Fiber optic used in communication works only on which principle?

Fiber optic used in communication works only on the principle of total internal reflection of light (option D). Inside an optical fiber, light travels through a core made of a material with a high refractive index surrounded by a cladding with a lower refractive index. When light enters the core at a certain angle (above the critical angle), it undergoes total internal reflection at the core-cladding interface. This reflection process traps the light within the core, allowing it to travel long distances without significant loss of signal strength. This principle is crucial for transmitting data as pulses of light, enabling high-speed and reliable communication over optical networks. Unlike regular reflection of light (option A) or diffuse reflection of light (option B), which do not maintain the coherence or intensity needed for optical communication, total internal reflection specifically facilitates the efficient transmission of light signals through optical fibers, making it indispensable in modern telecommunications infrastructure.