Fibre Optics

Optical Fibres utilise total internal reflection at the boundaries of the fibre to carry information digitally in the form of light. The diagram below shows a straight section of optical fibre, but the cable can bend and the light will continue to travel down the fibre, as long as the critical angle is achieved.

fibre optics

The cables can be clad in a material of a lower refractive index than the core, and this lowers the critical angle.

Examples of optical fibre usage: communications for phone lines, and medicine for endoscopy.