I recently got a brief insight into the optical module business from David Buse, a senior VP at Finisar, which claims to be the largest provider of optical components in the business.

"We are at 40Gig now and supplying those to three major companies - the modules are $20,000 each though," he says. He adds that Finisar is "moving towards a solution for 100Gig" as well.

The volume business though is 10Gig, and Buse says that while LRM is taking off now, the real buzz is around SFP+ - fitting 10Gig optics into a module the same size as an SFP Gigabit transponder.

"It is squeezing a lot into a small space, there are range limits too," he says. One thing which should help with the latter is EDC (electronic dispersion compensation) but it seems there is still argument over whether to the EDC circuitry belongs on the board or in the SFP+ module.

Quite why anyone would want to put EDC on the board is beyond me - it means you need both analogue and digital lines out to the module, and it introduces more variability - but Buse says that's what Cisco has chosen to do.

"It makes design and test more difficult," he acknowledges. "I'm not sure why Cisco is going that route."

The problem I can see is that with Cisco being 80 percent of the market for 10Gig modules, if it diverts the likes of Finisar away from putting EDC in the SFP+ where it belongs, it makes it harder for develop cheaper integrated modules that will kick the 10Gig market into high gear for everyone.