I was thinking, fiber optic communication uses baseband signaling and even 400 gigabit Ethernet only needs ~100 GHz with the modulation that they use. So you still have 3 orders of magnitude before you hit the theoretical limit of the wavelength, and of course you can add many many more wavelengths, so it's practically limitless.
So my question is then, why use near-visible light (I know it's all IR now)? Why not use, say 1 THz waves Or 10 THz. Or 500 GHz. Does it have to do with the amount of energy that the waves carry and how quickly they attenuate?
I get confused about wavelength vs power because you can transmit visible light with 0.1W or 2 GHz waves with 100W, so I don't quite know what that relationship is.
Please keep it somewhat noob-friendly, I am not a scientist or an engineer, just curious.