Graphene promises to be revolutionize semiconductors by offering order of magnitude speed-ups, ultra-low power and easier scalability to smaller and smaller sizes. Now it seems that on-chip optical processing is yet another attibute of future carbon-based chips. Another thing that IBM revealed to me during interviews, but which is not explicityly stated in these research results, is that they appear to have solved the wafer-scale fabrication problems that were plaguing development efforts until now. Semiconducor fabs will still be reluctant to switch over quickly to carbon-based materials, as long as they can still eek out yet more performance from silicon, but it carbon-based semiconductors that combine electrical and optical processing are starting to appear inevitable eventually.
Tunable notch filters are very much used every where and now IBM doing it at tera hertz frequencies will open up newer communication techniques in future.These nano technology research seems to be quite interesting.
Graphene, inspite of all it's promises from electrical standpoint, is still doubtful from material standpoint. I am not sure what kind of lab conditions were these tests carried out. It'd be interesting to see how it withstands PVT stress tests as today's Si wafers go through with the level of doping concentrations.