The Lightwave Blog

Posted by Stephen Hardy

The NCTA Cable Show in Washington, DC, this week inspired a few announcements targeting the use of FTTH technology by MSOs, based either on RFoG, PON (here and here), or both.

But while many have speculated that RFoG is merely a waypoint on the path to PONs, John Dalquist, vice president of marketing at Aurora Networks, says MSOs aren't exactly stampeding toward the use of PON for residential applications. Most of his customers that are thinking about serving homes with fiber are going the RFoG route, he says. PON, for the most part, is being reserved right now for the delivery of commercial services to businesses.

The exception is in Europe, where there's interest in what Dalquist called a "blast and split" approach that looks a lot like Verizon's combination of RF broadcast and IP services via PON.

Labels: MSOs, PON, RFoG

Posted by Stephen Hardy

As you'll see in an article that will appear in the November issue of Lightwave, the working group within SCTE that is shaping the RF over Glass (RFoG) standards has hit a stumbling block. The group has reached consensus on 1550 nm as the downstream wavelength. However, determining which upstream wavelengths to use has become an issue.

The problem is that the working group, which contains several equipment vendors that also make PON systems, is attempting to construct the specifications in such a way that carriers can overlay a PON over the RFoG infrastructure. Given the wavelengths already in play for GPON and EPON, plus those expected to be used for the 10-Gbit/sec standards now under development within FSAN and the IEEE, there aren't a lot of attractive wavelengths left. And if you can't leverage the volumes that lasers tuned to the already popular wavelengths enjoy, how can you keep costs down?

At the heart of the conundrum is the question of the role RFoG will play on the path toward all-optical MSO networks. One source for my article, whose company currently supplies RFoG-like equipment, asserts that the PON suppliers are pushing an agenda in which RFoG is merely an interim step toward PONs. The source disagrees with this philosophy; his feeling is that RFoG architectures will have a long life within MSO networks, and that the SCTE should therefore focus on what's the most cost-effective way to deploy them, PONs be damned.

Despite this hiccough, consensus indicates that the SCTE working group will complete its task by the middle of next year. But it would appear that carriers could play a very useful role by communicating their viewpoints on the expected relationship (or lack of it) between RFoG and PONs.

Labels: FTTH, MSOs, RFoG