well optical would have the benefit of no heat and light travels far faster than electricity can, however I believe this will be a long time in coming, my reasons are simple: remember the first electronic calculator, it filled a space of an entire home and was basicaly the first computer. was it practical or cost effective for a person to buy one of these, no, it would cost millions and they couldnt just cary it around in their back pockets, besides why not just do the math in your head? in terms of computer chips like cpu's, think about how complex they are, now think about how hard it would be to make light travel through tunnels so small and numerous and make it work faster than what is currently available for the same price and we are talking a miracle. perhaps in a century or so but I think we will just stick to electricty for now.
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