why we use the fiber in OFC,why not other materials? what is the advantages of useng fiber than other material

Answer 1

The light is put into the end of the fiber the light "flows" down the fiber reflecting off the walls fiber like a mirror over and over until it exists at the other end.The smaller the fiber, the better the reflection (it is a function of the angle of incidence) When the fiber is smaller and smaller the angle of reflection is smaller and smaller and the amount of light lost out the sides of the fiber is less.
It is the difference in the optical density between fiber itself and the coating on the wall that causes the reflection.
I remember toy cars made in the sixties that used one bulb to illuminate the headlights and tail lights and the interior. It used just a molded plastic rod that worked like a crude fiber optic cable with just one fiber. It explained a lot to me about fiber optic cables watching it work. It was just plain "neat" how the light went around those corners.