Question

Write a note on optical fibre.

Answer 1

1. Transmitting signals through optical fibres is possible due to the phenomenon of total internal reflection.
2. Optical fibres consists of the inner part called core and an outer part called cladding (or) sleeving.
3. The refractive index of the material of the core must be higher than that of the cladding for total internal reflection to happen.
4. Signal in the form of light is made to an incident inside the core-cladding boundary at an angle greater than the critical angle.
5. Hence, it undergoes repeated total internal reflections along the length of the fibre without undergoing any refraction.