What is optical fibre in physics?

Optical fibre is a thin, flexible strand of glass or plastic that transmits light from one end to the other. In physics, it works mainly on the principle of total internal reflection, which keeps the light trapped inside the fibre as it travels.

Quick Scoop

An optical fibre has a core and a cladding. The core has a higher refractive index than the cladding, so light that enters at the right angle keeps bouncing along the core instead of escaping.

How it works

• Light is sent into one end of the fibre.
• It reflects repeatedly inside the core because of total internal reflection.
• That lets light travel long distances with very little loss.
• Because it uses light, it can carry information very quickly.

Why it matters

• It is used in internet and telecom cables.
• It reduces signal loss compared with metal wires.
• It is immune to electromagnetic interference.
• It is also used in medical instruments and sensors.

In one line

Optical fibre is a light-guiding medium that uses total internal reflection to carry signals efficiently over long distances.

TL;DR: Optical fibre is a glass or plastic wire-like medium that carries light signals by total internal reflection, making it fast and efficient for communication.