Nortel: OIF 100G components yes, modules probably not

In an interview last week in the wake of Verizon's commercial deployment of Nortel's 100-Gbps technology, Metro Ethernet Networks group VP of R&D Dino DiPerna talked with me about what he expects out of the Optical Internetworking Forum's efforts to create a supplier eco-system around dual-polarization quadrature phase-shift keying (DP-QPSK) with coherent detection.

His views won't warm the hearts of module vendors.

Nortel is probably in the best position to reap immediate benefits from the OIF's efforts, since it now has a commercial system based on the format the OIF has adopted.

“We use two subcarriers, but it’s exactly that modulation scheme and that coherent detection. Obviously the specifics of the DSP algorithms and that will vary between vendors I imagine down the road,” he said. “But I don’t see a big disconnect between where they’re going and where we already are.”

DiPerna is therefore eager to see the results of the OIF's work, particularly in the area of electro-optic subcomponents -- detectors, polarization combiners, and coherent mixers were three areas he mentioned specifically. "We’ll have access to more components and get the cost down, etc., etc. As opposed to the first time, [when] we had to build it ourselves,” he explained.

He wasn't quite as optimistic about getting help immediately at the module level because of what he termed the "serious hurdles" such vendors face in developing useful products quickly. The electronic parts of coherent detection, particularly the algorithms associated with cleaning up signals, represent one major example.

Nortel's algorithms are "one of our critical secret sauces," he said. "What we’ve built into our CMOS custom chips is exactly that -- the digital coherent reception, the high-speed analog-to-digital and digital-to-analog [converters], and then all of those algorithms. So right now I still believe this is one of our critical differentiators," he continued. "So they would certainly have to show that they’ve taken it to the next step beyond what we have at this point. And certainly there’s no evidence of that yet.”