LAS VEGAS -- NXTcomm 2008 -- What do you do when you're having such a hard time gaining traction with GPON that you voluntarily give up your biggest customer? (See Tellabs Kills Its Verizon GPON Efforts.) Get a head start on the next big thing –- WDM-PON.

Tellabs Inc. (Nasdaq: TLAB; Frankfurt: BTLA) is planning to do just that, joining a three-year project for developing what promises to be the next big step in broadband access. (See Tellabs Preps for WDM-PON.)

Tellabs will spend that time working as part of a European commission of research firms, services providers including Orange (NYSE: FTE), and other vendors on what they're calling the Scalable Advance Ring-Based Passive Dense Access Network Architecture. Since you’ll never remember or want to repeat that ever again, the project also goes under the name Sardana.

Tellabs will help develop and conduct field trials of WDM-PON technology that will be 128 times faster out of the optical line terminal (OLT) than today’s GPON networks. It's just a test for now, meaning it's not certain the technology will get commercialized for mass production.

"We operate out of the assumption that bandwidth demand will continue to grow,” says Mark Cannata, Tellabs's director of marketing for access products. "We think you’re going to need to dedicate a wavelength per home."

In current PON architectures, the wavelength of light that comes out of the OLT is typically split among 32 different homes. With WDM-PON, it's possible to give each home its own wavelength, opening the possibility of sending customers 1 Gbit/s or more.

Tellabs will be testing ways of using narrower optical spacing to cram more wavelengths onto each fiber. "It requires all kinds of electronic and optical compensation techniques to make sure that the wavelengths don’t interfere with each other," Cannata says.

Most vendors agree WDM-PON looks like a long-term winner. But so far, it's too expensive for most carriers to consider.

Tellabs believes carriers are five years away from needing WDM-PON. But even though GPON has been moving slowly, Tellabs doesn't expect the same thing to happen with WDM-PON once it hits the market.

"A lot of my time is spent with customers trying to convince them just to move to PON in the first place," says Cannata. "It takes a big step to decide to make the capex investment to string fiber all the way to the premises. But once you’ve gotten past that first step of Layer 1 infrastructure, when things like WDM-PON come along you’ll be able to just modify electronics at both ends of the fiber connection and deliver a wavelength of light to each customer."

Tellabs says it wants to get an early head start on WDM-PON so it can be ready the moment carriers start demanding it. While its GPON experience with its biggest customer, Verizon Communications Inc. (NYSE: VZ), was not a successful one, Tellabs says it would certainly welcome having the telco back as an access customer with WDM-PON.

— Raymond McConville, Reporter, Light Reading