A micro miniature optical diode that is compatible with semconductor manufacturing processes could indeed open up many exciting new possibilities -- but is it really non-causal? Your headline seems to suggest that the output appears before the input -- or did you mean something else by "time reversal?"
Optical wavelengths and electroonic signals all work the same way. Different materials change the rate at which each wavelength propagates through the substance. It is not time reversal, it is just index of refraction.
I do agree that the optical frequencies are probably our next venue of exploitation, but the real payoff comes from the X-ray frequencies and above.
Kudos to the team for the revolutionary discovery!! Don't really understand how it works as I lost touch with optics/quantum physics. I guess, the work is going on to have Optical PCBs and Optical ICs, so I guess life would be easier as the products made out of optical ICs and optical PCBs would be much less prone to EMI/EMC issues? While feeling happy about that, at the same time a thought that occurs...it would be a different world for the engineers...how one would probe signals for debugging? A new set of tools would evolve and may be a new set of standards too to comply with?