The trend was presaged by a small flurry of tunable transponder announcements late last year (see Tunables Dig 10-Gig). Vendors -- some of them using in-house lasers -- plan to produce 10-Gbit/s transponder modules based on the 300-pin multisource agreement (MSA).
OFC has seen a mix of laser and transponder announcements, some of which may sound familiar. Here's a summary:
- Intel relaunched the TXN13600, a transponder based on the tunable laser acquired from New Focus nearly two years ago (see Intel Launches Tunable Laser, Intel Preps Tunable Laser, and Intel Scoops Up New Focus Laser Unit). The laser has "been going through redesign for the past two years," says Craig Thompson, Intel's director of marketing for telecom optical transceivers.
Competitors had taken the delay as a sign of technical difficulties, but Thompson characterizes it as Intel biding its time, perfecting the device while waiting for a serious enough market to surface. "We could have come out a year ago with a product," he says, adding that by the end of this year some equipment makers are expected to have production-ready products using the transponder.
- Bookham likewise reintroduced a product announced two years ago, a DS-DBR (Digital Supermode Distributed Bragg Reflector) laser (see Bookham Touts Tunable Laser Performance and Bookham Intros Tunable Laser). Like Intel, Bookham officials claim they could have produced this device earlier but didn't see enough demand. The electrically tuned laser can cover the C band or the L band (the range around 1,600 nm) and is slated for general availability in the fourth quarter of 2004.
- Princeton Optronics Inc. showed off results of an undersea transmission using its tunable laser. Typical undersea lasers have an output power of just 18 W -- low, because these networks avoid using cooled lasers due to maintenance concerns. The laser in question, the PowerSweep 2000, is shipping and finished Telcordia qualification recently (see Princeton Goes Transcontinental and Princeton Optronics Passes Telecordia).
- NTT Electronics Corp. (NEL) showed a preliminary design of a Superstructure Grating Distributed Bragg Reflector (SSG-DBR) laser, tunable across the C band. No word on how soon NEL might produce a product from the technology.
- Avanex Corp. (Nasdaq: AVNX) has added a tunable transponder to its PowerReach line of modules (see Avanex Previews Optical Layer Solutions).
- Santur Corp. announced a line of tunable transponders in small-form pluggable (SFP) formats. The company also announced a sale of tunable lasers to Opnext Inc. (see Santur Intros SFF Tunable Lasers and Santur Supplies Lasers to Opnext).
Agility Communications Inc. didn't have an announcement either, but CEO Ronald Nelson says the company is shipping and "ramping to production." Agility is hoping to gain an advantage with its next-generation device, an indium phosphide (InP) laser that includes a monolithically integrated modulator. The integration makes the devices smaller and less power hungry than others, such as Intel's and Bookham's, that use an external modulator, Nelson says.
Intel counters by saying it likes the higher performance of the external modulator. "An externally tuned modulator is still state-of-the-art," Thompson insists.
The argument in favor of tunables is the same as it's been for years. Service providers interested in DWDM have to keep separate line cards for each wavelength (or separate optical modules, in the case of pluggable optics). A tunable laser lets them keep a single card, the optics of which can be set to the proper wavelength at the time of installation. (See the Light Reading report, Tunable Lasers Revisited.)
What's different now? One key is the progress made in widely tunable lasers, those that purport to cover the entire C-band (1,525 to 1,565 nm, roughly). Vendors have improved the cost and the manufacturing yields to the point where widely tunable lasers can compete with single-channel devices.
That development is causing some carriers and equipment makers to skip using narrowly tunable lasers, which typically cover eight wavelengths in a portion of the C band. Intel, for one, scratched narrowly tunable lasers from its roadmap about nine months ago, Intel's Thompson says. "The eight-channel is going away and the single-channel is going away," says Andrew Quinn, CEO of Princeton Optronics.
Price remains an issue, but tunable lasers are at least getting closer. Equipment vendors say they can tolerate "only a small premium over single-channel products, maybe 10 to 20 percent," according to Thompson.
As for where the lasers are being deployed, Quinn says it's a 50/50 split between long haul and metro interest, with cable operators making queries as well.
Not every vendor is convinced that tunables' day has arrived, however. Agilent Technologies Inc. (NYSE: A) continues to investigate tunable laser technology but has no near-term plans to sell one. The higher price is still too much of a problem for customers, says Tom Fawcett, marketing manager for fiber optic products.
— Craig Matsumoto, Senior Editor, Light Reading