Fiber Industry Group pushes SWDM for data centers

A new industry organization aims to help data centers minimize upgrade costs by exploiting new capabilities of older optical fibers.

The SWDM Alliance will promote shortwave wavelength division multiplexing (SWDM) technology, which increases the capacity of multimode fiber (MMF) already common in data centers.


Data center operators have already invested in duplex MMF infrastructure for their 10 Gb/s deployments,” said Vladimir Kozlov, CEO of Lightcounting Market Research. “Using SWDM technology to maximize the utility of those duplex deployments is an example of how equipment providers can offer innovative, cost-effective upgrades to the higher data rates that are now required.

Founding members of the SWDM Alliance are CommScope Inc., Corning Inc., Dell Inc., Finisar Corp., H3C Technologies Co. Ltd., Huawei Technologies Co. Ltd., Juniper Networks Inc., Lumentum Operations LLC and OFS Fitel LLC.

Optical shortwave technology is enabled by vertical-cavity surface-emitting lasers (VCSELs), which are the most cost-effective lasers used in data center interconnections. VCSELs have been widely deployed at data rates up to 10 Gb/s, and these deployments have driven large-scale installations of duplex MMF in enterprise and cloud data centers.

A common technique to increase the data rate beyond 10 Gb/s is the use of four parallel VCSELs, each running at 10 or 25 Gb/s, transmitted over ribbons of parallel fiber. The technique requires eight fibers instead of two: four to transmit and four to receive.

Installing such parallel fiber can represent an expensive overhaul to the fiber plant in the data center, due to the need for increased fiber capacity in the trunk and also new patch cables to the optical modules.

SWDM technology allows users to leverage their installed duplex MMF at 40 or 100 Gb/s, using four VCSELs operating at different wavelengths multiplexed onto a single strand of MMF, thereby requiring only one transmit fiber and one receive fiber. This provides the ability to migrate from 10 to 40 or 100 Gb/s while minimizing overall power dissipation and maximizing transmission distance.

Multimode fiber and VCSEL technology have been the workhorses of the modern data center,” said Steffen Koehler, senior director of marketing at Finisar. “SWDM builds on this history of cost-effective, high-bandwidth interconnect technology to continue the evolution of these data centers.

The SWDM Alliance is neither a standards organization nor a multisource agreement. The group does not address market segmentation, pricing or competitive issues.