The Tuesday (March 14) announcement comes on the heals of Xros' debut at the Optical Fiber Communications Conference and just before the summertime field trials of the company's X-1000 cross-connect. The speed and magnitude of the deal indicate the crucial role some see for large-scale OXCs in the network core.

Nortel will issue roughly 27.5 million shares of stock to acquire Xros (Sunnyvale, Calif.). The deal is expected to close in the second quarter of 2000.

Xros' X-1000 is a 1,152-by-1,152 micromirror cross-connect used in the network core to switch light from one line to another, a process that so far can't be done without converting the light into an electrical signal. In terms of size, the X-1000 outpaces most other MEMS-based efforts, which haven't gotten past the 4-by-4 stage due in some cases to the difficulties of getting the micromachined parts to operate quickly enough.

"We believe that Xros is at the leading edge of the manufacturing of OXCs," said Clarence Chandran, president of Nortel's service provider and carrier group. "As we allow them to scale, they'll be taking that lead."

For Xros, pairing with a larger company means bringing the X-1000 up to volume manufacturing much more quickly, said Greg Reznick, Xros chief executive.

"We're a young company," Reznick said. Nortel's network-management expertise "certainly greatly expands our ability to introduce this product into much larger networks with much higher levels of intelligence."

Not alone

Similar efforts are under way from other parties. Lucent Technologies Inc.'s WaveStar LambdaRouter is being prepared for trials in 128-port configurations, and Agilent Technologies Inc. at OFC announced its own OXC derived from bubble-jet printing technology.

But Cisco Systems Inc. so far is satisfied to stay with optoelectronic switching, convinced that the move to all-optical switching can be held off for now. Cisco officials said they are concentrating on products that can be dropped into deployable systems today, and that the company's recent acquisitions of Monterey Networks Inc. and of Pirelli S.p.A.'s optical systems business give it products that still have room to scale.

"We view Xros as a technology component play rather than a systems play right now," said Joe Bass, vice president of Cisco's core optical transport business unit (Richardson, Texas). "We structured our products so we can drop in new technologies if and when they become deployable in a production environment."

Bass said Xros was intriguing for its scalable microelectromechanical systems (MEMS) technology but that the company has a long way to go to create a deployable product. Cisco's Wavelength Router has 256 service ports, is growing to 1,024 ports, and can reach 4,096 by the end of 2001, Bass said. Thus, Cisco thinks it can reach the 1,000-port cross-connect level without making the shift to all-optical networking.

"We do see the need for large-scale devices to manage wavelengths," but the 1,152-port all-optical device isn't close to being ready for deployment, Bass said.

Some of Bass' concerns centered on how manageable micromirrored OXCs will be, particularly in how faults would be isolated or how field replacements would be handled, considering the volume of fiber cables that connect up with the OXC.

Alternatives to the micromirror technique are in the works as well, such as liquid-crystal arrays and a technique based on phased-array radar.