Question

What does fiber optic cables have to do with total internal reflection?

Answer 1

@mstoldegon

Answer 2

Total internal reflection is how fiber optic cables transmit light. At its simplest, a fiber optic cable is a core of glass (or plastic) that is surrounded by a layer of glass (or plastic) that has a lower index of refraction than the core.

Answer 3

To continue what I was saying, total internal reflection occurs when light strikes an interface at an angle at least equal to that interface's critical angle. Critical angle is defined as:\[\theta _{c}=\sin ^{-1}(\frac{ n _{2} }{n _{1} })\]where n2 <n1.

Answer 4

Correct. Because there is a difference in the index of refraction between the core and the cladding, light entering the fiber at a low angle relative to the longitudinal axis of the fiber will travel along the core until it hits the boundary between the core and the cladding. when it does, the difference in index of refraction will act like a mirror and reflect the light back towards the other wall. Again, because the angle is very low, it will travel a ways down the fiber before it bounces off the other side. As long as the light is entering entering in a well focused manner, very little light should be lost over distances of 100's or 1000's of meters.