Doubt & Answer Explanation

Answer Explanation

Optical fibres are widely used because signals travel along them with less loss (compared to metal wires) and are also immune to electromagnetic interference. "Loss" here refers to the reduction in the intensity of the signals over time. Electromagnetic interference is the change in the signal being transmitted because of the influence of external electromagnetic waves.

Cladding is one or more layers of material of lower refractive index, in intimate contact with a core material of higher refractive index inside an optical fibre. The cladding causes light to be confined to the core of the fiber by total internal reflection at the boundary between the two media.

The core of a conventional optical fiber is a cylinder of glass or plastic that runs along the fiber's length. The core is surrounded by a medium with a lower index of refraction, typically a cladding of a different glass, or plastic. Light travelling in the core reflects from the core-cladding boundary due to total internal reflection, as long as the angle between the light and the boundary is less than the critical angle.

Thus the core functions as the medium with higher refractive index while cladding functions as the medium with lower refractive index.