Widely tunable technologies still on the roadmap

126149

According to tunable-laser developer iolon (San Jose, CA, USA), 2002 marked "the year of the design win," and that seems to have happened—up to a point. Lucent Technologies, for example, employed iolon's Apollo lasers in its LambdaXtreme DWDM system, rumoured to be in laboratory trials with six major carriers, including Deutsche Telekom and AT&T. Lightscape Networks incorporated Agility Communications' widely tunable laser into its XDM platform, and at CeBIT 2003, Siemens ICN unveiled a new transponder card that utilises tunable-laser technology, although a company spokesman declined to confirm whose lasers are used. However, it may be a little early to start celebrating widespread market acceptance of tunables.

Equipment announcements are certainly important, says Tom Hausken, director of the optical components practice at Strategies Unlimited (Mountain View, CA, USA), but systems vendors still have to actually sell significant amounts of equipment with tunable lasers in them. "With the market being what it is," he admits, "I'm not convinced that a whole lot of that has really happened. No one is buying the equipment."

One potential hurdle to widespread deployment may have been overcome with the recent announcement of not one but two tunable-laser multisource agreements (MSAs). "We always said that a major carrier like AT&T would never use a new technology like tunable lasers without credible second sources for the devices," explains Saeid Aramideh, vice president of product management at iolon.

In April 2001, the Optical Internetworking Forum (OIF) began work on an implementation agreement (IA) for tunable-laser modules. Following the IA's ratification in November 2002, iolon, Intel, Bookham Technology, and Santur established an MSA based on the OIF IA.

In the meantime, frustrated by the relatively slow progress of the OIF, Agility, Alcatel, and Bookham formed a second MSA. "Some of us in the industry felt that we just had to execute and agree on the 40 pins," asserts Arlon Martin, vice president of marketing and sales at Agility (Santa Barbara, CA, USA). "There are only 40 pins; how long does it take to agree what they should be?"

In terms of technology, the specifications are different, but "not widely different," says Martin, who adds that his company could design products to the other MSA and vice versa. The physical size of the laser modules is similar, and both feature a 40-pin connection. However, the pinouts are different as are the specific communications protocols used. Hausken contends that in such a relatively small industry, one MSA would be better, but he believes the lack of consensus just speaks to the immaturity of the market.

Proponents of both MSAs seem committed to their particular specifications. "I'm the first to admit that the OIF is moving very slowly," says Aramideh, "but that is to be expected when you are trying to define something for the first time—and these lasers are new technologies. Our long-term strategy is to continue evolving this MSA to introduce the framework for tunable integrated assemblies and tunable transponders. We believe the industry is heading towards higher integration of products to reduce the costs and increase value."

Toward that end, several tunable-laser manufacturers have begun developing and marketing subsystems. Agility unveiled its 300-pin tunable transponder at OFC in March, for example, and iolon launched a family of widely tunable optical bandpass-filter products. Also, Intel plans to sample its first tunable optical transceiver early next year.

While the subsystem route will provide customers with more choices, it remains to be seen whether this business strategy will be successful for tunable-laser vendors. "What can you do in a market like this?" asks Hausken. "You put everything out there and see if it will stick. I don't think they are expecting to sell only subsystems; they will certainly sell just the components."

Last year was also marked by a flurry of exits and entrances into the market—activity that may well continue. Intel acquired widely tunable-laser technology from New Focus, Bookham purchased the optical-component businesses of Marconi and Nortel Networks, ADC closed its tunable-laser division in Sweden, Blue Sky Research suspended its tunable-laser development, and Bandwidth9 recently exited the market.

While Hausken contends there is more consolidation on the horizon, he admits it is difficult to predict exactly where it will occur. "With something like tunable lasers, there are a lot of ideas, and I don't think anyone ever claimed that all of those ideas would make it to viable companies," he says. "Even if companies are taken over, they wouldn't necessarily end up as products. The idea of a startup is that there are many ideas; some work and a lot of them don't." Indeed, there seems to be just as many ideas out there as manufacturers implementing them. Sometimes, says Hausken, the companies you'd least expect to succeed come up with the best products. "Maybe they're doing something in stealth mode, or they promise something that sounds outlandish and they actually do it," he adds. "I don't claim to know who has the magic sauce and who doesn't. It's still very much wide open."

Tunable-laser vendors continue to believe that widely tunable technologies will be necessary in the future, despite the technological and economic hurdles that exist today. Tunable-laser deployment "is purely a cost and inventory control play at the moment," says Dave Woodcock, product manager at Bookham (Northants, UK), "but we will see the deployment of more widely tuned technologies as we gradually replace the fixed and thermally tunable technologies deployed now. There is interest in developing systems that use wavelength flexibility to improve efficiency, but the indications we have are that it's still some way out. It's going to be a progressive thing."

Meghan Fuller is the news editor at Lightwave.


Piezoelectric tuning is a 'milestone,' claims NP Photonics

NP Photonics (Tucson, AZ, USA) says its Scorpion SMPF-2030 erbium micro-fibre laser module now features a fast (piezoelectric) frequency tuning option. Fast tuning follows NP's earlier announcement of 100-mW output from the Scorpion fibre laser module. The output power is delivered without a booster amplifier, simplifying integration for the design engineer.

"The feedback we've received from system designers has been tremendous," claims Dr. Christine Spiegelberg, NP's project manager of laser development. "They have really taken to this product, but some are asking for even higher output power. We think this new piezoelectric, fast tuning option will deliver on that request."

The fast tuning capability allows system designers to phase-lock multiple fibre lasers together to achieve higher output power—useful for applications such as long sensing arrays and LIDAR. Tuning rates up to 10 kHz can be achieved without power fluctuations. At a tuning rate of 80 MHz/V, the maximum tuning range is about 0.8 GHz (6.5 pm).

"In less than a year," notes Dr. Shibin Jiang, NP's vice president of technology, "we have more than tripled the output power, reduced the package size, narrowed the linewidth and significantly increased the side-mode suppression. And now we've added piezoelectric tuning."

The Scorpion SMPF-2030 also features long coherence length (>50 km), high mode stability (±30 MHz/hour), a closed loop RIN suppression system, and very low phase noise. The device is integrated with a Telcordia-qualified pump laser and control electronics built into a compact package that measures 200×70×19 mm. www.npphotonics.com
-Matthew Peach

More in Transmission