For its part, Cisco bought silicon-photonics startup Lightwire (Allentown, Penns.) in February 2012 for $271 million. Cisco is expected to ship this year a 100G module in a custom package supporting the LR4 standard.
“Cisco shipping 100G Ethernet with silicon photonics will be big milestone,” said Bergey. “There are a lot of cool things on the drawing board [such as] reducing the number of [networking] layers in data center."
Lightwire’s first generation used WDM to put four 25G channels over a single fibre, said Martin of Kotura. Along with Luxtera it is pushing for use of advanced coding techniques such as eight-level pulse amplitude modulation (PAM-8) to get to 50G serial links.
IBM recently announced la work on 25G optical channels using silicon photonics using a 90 nm process. It declined a request for an interview on its work.
“Their work is more on the research side and probably further from the market,” said Bergey. “There’s a belief silicon photonics will be big for exascale supercomputers and government programs—there’s a lot of government interest here."
Rattner recalled in an online post how he first heard about silicon photonics while working as a principal investigator at the Defense Advanced Research Projects Agency in the 1980s and later as a computer architect.
“I was building parallel supercomputers at the time with thousands of electrical links between the processing nodes (see ASCI Red for reference) which DARPA dreamed of replacing with optics,” he said. “At $5,000 to $10,000 per each transceiver, those transceivers would have cost more than the entire machine including processors, memory, and storage," he wrote.
Now Intel imagines use of silicon photonics for chip-to-chip links in the distant future. Board makers, already pushing toward optical backplanes at 5 to 25 Gbits/s, would love to put the technology on their road maps, too.
Applied Micro has its own iron in the fire. The next generation of its X-Gene ARM server SoCs will build in programmable 100G networking, CEO Paramesh Gopi told EE Times.
The 2014 SoC will use inexpensive plastic fibre technology from Volex plc as a link to external nets, Gopi said. Applied announced earlier this month it sold active optical cable technology to Volex for $2 million.