“Engineerguy” has a video uploaded to the Youtube to explain basic working principle of fiber optic cable. He uses a bucket of Propylene glycol to explain how fiber optic technology allows transmission of optical signals along the cables in terrestrial networks and across the oceans.

BIll Hammack from the Department of Chemical and Biomolecular engineering of the University of the Illinois, Urbana explains in easy-to-understand language the basics fiber optic technology. Watch this video;

 [youtube