiative, meanwhile, aims to increase the capacity and reach of FTTH networks through a combination of WDM-PON and remote amplification technology. Participants include research institutions in Greece, Portugal, and Italy, as well as Tellabs (www.tellabs.com). The project has a Tier-1 champion in France Telecom, which is expected to test the resultant architecture in a field trial in Lannion, France, in 2010.

In a research note dated August 4, 2008, analysts at Telecom Strategy Partners (www.telecomstrategypart ners.com) argue that WDM-PON "could give vendors with strengths in optics but less strength in broadband access a potential way to gain a foothold in this market in the not too distant future. So WDM-PON at least holds the potential future promise to help shake up the competitive playing field for operators and vendors alike."

That certainly seems to be the case. In addition to those vendors working under the auspices of the EU's ICT program, others are also starting to make some noise around WDM-PON, among them ADVA Optical Networking (www.advaoptical.com). The company recently introduced its CWDM-PON capabilities. It has added packet transport functionality on its FSP 3000 platform and debuted a temperature-hardened, 16-channel CWDM-PON device that enables it to take 16 CWDM channels, available as client side interfaces from the FSP 3000, and connect those channels to an SFP 150 Ethernet access device.

"The key benefit that our customers are looking for is...the ability to do fiber relief," says Paul Morkel, ADVA's senior director of business management, carrier WDM. "For [a] link between the CO and [a] remote node, being able to use a single fiber instead of multiple fibers in this case would replace a total of 16 fibers with just one fiber." Morkel confirms that ADVA is seeing "quite a bit of customer demand from [its] carrier customers" for CWDM-PON.

Also confirming carrier interest in WDM-PON technology is ADC (www.adc.com), which last year inked a partnership with Novera. ADC recently confirmed to Lightwave that it is currently trialing its ADC-branded Pony Express WDM-PON system "all around the world." (At press time, there had been no official announcement about how the LG Nortel acquisition of Novera would affect ADC's partnership with the company, and LG Nortel spokespeople declined to comment.)

For his part, Nortel's Manto is not surprised by the increased interest in WDM-PON from both the carrier and vendor communities. "The technology itself is quite simple," he says. "People make a lot of WDM-PON being complex or expensive or far into the future, but the technology exists today. You have a number of component vendors that are industrializing the components. You're starting to see some significant momentum, and I think it's just a matter of time before it comes to fruition in the marketplace," he concludes.

Meghan Fuller Hanna is senior editor at Lightwave.

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