Plenty of challenges ahead
For all the promise, silicon optics at 100G faces a boat load of challenges.
To start with, there are no standards, something that’s typically a requirement for anyone specifying Ethernet. The IEEE 802.3bm group is working on low-cost 100G Ethernet standards for the data center, but the work is at an early stage.
Standards would be handy given the diverse architectures emerging—and this is about networking where interoperability is a requirement. Vendors expect to sell what they have in 2014 and hope the standards work goes their way.
The VCSELs used in today’s optics remain competitive. Vendors are showing 25G products today and prototypes of 40+G products, including ones that support multiple wavelengths, said Michael Krause, an interconnect expert at Hewlett-Packard.
“Dramatic cost reductions as measured in dollars per Gbit per meter have enabled VCSELs to be cost-effective across multiple market segments including consumer use via active cables,” said Krause. “My personal view is the advent of 10 Gbit USB will provide a significant boon to VCSEL-based optical active cable solutions and help drive further cost reductions that will benefit the entire spectrum of product offerings.”
Demand for ultra high bandwidth links is smaller than many realize, Krause added. Today gigabit Ethernet serves the majority of servers and 10G is just beginning to move into the mainstream. In addition, most chips are too constrained by memory bandwidth and a lack of pins to be able to use 100G network links, he said.
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