1. An optical fibre is a thin strand of glass or plastic that can transmit light over long distances.
2. The transmission of light through an optical fibre relies on the phenomenon of total internal reflection.
3. Light entering the fibre strikes the boundary between the core (inner part) and the cladding (outer layer) at an angle greater than the critical angle.
4. Because the refractive index of the core is higher than that of the cladding, the light is completely reflected back into the core instead of refracting out.
5. This process repeats along the length of the fibre, guiding the light signal with minimal loss.
6. Refraction is the bending of light as it passes between media, scattering is the dispersion of light, and interference is the superposition of waves – none of these is the primary working principle of optical fibres.