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.

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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.