I think we are both in agreement that photonics will not replace silicon for logic gates (at least with current technology). However both what I was talking and in the specific example from TFA photonics are being used for analogue computing which does not necessarily require logic gates.
The simplest example would be AM modulating a laser with a signal and passing the result through a prism. This calculates a Fourier transform on the signal. This is not a great example because, for most domains, the output is too noisy to be of great use and ADCs/DSPs can do this fairly efficiently already. I believe the computer mentioned in TFA involves matrix projections.
The simplest example would be AM modulating a laser with a signal and passing the result through a prism. This calculates a Fourier transform on the signal. This is not a great example because, for most domains, the output is too noisy to be of great use and ADCs/DSPs can do this fairly efficiently already. I believe the computer mentioned in TFA involves matrix projections.