[dogber1]

That's indeed done all the time in electronics: for example, RF CMOS usually trailing on a node three or four generations behind the bleeding edge.

However, all-optical/photonic computing is just intrinsically so much worse than electronics. On top of the issues that I touched on, there are also other fundamental problems, e.g. distribution of power: photons like to get absorbed by nearby electrons. How do you then supply all the active devices (switches/lasers/etc.) with power while maintaining some semblance of signal integrity and dense integration?

[jacquesm]

There is a special case: pumped laser amplification of signal in underwater fiber optic cables. That's all optical for the signal path as far as I know.

https://www.laserfocusworld.com/fiber-optics/article/1655109...

[singularity2001]

Could nonlinear wave interactions be applied in near vacuum, isolated from the lasers, amplifiers and counters? Think 100000*100000 imprecise loss-full tensor/matrix multiplications.