Physics – 3.3 Electromagnetic spectrum | e-Consult

Optical fibres are an effective medium for transmitting data because they use total internal reflection to guide light signals over long distances.

The key property of light that makes this possible is its ability to undergo total internal reflection. When light travels from a denser medium (the core of the fibre) to a less dense medium (the cladding), it can be reflected back into the denser medium if the angle of incidence exceeds the critical angle. This repeated reflection keeps the light confined within the fibre, allowing it to travel long distances with minimal signal loss.

Furthermore, the use of transparent glass (or plastic) for the fibre core ensures that light is not significantly absorbed as it travels through the fibre. This allows for high-speed data transmission with minimal signal degradation, making optical fibres ideal for cable television and high-speed broadband applications.