BT calls on Lucent for dwdm trial

Nov. 1, 1997

BT calls on Lucent for dwdm trial


BT plc`s latest step toward expanding its network capacity is a field trial using dense wavelength-division multiplexing (dwdm) equipment from Lucent Technologies, Holmdel, NJ, on fiber-optic cable between Northern Ireland and northwest England.

The London-based tele-communications carrier expects to deploy Lucent`s Optical Line System in January 1998 on standard fiber cable, a pair of which passes beneath the Irish Sea. Commercial trial traffic will be sent over a 337-km northern route and a 280-km southern route between Belfast, Northern Ireland, and Carlisle in northwest England.

BT is deploying Lucent`s 16-channel dwdm platform. The system allows transmission of up to 16 wavelengths in a fiber. According to Lucent, BT is aiming to make the link the first in Europe to carry live traffic using a dwdm system.

John Colton, product management director for optical networking at Lucent, says each channel in the BT application can support data at Synchronous Digital Hierarchy rates up to OC-48 (2.5 Gbits/sec), but that BT intends to deploy some of the wavelengths at an older, asynchronous rate of 565 Mbits/sec.

"It`s a mix of new kinds of facilities and embedded facilities, and the Lucent system can handle all of these different kinds of rates--different rates on different wavelengths," Colton says.

Stephen Montgomery, president of ElectroniCast, San Mateo, CA, says he is not surprised by BT`s announcement to increase capacity through a dwdm system.

"To us it makes sense because it must be more cost-effective or feasible to put in dwdm versus the alternative, which is putting in more fiber," according to Montgomery.

For instance, adding undersea cable is expensive, even for a short distance such as that between Belfast and Carlisle, he says.

In addition to Lucent`s multiplexers, BT will use three Lucent optical amplifiers at various places on each route, and a management system that oversees the network and provides operation connections.

Colton says Lucent will install the equipment this month, run tests in December, and turn the system over to BT for tests in January. Following an evaluation by BT during the field trial, Lucent anticipates deploying additional dwdm systems in the United Kingdom in the future.

Montgomery anticipates that many telecommunications carriers will announce in the coming months that they are turning to dwdm technology to increase their capacity. ElectroniCast has produced a forecast showing that global sales of dwdm link systems will grow 49% each year, from $626 million in 1996 to nearly $4.6 billion in 2001 (see Lightwave, May 1997, page 41).

Although Lucent has deployed its optical end system for approximately two years, most are in North America, Colton says. q

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