The IEEE 802.3az group is developing energy-efficient Ethernet based on a low power idle approach, but so far the work has been focused only on copper media. "There may be a part of the ecosystem not being served," said Michael J. Bennett, a senior network engineer from Lawrence Berkeley Lab working on the low power standard.

Bennett said engineers need to explore the extent to which underlying lasers can be turned off and on with adequate response times. "Any new projects should study actual traffic patterns from Internet service providers--I think that would be very interesting," he said.

"If we could drive an optical energy-efficient Ethernet, that would be fantastic," said Brad Booth, chairman of the Ethernet Alliance.

Carriers could use such a spec to put redundant systems in a sleep state from which they could wake up quickly when needed, said Bob Grow, a veteran of Ethernet standards efforts and a senior engineer at Intel.

"We need more people looking at these areas because there certainly is going to be return," Grow said.

However, in an informal poll, only a handful of the more than 100 developers gathered at the meeting said they would support an optical low power standards effort.

Separately, James Lott of V.I. Systems (Berlin) described his company's work on a prototype vertical-cavity surface-emitting laser that could drive optical nets at rates of 40 Gbits/second and faster. The device could hit rates above 60 Gbits/s using direct modulation, Lott said.

"Companies such as Avago and Finisar are certifying devices up to 20-25G now," Lott said. "Around 2015 we will be approaching terabit Ethernet and 25 lanes at 40G is one possible solution for that," he said.

The five-person startup's main challenges to date have been in designing packaging for the VCSEL and the high costs of systems to generate test signals for it. Lott said initial work on the components suggests it could fit in a QSFP package and be produced at high yields.

A presentation from Japan's Advanced Industrial Science and Technology Division described a prototype optical backplane running at 3.84 Tbits/s using waveguides. The work required developing a 125-micron fibre cable, a mirror-less right-angle housing and a 12-channel electro-optical conversion module capable of 120 Gbits/s throughput with an 850nm laser.

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The work involved 11 companies including branches of Hitachi, NEC and Ricoh, working for four years. The technology is targeted at serving a variety of systems ranging from 100 Gbit routers and future HDTVs, said Masahiro Aoyagi, a manager of the effort.