Physics 2003 JAMB Past Questions - Question 29: The operation of an optical fibre is based on the principle of

Correct Answer

C

Explanation

The operation of an optical fiber is based on the principle of total internal reflection. Optical fibers are thin, flexible strands of glass or plastic that can transmit light signals over long distances. They work on the principle that when light enters the core of the fiber at a certain angle and encounters the boundary with the cladding (the outer layer of the fiber), it can undergo total internal reflection.

Here's how it works:

1. Total Internal Reflection: When light traveling through the core of the optical fiber strikes the core-cladding boundary at an angle greater than the critical angle, it undergoes total internal reflection. The critical angle is determined by the refractive indices of the core and cladding materials.

2. Repeated Reflection: The light, instead of escaping through the cladding, reflects off the core-cladding boundary and continues to travel down the length of the fiber. This process of reflection occurs as the light waves bounce off the boundary in a zigzag pattern.

3. Multiple Modes: Optical fibers can support multiple modes or paths for light propagation, depending on their design. Single-mode fibers allow only one mode of propagation, while multi-mode fibers permit multiple modes. The choice of fiber type depends on the specific application and required performance.

4. Low Signal Loss: Because of total internal reflection, the light signal can travel through the fiber with very little signal loss over long distances. This is in contrast to traditional electrical transmission, where signal attenuation and interference can be significant over long cable lengths.

Optical fibers are widely used in telecommunications, data transmission, and various other applications where high-speed, high-capacity data transmission is required, as they offer advantages such as low signal loss, immunity to electromagnetic interference, and high bandwidth.