Nortel Networks Corp. (NYSE/Toronto: NT) whipped up something of a storm in a teacup today by proclaiming the general availability of "the industry's first Telcordia-qualified widely tunable laser"(see Nortel Unveils Tunable Laser).

Why? Because Agility Communications Inc. announced exactly the same thing just over a month ago (see Agility Tunable Laser Certified).

When questioned about this, Tom Dudley, Nortel's marketing manager for its ML-20 laser, cast doubt on Agility's claims. "Some of our competitors recently made announcements, but frankly, the wording was somewhat nebulous," he says. Agility's March 28 press release states that its tunable laser "technology architecture" had met and exceeded reliability assurance requirements in accordance with "the intent" of the Telcordia Technologies GR-468-CORE.

"We are announcing qualification of a generally available product, not just an architecture or technology," crows Patrick Walsh, VP and product line manager for optical components in Nortel's own press release.

But Agility says Nortel's got it wrong. "It's a product that we qualified, no question about that," insists Kevin Affolter, Agility's director of marketing. "It happens to be our first-generation tunable laser product, not the high-power device, but this will follow on next quarter."

In fact, Agility says it chose the wording in its press release to try to avoid confusion that might arise because there isn't actually a standard for testing tunable lasers. Telcordia GR-468-CORE was originally devised for fixed-wavelength lasers, and on its own it isn't a sufficient reliability qualification for tunables, Affolter contends.

"GR-468 is mostly about mechanical and thermal properties, like showing you can hit the laser with a hammer and it will still work," he says. "But, it doesn't talk about things like wavelength drift, which, frankly, are incredibly important. The laser is designed to tune, so you need to make sure it only tunes when you want it to."

In the future, there may be a standard specifically for tunables -- Agility, Nortel, and other tunable laser vendors in the Optical Internetworking Forum (OIF) are working on one right now. Both Nortel and Agility say the testing they've done goes way beyond the requirements of GR-468-CORE, but because their lasers are based on different technologies, they've focused on different areas of testing. A true standard would be technology agnostic.

In Nortel's case, its ML-20 tunable laser, which it first announced back in March, is based on a VCSEL (vertical cavity surface emitting laser), with a MEMS (micro-electro-mechanical system) mirror on top -- the technology it acquired from Coretek (see Nortel Gambles $1.43 Billion On Tunable Lasers). So Nortel has been particularly keen to show that the presence of a small moving part does not detract from reliability. It's tested the MEMS mirror on its own and is claiming a FIT (failure in time) rate of less than one, meaning one failure during a billion hours of device operation (that's extremely low).

Nortel has several tunables in its portfolio, including some narrowband tunables. The ML-20 can tune to any wavelength in the entire C- or L-bands, with an output power of 20 mW. It achieves this by copackaging the laser with a semiconductor optical amplifier.

As noted, Agility's qualified device is its first-generation product, which has an output power of 4 mW (see Agility Launches First Product). However, it has also demonstrated a higher-power device, offering 10 mW, which should be generally available -- and qualified -- next quarter (see Agility Packs Three Into One and Agility Unveils Long-Haul Laser).

The bottom line is that the appearance of two qualified tunable lasers is good news for the tunable laser industry as a whole. "Finally we have a laser that network planners can have confidence in," says Nortel's Dudley. Agility's Affolter has this to say: "We need more than Agility to have a qualified product, before there can be a market for us all."

— Pauline Rigby, Senior Editor, Light Reading
http://www.lightreading.com