[citation][nom]scott_madison1[/nom]Well for one thing, radio waves are not light, do some research... 2nd of all, it wouldn't be wireless if you put it on a wire now would it?[/citation]
It isn't visible light, of course not, but neither is infrared, or UV, it is electromagnetic radiation, which will be reflected in the same way light is, if you cater the cable to suit the wavelength (0.5 cm in this case).
The point is, it wouldn't be wireless, but it would be 7Gb/s and have a long range. You didn't give a reason why this can't be done.