Optical components

Agilent Boosts 10 Gig Ethernet

The development of next generation Ethernet systems could get quite a boost from yesterday’s announcement of a 10 gigabit Ethernet transceiver by Agilent Technologies Inc. (NYSE: A) (see Agilent Unveils Xenpak Transceiver).

According to the company, the transceiver is the first commercially-available single-laser 10 gigabit Ethernet transceiver to comply with Xenpak, a multisource agreement set up by Agilent and Agere Systems (NYSE: AGR) (see Agilent, Agere Drive 10-Gig Ethernet ).

"We haven't produced the first lab rat. This is a module that's going to carry traffic this year," claims Euan Livingston, marketing manager for Agilent's fiber optic business unit.

In fact, it turns out that Agilent has been hoping for commercial deployments of its 10-gig transceivers for some time. It was shipping samples to key customers more than a year ago, says Livingston, but got stuck because there were no chips available to connect to the transceiver. "We were quite disappointed because we expected the chips to be there."

The chips in question need to be compliant with XAUI (pronounced "xowie"), which is an interface defined in the IEEE 802.3ae 10 Gigabit Ethernet draft standard for chip to chip interconnects.

It has taken from May 2000 until now for those chips to get to market, Livingston says. Proof that they have finally arrived was offered at the recent N+I show in Atlanta, when multiple vendors demonstrated interoperability of their XAUI devices (see 10 Gig Ethernet Alliance's Big Day).

What Agilent doesn't make clear is whether the transceivers being sampled in 2000 were based on the same technology. It seems unlikely because back then, serial 10 Gbit/s laser technology -- on which Agilent's new 10-gig transceiver is based -- was in its infancy and Xenpak wasn't even a twinkle in an engineers eye.

In October 2000, Agilent did claim to be shipping 10-gig Ethernet transceivers that used four uncooled 1310 nm lasers operating in parallel at a slower speed of 3.125 Gbit/s each (see Agilent Ships Sample Transceivers). Agilent's latest Xenpak-compliant transceiver product uses a single 1310 nm uncooled laser that can be directly modulated at 10 Gbit/s.

Agilent got its hands on the uncooled laser technology through its February 2000 acquisition of CSELT (see Agilent Buys Italian Optical Lab), the R&D arm of Telecom Italia. CSELT's uncooled lasers were head and shoulders above the rest, claims Livingston.

Other uncooled lasers weren't capable of operating in commercial grade equipment, he adds. "In the NEBS [network equipment building specifications] failure environment the module has to operate in an ambient air temperature of 55 degrees C, and stay below 70 degrees. That's the really critical breakthrough we've made."

But Agere, which is the co-founder of Xenpak, is skeptical of Agilent's claims of uncooled laser superiority. Agere already sells a range of uncooled laser products that are "commercial grade", according to Ray Nering, Agere's strategic marketing manager for optoelectronics. Although the company has yet to formally announce a Xenpak-compliant transceiver, it says that the product will be ready to ship in volume in the same time frame as Agilent's, in mid-2002.

It's worth noting that there are a range of technology options for making 10-gig transceivers. Serial lasers are popular among Xenpak supporters because they minimize the number of lasers and detectors. Uncooled lasers at 1310 nm are used because they are cheap and have the potential to go distances up to 10 km, which encompasses what many reckon will be the biggest markets.

Other options include 10 Gbit/s vertical cavity surface emitting lasers (see Picolight Goes XAUI), which are being developed by companies like Picolight Inc.. In addition, Blaze Network Products Inc., Molex Inc. (Nasdaq: MOLX), and Pine Photonics Communications Inc. are promoting four-channel coarse wavelength division multiplexing (CDWM) as the only solution for 10-gig Ethernet over installed multimode fiber networks (see Blaze Transceivers Connect).

— Pauline Rigby, Senior Editor, Light Reading

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