SPOTLIGHT: Innovation of the Week: WDM-PON

(Editor's Note: This is our first entry in a weekly series highlighting new technology innovations worth watching by public network operators and service providers. In the near future, we'll add our own detail reports of these innovations to the mix online at FierceTelecom.)

Passive optical networking technology, which allows multiple residences or neighborhoods to efficiently share fiber bandwidth, has become the architecture of choice for fiber-based access networks being deployed by telcos. To date, those efforts have focused mostly on broadband PON (BPON), gigabit PON (GPON) or other variations. BPON is capable of deliver about 622 Mbps from the telco central office to customer premises equipment, and the GPON standard boosts that figure to about 2.4 Gbps.

However, as telcos contemplate the opportunity to deliver all kinds of new video services and other applications to residential consumers, that kind of bandwidth, though impressive new, may come to seem inadequate. As a result, many telcos, at least at the lab level, are looking for the next step in the PON evolution.

It could involve a technology they are accustomed to seeing more in long-haul applications than in the access realm. Marrying wavelength division multiplexing to PON (WDM-PON) to create data rates potentially many times greater than even GPON may sound extreme. But, being able to deliver a full wavelength to every customer already might be the unstated goal of many telcos.

The advantages lie not only in the overall bandwidth, but also in the ability of some WDM-PON systems to create virtual point-to-point connections by using an arrayed wavelength grating at the neighborhood node to divide and distribute single fibers to each home. This improves security and reliability.

Korea Telecom, which has to meet government-sanctioned broadband goals, has been the most prominent carrier user of WDM-PON thus far, but NTT in Japan, Telecom Italia, BT, Verizon, Fastweb and others are all at various stages of evaluating WDM-PON.

The risk of deploying now is that availability of WDM-PON systems is still limited to a small number of vendors, with Fujitsu, Nortel Networks, Ignis Photonyx and Novera Optics among some of the notable suppliers. The technology is still maturing, too, which means patience may be rewarded with lower cost to deploy.

Even if telcos find they aren't ready for WDM-PON in the access network, it could still makes sense as a tool for backhauling all that broadband traffic to come.

For more information about WDM-PON, check out these stories from Telephony and Light Reading.