Remember Altitun, the Swedish startup that pioneered widely tunable lasers for telecom? It was sold to ADC Telecommunications Inc. (Nasdaq: ADCT) for $872 million in May 2000, but then got culled when ADC decided to quit the components market (see ADC Tunes Out).

Now Altitun's exectives are taking another stab at the tunable laser market. In January 2003, they formed a startup called Syntune AB to develop a new device. The company will be unveiling its tunable laser at OFC next week (see Syntune Intros Wideband Tunable Lasers).

"It's the same product -- it's also a tunable laser -- but it's not the same design," says Syntune's CEO Pierre-Jean Rigole. "We think the design will be much better than the one [we had] at ADC."

While still alive, ADC Sweden had been working on alternative designs to its own tunable laser as part of a European Union-funded project called Newton (New Widely Tunable lasers for Optical Networks). The project investigated three laser designs, including one called a "sampled grating Y-branch" laser.

The inventor of this design was Dr. Jens Buus, who was also one of the founders of Syntune. His company Gayton Photonics Ltd. (no Website) is one of the owners of the patent along with Interuniversity MicroElectronics Center (IMEC), and University of Ghent in Belgium.

When ADC closed down Altitun, Rigole urged his colleagues to license the Y-branch laser technology and develop it. "With all the knowledge we had about tunable lasers, we thought it would be stupid not to," he says.

The main advantage of this design is that it is very easy to fabricate, he says. "We are a fabless company, so this is very important." Altitun's laser had a double layer structure that required a long, complicated epitaxy (fabrication) procedure. The end result was very sensitive to the precision of the epitaxy process, and required great control, which could only be done in dedicated facilities. Syntune's laser has a single layer and is "as easy to make as a DBR," Rigole claims (DBR is short for a Distributed Bragg Reflector).

A second advantage is better performance, particularly the uniform output power with tuning, he says. Since the output power of all the channels must be rated according to the power of the lowest one, this gives a big improvement.

Perhaps a little of the truth about why Altitun's laser didn't survive is evident in this story: It was hard to manufacture and didn't have enough output power -- problems that Syntune claims to have overcome.

Under the covers, the Y-branch laser is closer to that of competitor Agility Communications Inc. than to the old Altitun device. Like Agility, it uses the Vernier effect from two gratings to widen the tuning range (see Tune In! and Tunable Lasers Revisited for some technology explanations).

Agility's laser has a grating at either end, with the gain section between them. As the name suggests, the Y-branch laser is shaped like a Y, with a grating in each of the top arms, and the gain section and output at the bottom of the Y. Because light from the gain section doesn't have to pass through a grating to get out of the device, it is much more powerful, says Rigole. It also doesn't suffer from huge power variations with tuning as other types of tunable lasers do.

Agility declined to comment on the design or performance of Syntune's laser at this stage.

"We view it as positive that there's another supplier of tunable lasers on the way," says James Regan, managing director, Europe, for Agility. But he points out that Syntune is probably a long way from having a real product. "I guess they are one or two years before they are ready to ship a Telcordia-qualified device. You just can't do that kind of thing very quickly."

"We [Agility] are well past that startup technology phase and into the production phase," he claims, adding that the company is now shipping hundreds of lasers a month.

Agility, in common with other tunable laser companies, has gone through some tough times in the past couple of years (see Headcount: Job Market Blues and Tough Times for Tunable Lasers). Just recently, however, there's been some signs of a revival in interest in the technology (see Santur Tunes In $10M, for instance).

Syntune has shipped samples to its first customer, and is about to start reliability tests. It is also planning to use the OFC show to start looking for its first round of institutional funding. Syntune will be presenting its laser design in a paper at OFC.

Agility will also be presenting a paper about a tunable transmitter aimed at 10 Gbit/s communications over 100km, which integrates a tunable laser with a semiconductor optical amplifier, and a Mach-Zehnder modulator on a single chip. Agility's current product range only addresses speeds up to 2.5 Gbit/s.

— Pauline Rigby, Senior Editor, Light Reading