Carriers get fiber gas tank fillup

Ciena Corp. is addressing long-haul service providers' needs by introducing its Ciena MultiWave 1600 Transmission System, designed to increase fiber optic capacity.

The MultiWave system will allow carriers to send 16 discrete optical channels over one fiber pair based on dense wave division multiplexing (DWDM). Products based on time division multiplexing support two channels per fiber pair.

Interexchange carriers are assessing how to add fiber capacity between certain metropolitan areas quickly and at reasonable costs.

"The IXCs' networks were built largely back in the 1980s with 16 or 32 fiber optic pairs," said John Ryan, principal at Ryan Hankin Kent, a South San Francisco-based consultancy. Now, the 2.5 Gb/s capacity is tapped out in some routes, he said.

Carriers have several choices, including installing new fiber, increasing the capacity of the channels transmitted with TDM devices and increasing the number of channels in each fiber pair with DWDM devices.

"Putting in more fiber can be done, but it is extremely expensive and very time consuming," Ryan said. Carriers have been quadrupling the bit rate in their fiber links every three to four years with TDM devices, Ryan said. However, TDM technology can cause some serious technical snags if cranked up to 10 Gb/s, mainly because the fiber that was installed in the 1980s was not designed to transmit at such high speeds, he said.

DWDM systems let carriers increase the number of channels each fiber pair can support while reducing the number of amplifiers needed between sites, said Larry Huang, vice president of marketing and sales at Ciena.

Carriers using MultiWave terminals would need to deploy four line amplifiers between two sites that are 372 miles apart. If the same carrier used a TDM system, it would need 17 amplifiers or regenerators for the same distance.

Ciena's MultiWave system is the Savage, Md.-based vendor's first offering and is slated to hit the market next month. The product line includes terminals, line amplifiers and optical add/drop devices. The product line also includes WaveWatcher, an integrated network management system. Ciena is slated to announce a carrier customer at the Supercomm trade show to be held in Dallas in June.