The Lightwave Blog

By Meghan Fuller Hanna

Last week, Infonetics Research released its latest PON market forecast, which included, for the first time, a quantifiable analysis of WDM-PON. The market research firm believes annual port shipments for WDM-PON will grow at a 41% CAGR between 2007 and 2011.

Neither the 41% CAGR nor the fact that Infonetics has included an actual forecast of the WDM-PON market surprises me. I would characterize WDM-PON as the sleeper trend of last month's OFC conference. Representatives from no less than a half dozen Tier-1system vendors confirmed to me that they are exploring the technology.

Here are some random tidbits I've been able to glean thus far:

* Some believe WDM-PON has a solid business case now relative to GPON, but the sticking point, as you might imagine, appears to be the cost. System vendors will lean heavily on the component suppliers (like they aren't under enough pressure already) to get the price reductions required before widespread deployment is economically feasible.

* When we think of WDM-PON, we tend to think of it in terms of residential service delivery, but early deployments will likely deliver high-capacity business services and/or IPTV backhaul.

* There is a big difference between CWDM-PON and DWDM-PON. CWDM-PON would be less expensive and a far easier proposition; pluggable CWDM optics are available now. However, operators would be limited to a capacity of eight to 16 wavelengths. DWDM-PON, by contrast, could support upwards of 40 to 80 wavelengths and beyond, but it represents a much greater technical challenge. The AWGs, for example, must be athermal and environmentally hardened. And the cost of the optics is higher because of the narrower channel spacings.

At a macro-level, WDM-PON makes a lot of sense. We're already seeing the optical layer begin to migrate further and further into the access network (the emergence of edge ROADMs would be a key example), and some sort of access WDM would seem like a natural extension to this trend.