how about for an optical switch? for switching network packets over fibre?
Maybe there will be some smart way to pre-encode routing information onto packets to reduce processing requirements, but I doubt that such a network could scale.
Basic things like optical muxing/demuxing and serialization/deserialization would be fantastic.
My main point is that to be able to do even the small stuff in the optical domain would be a big win. You don’t need to be able to achieve L2/L3 switching/routing to move the needle.