A high-fiber network: Corning, Lucent compete with similar high-capacity fiber solutions

Bandwidth is king. Nothing pleases carriers more than handling large amounts of traffic on the network.

If you can increase capacity in fiber, you can increase network traffic. That's how Corning Inc. and Lucent Technologies approach new fiber technologies.

Lucent's TrueWave Reduced Slope is tailored for long-distance applications with high bit-rate transmission requirements. AllWave is Lucent's solution for metro applications such as interoffice communications, cable TV and fiber to the home or business.

Corning offers the SMF-28 and Titan single-mode fibers for metro and local access networks. Its LEAF fiber is designed for longer distances.

The fiber industry is regaining importance, said Pat Emery, manager of fiber optic applications at Lucent. "We're moving from an era where one single-mode fiber fits all applications to an era where a variety of fiber is tailored for specific applications," he said.

Fiber designs consider three issues: the effective area (the cross section through which the light passes), the dispersion slope (signal distortion) and the microbending loss (the amount of light that escapes the fiber when bent).

The tradeoff with fiber comes from effective area and dispersion, Emery says. Corning's LEAF competes with Lucent's TrueWave RS in this space (see figure). LEAF has more power and a larger effective area, says Curt Weinstein, manager of high data rate applications at Corning. TrueWave RS has less dispersion slope.

"The effective area of all nonlinear fiber is proportional to the amount of power in the fiber," Weinstein explained. "Higher data rates need an increasingly larger amount of optical power to deliver high-bandwidth channels. If you multiplex many wavelengths on a single fiber and aggregate that amount of power, it's a catalyst for nonlinear effects to occur. The objective in fiber designs is to minimize the nonlinear thresholds so they don't impair your system."

Corning's LEAF fiber has the same bend and splice characteristics of existing fiber. It's similar to TrueWave, "but we can put 2 dB more power into the fiber," Weinstein said. The additional power means the signal travels farther before it needs to be amplified.

Emery calls the tradeoff "the conservation of agony. If you want a larger effective area, you pay for it in some fashion. You have higher dispersion." Lucent thought it was better in terrestrial systems to have a low dispersion slope, he said. "A fiber with a lower effective area is less sensitive to microbending loss."

Pushing fiber advances is dense WDM, says Mathew Steinberg, director of optical networking at Ryan Hankin Kent. The advances are "evolutionary but significant," and all target WDM, he said. Carriers are mining the bandwidth out of fiber, and vendors are determined to expand the number of channels supported within the fiber.

More changes are ahead, Weinstein predicted. "Things are dynamic. Where fiber was sleepy, things are starting to happen."

WORLDPORT TO GROW GLOBAL NET International service provider WorldPort Communications has signed a $30 million agreement with Northern Telecom to expand its global network. WorldPort will deploy Nortel's DMS-Global Services Platform switching systems in New York, Miami, London and Copenhagen, Denmark. Nortel is also providing value-added services.

A BROADER MARKET The broadband market is expected to blossom in the next five years. According to The Strategis Group's study on global broadband markets, the number of businesses using broadband services will triple by 2003, and customers will spend about $800 a month for the service. The number of households with broadband services will increase ninefold, and consumers will pay about $35 a month for access.