Going long

Fujitsu optical system expected to extend life, performance of WorldCom's fiber

Advances in fiber continually allow network builders to transmit more information for less money, but replacing fiber typically is cost-prohibitive for most carriers. By providing a cost-effective solution that allows legacy fiber to perform at terabit rates, Fujitsu Network Communications expects to make its first significant impact in the long-haul market via a contract with WorldCom.

Known as Flashwave OADX, the Fujitsu dense wave division multiplexing system is being tested as part of WorldCom's "Terabit Challenge," an open tryout of optical technologies proposed by vendors to increase capacity on the interexchange carrier's (IXC's) network.

"WorldCom is experiencing an increase in bandwidth demand; that's what's driving this objective," said Tim Novak, Fujitsu's business development manager for the WorldCom account team. "They want to increase their capacity by five- or six-fold, but they don't want to have a five- or six-fold increase in cost."

WorldCom's network currently can carry 320 Gb/s, but the carrier plans to increase its network capacity dramatically in the next few years. The Flashwave OADX delivers 1.76 terabits of information per second in tests conducted on 220 miles of existing WorldCom fiber extending from the Baltimore area to a city outside Newark, N.J.

"The Flashwave OADX is not only 1.76 terabits capable, we're actually filling [the network] up with 1.76 terabits of traffic," Novak said. "We're basically testing it to its fullest capacity."

Test traffic is carried over 176 channels, with each channel delivering 10 Gb/s for 400 kilometers without regeneration on any type of single-mode fiber. In both the C Band and the L Band, 88 channels are used with a spacing of 50 GHz between channels. In the next year, Fujitsu's system will support 40 Gb/s, although such an upgrade will require channel spacing to increase to 100 GHz, said Ray Moyer, Fujitsu's senior marketing manager for optical products.

"With Fujitsu, you're getting the maximum number of wavelengths and the maximum PDM rate per wavelength, and that adds up to the maximum capacity," said Bill Erickson, vice president of product planning for Fujitsu.

In addition to pure capacity, the Flashwave OADX is designed to give carriers greater flexibility, Moyer said. "They're not locked into one speed," he said. "Just change the components, and they can hit all the points in between."

Also benefiting carriers is the fact that the system requires less maintenance, Erickson said. Current 320 Gb/s systems require an expensive laser transmitter for each of the 32 channels. The Fujitsu system allows each laser transmitter to handle four channels, meaning 44 transmitters are needed - a notable alternative to the 176 transmitters that would be needed to provide the capacity using currently deployed architecture.

"That helps all the way around," Erickson said. "[Laser transmitters] are not an inexpensive part of the system."

In the next year, Fujitsu plans to have 22 channels handled by each transmitter, meaning only eight transmitters will be needed - a help to carriers' maintenance crews and the replacement inventory needs of Fujitsu and its customers, Erickson said.

Only Fujitsu and another undisclosed vendor reached the testing stage of the Terabit Challenge, said a WorldCom spokeswoman. "It was basically an open challenge, and these are the only two that met the challenge," she said.

WorldCom plans to begin moving to terabit solutions in its networks before the end of the year, the spokeswoman said. Though the Terabit Challenge technically is a test phase, all indications are that Fujitsu's participation will lead to a potentially lucrative contract with WorldCom. "While a decision has not been made, it would be unusual for us to only go with one vendor," the WorldCom spokeswoman said.

Inking a deal with WorldCom would be a coup for Fujitsu, said Dana Cooperson, director of optical transport for RHK. "It's a big deal because Fujitsu's market strength in North America has always been in the local market," Cooperson said. "[Long-haul transport] really is a new market area for them."

While Fujitsu is far from being on the level of long-haul equipment powerhouses such as Nortel Networks, currently WorldCom's primary vendor, a WorldCom deal would legitimize its efforts in the space, Martin said.

And the long-haul market offers plenty of opportunity for growth - particularly in the realm of upgrading the capacity of existing networks, which saves carriers the precious time and money that would be needed to bury new fiber, Cooperson said.