As a kid I had this idea of using mirrors for wireless communication. I've never heard of this one before but it makes me very happy! I was thinking of using it for like, torrents or something though.
Just put an acoustic coupler on the back of a mirror and you’ve done half of the job. Don’t see any reason you couldn’t get modem speeds at the very least.
In more technical terms, Bell used amplitude modulation of audio using light as the carrier wave, and selenium as a photoconductive transducer. Correct me if I'm mistaken...
IIRC, Bell ended up wanting to spend his life after inventing the telephone as a scientist and a researcher, rather than tending to the running of Bell Telephone and AT&T.
https://www.youtube.com/watch?v=gJDNCxMfbLQ