Nortel unveils metropolitan optical portfolio

Nortel Networks Inc. unveiled a series of components intended to boost performance and decrease costs for metropolitan optical networks during a conference of fibre-optic engineers in Baltimore, Md., on Monday.

Nortel’s 14 components on display include:

– A 10G-bps (bits per second) APD preamp receiver – a component used to receive the laser pulse sent along fiber-optic lines before the laser light is amplified and retransmitted.

– A multi-wavelength gain module, featuring a compact amplifier and integrated variable optical attenuator. The module is a small box that equipment makers use to amplify data-carrying laser light and to even out the transmission strength of the data signal.

– Several 10G-bps Ethernet switch router products designed to replace networks built on the SONET (synchronous optical network) standard, in order to accommodate increasing data traffic demands by efficiently using dark, or unused, fiber-optic lines and DWDM (dense wavelength-division multiplexing) optical infrastructure.

Nortel did not disclose pricing on its equipment. Some products showcased, like a 2.5G-bps transmitter, are on the market now, while others are currently available for testing and will be widely available by early next year.

Nortel’s new components are aimed at network equipment makers and begin to address problems equipment makers have had developing products for metropolitan areas – that stripped-down components used in long-haul networks either cost too much or performed poorly, an analyst said.

“The metro stuff is not cost effective right now,” said Maribel Dolinov, a Forrester Research Inc. senior analyst. “It doesn’t perform as reliably as (manufacturers) want, it uses too much energy.”

The metro network offers an area of hope in the tough telecommunication equipment market. But metro networks require a technical approach different from cross-country networks.

“For long haul, you ideally want to transmit over thousands of miles,” said Parviz Tayebati, vice president of business development for Nortel. “One of the key issues is dispersion, you can’t have a lot of ‘chirp’,” or change in wavelength.

Another issue is that the best lasers used to transmit data in long-haul networks cost significantly more than lower-quality lasers that carry a couple hundred miles, he said.

One of the 14 products Nortel showcased is a 2.5G-bps buried heterostructure transmitter, which is a laser with a maximum reach of 175 kilometres before the dispersion of the laser light becomes so great that it must be amplified. It has some “chirp” compared to a long-haul laser, Tayebati said, but “you can’t just lower cost and give the same performance as long-haul without giving something away.”

Component manufacturers attempt to cut costs by retooling long-haul equipment in order to make it smaller. Often that results in components that use too much energy relative to their function, Dolinov said.

Nortel has heard the same from its users.

“The message we’re getting back is that it has to be lower cost and simpler, using less energy,” said Doug Alteen, a marketing vice president at Nortel.

Nortel’s credit-card sized 1310 nanometre 10G-bps transponder module uses about six watts of power. It combines the 2.5G-bps transmitter with a receiver and other components, saving design costs for equipment makers.

“We’ve learned a lot of things in the 10-gig long-haul area in terms of cost reduction, and one of these is automation,” Alteen said. Despite broad movement toward 10G bps speeds for equipment makers, and 40G bps on the horizon, 2.5G bps is “still a pretty important data rate in this space,” he said, reflecting cost concerns among network builders.

“Ten-gig is very hard to do at a cost-efficient rate,” for the metro area, he said.

Nortel, in Brampton, Ont., can be reached at