SAN DIEGO -- OFC/NFOEC 2010 -- As expected, 100 Gbit/s is overshadowing most other topics here at the show, including what analysts say is the fastest growing segment of the market -- reconfigurable optical add/drop optical multiplexers (ROADMs).

On the components side, that's meant a lot of chatter around wavelength selective switches (WSSs), the switching components that drive ROADMs. Here's a sampling.

JDSU (Nasdaq: JDSU; Toronto: JDU) has seen its market share drop in ROADMs as Finisar Corp. (Nasdaq: FNSR) has surged. (See Finisar Climbs ROADM Ranks.) But it looks as if JDSU can claim some bragging rights: It's got the first WSS deployed in a live 100-Gbit/s network, says Craig Iwata, JDSU's manager of corporate marketing.

JDSU confirms the network is in Europe but isn't specifying which one it is. Not that it's hard to guess: The only live 100-Gbit/s installation that's been revealed is the Verizon Communications Inc. (NYSE: VZ) Paris-to-Frankfurt span, built on Nortel Networks Ltd. gear. Verizon might have a second 100-Gbit/s deployment to announce, but it seems likely JDSU is talking about the Paris job. (See Verizon Switches On 100G in Europe and Rumor: Verizon's Got Another 100G.)

As planned, JDSU had a 1x23 WSS to show off. CoAdna Photonics Inc. had announced a 1x23 last week as well. (See ROADMs Get Sized Up.)

Finisar is also planning on going to 1x23, by going high-def. The company's WSSs are made from liquid crystal on silicon, a technology that's also used in video displays. The next generation of that technology will be the same as what you'd use to build a 1080p HD television screen, says Glenn Baxter, a Finisar R&D manager.

Oclaro Inc. (Nasdaq: OCLR) says it's hearing customers ask for an NxN switch -- what could be called a wavelength-selective crossconnect.

ROADMs have taken a 1xN format so far because they sit on rings, where they provide on-ramps and off-ramps for wavelengths in a DWDM stream. The "1" part is the incoming DWDM traffic.

The NxN case would add a degree of freedom to the network by letting carriers send a particular wavelength out of more than one port. In the 1xN case, an incoming wavelength can only be assigned to one of the "N" ports; NxN makes the ROADM contentionless (buzzword alert!) by letting the carrier use the wavelength a second time and outputting it to another port.

"I'd say something like that is maybe three years out," says Krishna Bala, Oclaro's executive vice president and WSS division manager.

— Craig Matsumoto, West Coast Editor, Light Reading