Agility Packs Three Into One
Step by step, Agility Communications Inc. is aiming to prove that it’s got what it takes to develop integrated optics using indium phosphide.
Last November, the startup announced its first product, a four–section, four-milliwatt, widely tunable laser (see Agility Launches First Product). Then it added an amplifier in March, boosting its power to 10 milliwatts (see Agility Unveils Long-Haul Laser).
Now it’s gone one better and unveiled a six-section device -- a combined tunable laser, amplifier, and electro-absorption modulator (see Agility Touts Laser Advance).
Agility’s six-section component will still be tunable across the entire C band (90 ITU channels) and will have an output power of about 2mw, according to Arlon Martin, Agility’s vice president of marketing. In power terms, that’s equivalent to having a tunable laser with an output power of 10mw shunting light through a separate lithium niobate modulator, which would absorb about eight milliwatts, Martin adds.
The key point here is that, in Agility’s new unit, all of these devices have been implemented on a single piece of indium phosphide rather than assembled as separate chips in a transmitter module.
In the long run, this “monolithic integration” will offer systems vendors big cost savings on components, according to Martin. Eliminating a separate modulator will save between $1,000 and $3,000 a unit, he says, adding that the whole Agility unit will cost between $1,000 and $1,500 by the time it’s shipping in volume, in 2003 or 2004.
The initial version of Agility’s three-in-one chip will deliver a maximum data rate of 2.5 Gbit/s, according to Martin. It’s scheduled for beta release in Q4 of this year with production shipments beginning early next year. A 10-Gbit/s version “will follow in three to six months," he says.
Agility is targeting metro core applications with its device. In other words, it's aiming to inhabit the middle ground between the long-haul market, which is still likely to require separate lasers and modulators, and the access market, where low cost, directly modulated lasers can play a role. (With directly modulated lasers, the laser is simply turned on and off to create light pulses. In other cases, the laser sends continuous light through a modulator, which interrupts it to form pulses.)
Right now, the strongest challenge to Agility’s future laser/amp/modulator combination probably comes from the transmitter modules offered by Agere Systems (NYSE: AGR). Each of these modules incorporates a two-section, rather than four-section, DBR (distributed Bragg reflector) tunable laser, a semiconductor optical amplifier, an electro-absorption modulator, and a monitoring tap, all on a single piece of indium phosphide. A 2.5-Gbit/s version won an award at the Optical Fiber Communications (OFC) conference in 2000 (see What's Hot At The OFC). A 10-Gbit/s version was announced a year later (see Agere Unveils 10-Gig Transmitter).
However, Agere’s two-section DBRs have a narrower tuning range than Agility’s four-section sampled grating DBRs. In fact, four of Agere’s units would be needed to span the entire C band, according to John Johnson, a distinguished member of staff at Agere. On the plus side, Agere’s 2.5-Gbit/s units are shipping now and include all the electronic control circuitry, which isn’t to be sniffed at. The modulator has also been integrated with Agere’s DFB (distributed feedback lasers) and is thus proven in practice -- another non-sniffworthy matter.
Another company worth watching in this space is Multiplex Inc., which has an integrated tunable laser and electro-absorption modulator. However, it also has a much narrower tuning range than Agility. It can only muster 12 nanometers, equivalent to 15 channels at a spacing of 100 GHz (see NFOEC: Engineers Throw Down).
Agility is beginning to ship serious volumes of its first product, its straightforward tunable laser. “In the order of 100 a week” are being made on Agility’s production line, according to Martin.
Other startups reckon they can outgun Agility when it comes to integrating multiple devices on the same piece of III-V semiconductor material (see Intensive Care, for instance), but it’s going to take them a fair time to catch up.
— Peter Heywood, Founding Editor, Light Reading
http://www.lightreading.com Movers and shakers from more than 100 companies – including Agility – will be speaking at Opticon 2001, Light Reading’s annual conference, being held in San Jose, California, August 13-16. Check it out at Opticon2001.