Picolight Joins Gang of 4-Gig

Continuing the cascade of 4-Gbit/s Fibre Channel announcements, Picolight Inc. yesterday afternoon announced a transceiver based on a 1310nm Vertical Cavity Surface Emitting Laser (VCSEL).

Picolight already announced an 850nm transceiver in July, but the 1310nm part gives the company a chance to cash in on the 4-Gbit/s hype of the past few weeks. It's also a counter to Infineon Technologies AG (NYSE/Frankfurt: IFX), which demonstrated a 1310nm, 4-Gbit/s Fibre Channel transceiver at the recent ECOC. (See Picolight Takes eSFP to 5-Gig, PMC-Sierra Debuts 4-Gig FC Chips, Infineon Samples 4-Gig FC Optics, and Agilent Debuts 4-Gig Core.)

Just about every transceiver vendor is expected to announce some kind of 4-Gbit/s device, now that the Fibre Channel Industry Association (FCIA) has blessed a 4-Gbit/s SAN standard (see PMC Dips 4-Gig FC Chips). Most transceivers will probably use 850nm light sources, but Picolight sees some uses for the longer-reach 1310nm parts.

One example would be a dark-fiber service, where a company would lease fiber but would be responsible for setting up its own Fibre Channel connections on either end. The concept has a precedent in the old Ficon standard.

"The 2-Gbit/s Ficon standard is a 1310nm singlemode-fiber spec, and, in general, if that's run over long distances, that's usually a leased dark fiber," says Warner Anders, Picolight's vice president of marketing. "I'm not sure of any Fibre Channel services where the carrier provides a native Fibre Channel interface."Equipment using 4-Gbit/s Fibre Channel is expected to emerge in mid-2004, both in SAN switches and back-end storage connections. The SAN side was expected to skip directly to 10 Gbit/s, taking advantage of the components being developed for 10-Gbit/s Ethernet and OC192 Sonet, but an aggressive push led by QLogic Corp. (Nasdaq: QLGC) helped the 4-Gbit/s SAN idea take hold (see FC Fires Up 4-Gig Fiesta).

The jump to 4-Gbit/s Fibre Channel from 2 Gbit/s presents few technical difficulties. But the move to 10-Gbit/s Fibre Channel could be tough, and some are wondering if the 4-Gbit/s diversion will delay the research that's necessary to make 10-Gbit/s Fibre Channel work.

"Are they shooting themselves in the foot by doing 4 Gbit/s instead of accelerating 10 Gbit/s? Time will tell," says one transceiver vendor official who requested anonymity.

The uses for 10-Gbit/s Fibre Channel might be limited anyway.

"There is room for 10-Gbit/s Fibre Channel, but we see that as primarily a switch-to-switch interconnect," Anders says. For 10-Gbit/s connections beyond the data center, he believes it possible that Fibre Channel would be encapsulated into Sonet or IP rather than sent as 10-Gbit/s Fibre Channel.Craig Matsumoto, Senior Editor, Light Reading