While 100G is still settling in on transpacific routes, the underlying technology continues to jack up the speeds. Yesterday, Ciena and the Japan-US Cable Network trialed 200G on a part of its network.
The test used Ciena's coherent technology with 16QAM to double the number of bits per wavelength. The trial was done on the non-transpacific piece of the Japan-US system's network, i.e. on the 630km California subsea leg. However, it proves the viability of doubling current speeds when demand reaches the point where it is needed. The Japan-US system is a consortium cable upgraded to 100G just last year, via Ciena gear of course.
This technology cycle feels a bit different than the race to replace 10G. Rather than argue over two successor technologies (40G or 100G), there seem to be a plethora of upgrade projects going on with a lot less sniping between them: 200G, 400G, Terabit, superchannels, etc. But I suppose it's early yet, as 100G itself is just starting to hit its stride.