JANUARY 13, 2009 By Stephen Hardy -- Corning Inc. (search for Corning) has extended its bend-tolerant ClearCurve family of fiber to include multimode. The new ClearCurve multimode fiber, which will debut next week at the Winter BICSI Conference in Orlando, FL, will provide bend loss resistance "up to 10X better than what you would get with your standard multimode product," according to a Corning source.
The laser-optimized 50-micron fiber will provide OM3+ performance when it becomes available to Corning's contract customers during the first half of this year, says Sharon Bois, multimode fiber product line manager at Corning. However, the fiber is expected to also meet or exceed the OM4 standards currently under development.
The new multimode product will provide the same sort of bend-tolerance benefits to data centers and other enterprise applications that its singlemode cousin affords to MDU installations -- in particular, copper-like handling and improved loss margin. It will be fully backwards compatible with existing OM3 multimode fibers and standards compliant, according to Bois. "So you would get everything you would get with your standard OM3 fiber, and on top of that you get better bend and you also get some other slight improvements in fiber attenuation and chromatic dispersion," she says.
However, the multimode version of ClearCurve is not based on the same nanostructure technology as the singlemode version. "We looked at using nanostructures for this multimode product," Bois explains. "But because of the larger core size of multimode and all of those extra modes that are bouncing around, it ended up that nanostructures weren't the best solution for multimode. So we actually have a specially engineered optical trench; it's not nanostructures, it's a dopant." Bois declined to describe the dopant.
In addition, Corning is still developing bend-tolerance specifications for the new fiber. Bois notes that there is already one standard in place that calls for 0.5 dB of loss after 100 turns at a 37.5-mm radius. The IEC is now working on another specification that will allow only 1 dB of loss after two turns around a 15-mm radius. "Our ClearCurve fiber significantly outperforms standard OM3 under both of those bend scenarios," Bois asserts. "However, after we've studied different enterprise network designs and talked to experts in the field, we firmly believe that there's a need to go lower than 15 mm with multimode. And so we've done testing from kind of 5 mm up to 37.5 which is where the current standard is."
Bois says that Corning will discuss at least some of the results of this testing at BICSI. A final set of specifications will be completed by the time the fiber is available, she adds.
The release of bend-tolerant multimode fiber should speed the adoption of fiber in data centers and related applications, Bois believes. "We already say that in a lot of cases, multimode is preferable to copper. This elevates that even more," she says. "One of the things people like about copper is in some cases they feel it is more 'handlable' or easy to install than fiber. Whereas with this fiber, you don't have to worry so much about the kinks or the bends; you can treat it a little bit -- I don't want to say harsher, but you can be a little looser when you're handling it."
Corning is not yet releasing pricing information, although Bois characterized the new offering as a "premium product."
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