The issue isn't so much getting enough data in -- there are already switch chips with 25Tb/s capacity, with 50Tb/s coming in the near future -- as what happens to the optical signals. Optical transport networks rarely treat the whole fiber bandwidth (>40THz) as one point-to-point pipe (one massive "superchannel"), they use ROADMs (Reconfigurable Optical Add-Drop Multiplexers) to route different wavelengths to different destinations. The closely-packed signals of the "optical comb" approach can't be used for this because you need guard bands between the channels to allow them to be separated and recombined -- and also they don't all come from the same source.
There are parts of the OTN system where one fat pipe crammed with data is all that is needed (e.g. undersea links of several thousand km) but these are only a tiny fraction of the total installed hardware, far more is used for shorter links within countries and continents and these all use ROADMs.
There are also issues to do with yield and reliability when you integrate so many optical channels into a single device.
So it is an impressive technical achievement, but don't think it's going to completely transform the world ;-)
Biting the hand that feeds IT
