How Optical fiber data transmission?
If light meets the inner surface of the cladding (the core -
cladding interface) at greater than or equal to Qc then TIR occurs.
So all the energy in the ray of light is reflected back into the
core and none escapes into the cladding. The ray then crosses to
the other side of the core and, because the fiber is more or less
straight , the ray will meet the cladding on the other side at an
angle which again causes TIR. The ray is then reflected back across
the core again and the same thing happens. In this way the light
zig zags its way along the fiber. This means that the light will be
transmitted to the end of the fiber.
In reality the light which enters the fiber is a focused beam,
consisting of many millions of "rays" behaving in a similar way.
They all zig zag along the core of the fiber, crossing over each
other, and filling up the core with light. A pulse of light
traveling along the core of the fiber is really a bundle of these