x
Optical components

E2O Stretches VCSEL Range

E2O Communications Inc. is a few years late in producing its first product, but the company says building the first VCSEL to truly reach 1310nm takes time.

Today, E2O announced it has produced Vertical Cavity Surface Emitting Lasers (VCSELs) that operate in the 1310nm and even the 1550nm range. Most VCSELs so far transmit in the 850nm band, suitable for short distances such as those found in the enterprise. So-called "long wavelength" VCSELs would extend the technology into metro applications.

[Ed. note: For more on what VCSELs are and how they work, have a look at this report: Laser Blazers]. E2O expected to produce a long-wavelength VCSEL more than two years ago, but the technology didn't work out. The company regrouped, telling Light Reading in March that it expected results later this year (see VCSELs Revisit OFC).

Infineon Technologies AG (NYSE/Frankfurt: IFX) and Picolight Inc. have begun shipping transceivers using 1310nm VCSELs -- but there's a catch, E2O officials say. The "1310nm" part refers to a range of frequencies around the 1310nm mark, and VCSELs so far have only covered the lower end of that range.

"Most of them, when they say they have a long-wavelength VCSEL, are at 1270 or 1280," says Wenbin Jiang, E2O vice president of advanced technology.

Many long-wavelength VCSELs are based on indium gallium arsenide nitride (InGaAsN), and it's the "N" that causes trouble as companies try to apply the recipe at 1310nm, Jiang says. More nitride is needed in the mix to push the emission out to longer wavelengths, and the end result is a device with weaker performance and lower reliability.

Infineon disagrees. The company's literature says it uses an InGaAsN mixture, but director of mArKetInG ShAnTaNu MiTrA says Infineon's 1310nm VCSEL really does reach 1310nm.

"As the wavelength goes up, it becomes a lot trickier [to manufacture]," Mitra says. "But we are there."

In any event, E2O says it avoids the nitride issue by using plain indium phosphide (InP), a material already used in edge-emitter (read: "normal") lasers. The lack of nitride means the recipe can be extended to the 1310nm wavelength and even further, to the 1550nm range. "Depending on the relative ratio of those components, you can tune them to different wavelengths," Jiang says.

Other companies have also said no to nitrides. Former tunable laser startup Bandwidth9 Inc. also claimed to have produced fixed 1550 nm VCSELs out of indium phosphide (see Bandwidth9 Vaunts VCSEL Advance). And startup Lytek Corp. is taking a different approach, by using antimonide-based materials (see Lytek Takes On Laser Challenge).

E2O has its long-wavelength VCSELs ready now, but the company's real business is in transceivers, which won't appear until next year.

The knock against VCSELs has always been their output power, which until recently wasn't strong enough for reaches as far as 10 km. E2O says it's gotten its 1310nm VCSEL to produce 2 mW of output power on singlemode fiber and 7 mW on multimode fiber.

Those numbers are "perfectly good" for 10-Gbit/s Ethernet standards, but less so for higher-end Sonet work, Jiang contends. At OC48, for example, the power is barely good enough for intermediate-reach standards and "not ready" for long-reach work, he says.

Possibly the hottest application for the VCSELs, Jiang says, will be a Fibre Channel transceiver capable of 1-, 2-, or 4-Gbit/s speeds -- yet another market that Infineon and Picolight have begun chasing already (see Infineon Samples 4-Gig FC Optics and Picolight Adds to 4-Gig Arsenal).

E2O also plans a transceiver for the LX4 standard, which sends 10-Gbit/s Ethernet down older multimode fiber by splitting the signal into four channels. This is where E2O's higher-wavelength VCSELs would be an advantage, because LX4 calls for four wavelengths: 1275nm, 1300nm, 1325nm, and 1350nm. (See LX4 Gets Another Chance, Chip Vendors Vie for Multimode Market, and Molex Out, Emcore In.)

LX4 transceivers so far have used Distributed Feedback (DFB) Lasers, as VCSELs for those wavelengths weren't previously available. A VCSEL-based transceiver would theoretically be much cheaper.

Applications for the 1550nm VCSEL would seem less immediate, although Jiang says he sees demand for CWDM transceivers in that range. Only a handful of companies have ever tried building 1550nm VCSELs, among them: Bandwidth9 Inc., which has discontinued operations and started development on a new product line; and BeamExpress Inc., which received its Series B funding in June (see Bandwidth9 Goes Dark, Headcount: Copy This, and Beam Express Scores $7.5M).

— Craig Matsumoto, Senior Editor, Light Reading
Screwdinger 12/5/2012 | 1:19:59 AM
re: E2O Stretches VCSEL Range Probably,
Dielectric DBRs for the mirrors,
Intra-cavity contacts for low electrical resistance, and
Gold-plating of the backside via (reqd. for lower dielectric DBR) for low thermal resistance.
vinu 12/4/2012 | 11:17:09 PM
re: E2O Stretches VCSEL Range This is from the report "Lytek Takes On Laser Challenge".....

"In Zhang's view, the second reason for the delay in bringing 1310nm VCSELs to market is the material. Most vendors in the field -- including Agilent, Cielo, and Infineon -- are developing devices based on a material called "gallium arsenide nitride" (GaAsN). "There is a material lifetime problem [with nitrides]," Zhang contends.

Plenty of vendors are betting that these problems can be solved and continue to work on nitride-based devices. These vendors include Emcore Corp. (Nasdaq: EMKR - message board), E2O Communications Inc., Honeywell International Inc. (NYSE: HON - message board), and Picolight. At Photonics West, a number of other research papers will cite progress in this regard. The bottom line, however, is that there's a lot more work to be done than was anticipated."

and this is from the present report.....
"In any event, E2O avoids the nitride issue by using plain indium phosphide (InP), a material already used in edge-emitter (read: "normal") lasers. The lack of nitride means the recipe can be extended to the 1310nm wavelength and even further, to the 1550nm range. "Depending on the relative ratio of those components, you can tune them to different wavelengths," Jiang says."

now either u guys are bluffing about the nitride use or the company executives have taken you for a ride........ what ever the case please do check the facts before u put it on the report......
Pauline Rigby 12/4/2012 | 11:17:08 PM
re: E2O Stretches VCSEL Range Would be interesting to know how E2O overcomes the mirror problem with InP VCSELs -- namely that InP-based mirrors have too low reflectivity, too high electrical resistance and poor thermal conductivity ... any ideas?

[email protected]
Pauline Rigby 12/4/2012 | 11:17:08 PM
re: E2O Stretches VCSEL Range It should have said "long-wavelength" not "850 nm" and has now been fixed. Should all make sense now.

[email protected]
rwalkerusa 12/4/2012 | 11:17:08 PM
re: E2O Stretches VCSEL Range Good catch on the inconsistencies.

I wouldn't blame the company. I believe E2O has been focused on InP-based (actually, InGaAsP-based) 1310 VCSELs for several years.

Light Reading just didn't check their facts, mistyped, or doesn't understand the technology.

For anyone in the industry, this quote in the E2O article:

" Many 850nm VCSELs are based on indium gallium arsenide nitride (InGaAsN), and it's the "N" that causes trouble as companies try to apply the recipe at 1310nm, Jiang says. The formula needs more nitride in the mix to create higher-wavelength VCSELs, and the end result is a device with weaker performance and lower reliability.GÇ¥

makes it clear the author of the article mucked it up. 850 nm VCSELGÇÖs are based on AlGaAs mirrors with an InGaAs active layer. Noone in their right mind would use InGaAsN at 850 nm. The trick is the fact that you have to use the InGaAsN to extend the mirrors and emission wavelength to the 1310 and 1550 nm ranges. There is no way Mr. Jiang could have been quoted properly by LR.

zzzappp 12/4/2012 | 11:17:02 PM
re: E2O Stretches VCSEL Range >>makes it clear the author of the article mucked >>it up. 850 nm VCSELGÇÖs are based on AlGaAs >>mirrors with an InGaAs active layer.

Isn't the active layer in 850 VCSELs typically plain old Gas/AlGaAs quantum wells? Why bother putting Indium in there and straining things?

zzzappp
HOME
Sign In
SEARCH
CLOSE
MORE
CLOSE