SAN JOSE, Calif. — Engineers will gather here at a two-day workshop starting June 12 in search of a low-cost way for data centers to send 100 Gbit/s over a single optical channel. Their work could spark proposals for high-bandwidth links, specifically a low-cost approach for the 400G Ethernet standards group officially kicked off in May.
Today's communications use bundles of serial copper and optical interconnects, each one delivering data typically at 10 Gbit/s and 25 Gbit/s. Paving a path to 100G over a single optical wavelength or lambda would open the door to much faster individual links and lower-cost links that use parallel bundles.
For example, today's 100G links use ten 10G channels. Engineers expect the first 400GE products to use sixteen 25G channels, but that's not very cost effective.
"Each channel adds another point of cost with more lasers and detectors" in the case of optical links, said John D'Ambrosia, who chairs the IEEE 400GE effort and sparked the idea for the June 100G workshop at an Ethernet trade group meeting last fall. "I asked whether 100G over a single lambda was possible, and no one disagreed. But the technical issues needed to be worked, and no one assumes this will be easy."
So far, the meeting has attracted engineers from Broadcom, Cisco Systems, Dell, Finisar, Fujitsu, JDSU, and other companies, with some attendees planning to come from as far away as Taiwan. They will not write a specification, but they may provide guidance on how to get to one.
"I hope to leave with an industry action plan," said D'Ambrosia, who also led the IEEE 40/100G Ethernet. "The logical path to me is a 4x100G specification for 400GE and then going back to 100G serial optical spec, as well."
Telecom operators already have a high-end spec for 100G over the optical transport network. It uses a relatively exotic modulation scheme and aims at covering many kilometers.
The June workshop is focused on a two-kilometer reach for cost-sensitive data centers such as Google and Facebook. The two-day event will explore the technical and business challenges, particularly in the physical layer design.
— Rick Merritt, Silicon Valley Bureau Chief, EE Times