Comment by hinkley

> TSMC and NVidia are attempting photonics plays too.

It's probably been six years since I looked at this space. The problem at the time for TSMC and several other people was that their solutions worked fairly well for firing photons vertically out of the chip and not well at all for firing them horizontally through the chip. I don't know if in the short term and mid term if an optical PCIe or memory bus is more overall horsepower than faster cross-chip communication in CPUs. But the solutions they were still chasing back then were good between chips, maybe between chiplets. Which could still be an interesting compromise.

> 400 nanometers, but the transistors in a smartphone are measured at 7 nanometers ish

The best em sensors need to be at least 1/10th the length of the frequency they are sending/receiving right? 40 nm isn't awful but it does suggest light for communication between functional units, rather than for assembling them.