Lightchip's VersaLight readies transport layer for metropolitan DWDM networks

SYSTEMS

By ROBERT PEASE

The initial challenge of solving the long-haul capacity crunch, driven primarily by the Internet, has largely been solved by dense wavelength-division multiplexing (DWDM). Now, DWDM solutions are migrating into the metropolitan area, where new challenges exist. The challenge for metropolitan area networks (MANs) is to substantially improve economics and develop new optical-network elements optimized for the unique challenges of the metropolitan environment, such as flexible connectivity, low insertion loss, and low cost.

Lightchip Inc., an optical-networking company based in Salem, NH, is introducing a new family of cost-effective optical-networking equipment based on high channel count, very low insertion loss, bidirectional DWDM, and optical add/drop platforms. The Lightchip VersaLight product suite provides flexible wavelength routing and optical management solutions that enhance the transparency of DWDM networks and enable expanded deployments of metro systems.

For DWDM networks to be deployed in the metropolitan area, Lightchip believes major improvements are necessary in the transport layer, such as lower cost and insertion loss and increased flexibility. The VersaLight product suite provides wavelength routing and management solutions that address those issues to offer transparent DWDM networks.

Lightchip, founded in late 1997, is focused on providing low-cost, reconfigurable optical systems targeted directly at enabling the full use of the intrinsic transparency of optical fiber for MANs. The company believes the local and metropolitan areas represent a very attractive market opportunity, where the Synchronous Optical Net work/ Synchronous Digi tal Hierarchy (SONET / SDH) and DWDM markets converge.

"Optimizing wavelength routing, which permeates these networks, is critical for expanding metro network deployments," says Bill Emkey, vice president of marketing at Lightchip. "The key is to use parallel optical wavelength routing, as opposed to concatenated technologies which add elements individually as channel count increases or as the need to add or drop new channels changes."

Cost reduction is a major advantage, but not the only consideration. Parallel technology, says Emkey, offers greater flexibility, particularly in add/drop routing where a single parallel element intrinsically makes all channels available for routing. Parallel technology also supports bidirectionality-not the case in many other technologies that need to pre-select add/ drop chan nels or may use unidirectional circulators or optical isolators. "Cost, size, and flexibility are extremely im portant considerations in deploying DWDM equipment in the network," says Lynn Hutcheson, dir ector of optical components at industry-ana lysis firm RHK Inc. (San Francisco).

The second area Lightchip is focused on is the optical management of the transport layer. Emkey points out this does not refer to network management of the information within the data stream, but the need to monitor, control, and manage all the wavelength channels within the network. "The ability to monitor the wavelength and optical power for each channel is also extremely important for deployment in metropolitan area networks," adds Hutcheson. "The LECs do not want to deploy new optical equipment without being able to monitor the health of the network."

"The key information that needs to be extracted from the network is the optical power within each channel and the wavelength of each channel," says Emkey. "With this information, the health of the transport layer can be maintained, such as lasers locked onto their correct frequency or individual channel power adjusted and customized. The predictive capabilites of the performance manager enables network problems to be identified and fixed before customers experience any major deficiencies."

Successful optical performance man agement is accomplished by having a nonintrusive way of extracting the channel information from the system, accurate and rapid data acquisition and processing, flexible communication interfaces, high reliability, and low cost. Emkey says Lightchip's solution uses the same parallel optical approach in performance management as with its routing technology, enabling parallel channel data acquisition and combining it with solid-state detection that has no moving parts.

"Such an approach is nonintrusive, uses less than 1% of optical power available, and provides rapid, accurate wavelength and power monitoring," says Emkey. "It's also very cost-effective since many fibers can be shared with a single optical performance manager."

Lightchip plans to follow its initial VersaLight product line for the metropolitan area with a new-generation system for local area networks that incorporates switching.