Optical networking is the future, but copper is now

Optical networking is the future, but copper is now

ATLANTA'The SuperComm trade show this week highlighted optical networking products for the nation's current surplus of fiber-optic backbones, which carry photons rather than electrons.

'Nobody has put copper in the ground for years,' said Kelley Williams, marketing director for Lynx Photonic Networks Inc. of Calabasas Hills, Calif.

Copper cannot equal fiber's scalability and low maintenance, 'but it's there,' said David Perry, director of marketing for Actelis Networks Inc. The Fremont, Calif., company is developing a method to boost the efficiency of copper wiring. 'The appetite for bandwidth is inexhaustible. If copper can be leveraged, it will be used.'

The first version of the Optical Internetworking Forum's Network-to-Network Interface, which will facilitate optical connections between carrier networks, will likely be ready this year, said Steve Joiner, chairman of the OIF Technical Committee. The committee presented specifications for Version 1 of a User-to-Network Interface at SuperComm last year.

'Our intent is not to force forklift upgrades but to evolve,' Joiner said. 'There is no economic justification for forklift upgrades.' That means convergence of networks through optical interfaces could take decades rather than years, he said.

Meanwhile, Northrop Grumman Corp.'s Winchester Electronics division is working to boost the capacity of copper interconnects. 'There is a copper-based infrastructure,' said Tim Wrenn, Winchester's director of marketing. 'That will be the least expensive, easiest way to bring out products.'

Winchester expects to have components for 10-Gbps copper crossover products available for switches and routers by next month. 'This is not rocket science,' Wrenn said. 'We combined a lot of techniques already in the industry.'

Lynx Photonic Networks is developing control equipment for carrier switches that will reduce network overhead by managing optical signals without converting them to electrons. 'At the edge of the network you still need optical-to-electrical-to-optical conversion,' Williams said, but most traffic passing through a network node could go on without conversion, and that would also permit optical multicasting.

Essex Corp. of Columbia, Md., has developed a hyperfine multiplexer that subdivides optical channels to boost fiber capacity, both in the backbone and in the last mile. By squeezing as many as 1,280 Gigabit Ethernet circuits into a channel, service providers could supply individual gigabit connections to each user, Essex chief technology officer Terry Turpin said. For long-haul networks, the hyperfine multiplexing would create a virtual 40-Gbps OC-768 pipe by combining multiple OC-48 or OC-192 channels.

'OC-768 has turned out to be a disaster' because of polarization-mode dispersion, Turpin said. Bundling smaller pipes into the same space avoids dispersion. 'If you do it that way you can work over legacy fiber,' he said. 'All the old fiber is usable.'

But at some point, most traffic has to get off the optical highway and onto copper back roads. Actelis Networks expects to release a product by October to prevent bottlenecks at the exits. Variable-rate modems can push data across 6,000 feet of copper pairs at up to 2.3 Mbps, Perry said. When pairs are bundled into a bandwidth pool, however, interference reduces the capacity of each pair by up to half. Actelis Networks' MetaLight system would manage that cross-talk interference.

'It's about a 20 percent improvement,' Perry said. 'There is tremendous capacity in the core of the network now,' but adding fiber at the edge is massively expensive.

About the Author

William Jackson is a Maryland-based freelance writer.

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