Question

In optical fibers, does the core or the cladding have a higher refractive index?

• A. Core
• B. Cladding
• C. Both are equal
• D. It varies randomly

Hint:

Optical fiber principle → Total internal reflection
Core refractive index > Cladding refractive index

Answer 1

The Correct Option is A

Concept:
An optical fiber is a flexible transparent fiber used to transmit light signals over long distances using the principle of total internal reflection.
Step 1:Structure of optical fiber.
An optical fiber consists of three main parts:

• Core
• Cladding
• Protective coating

Step 2:Refractive index relationship.
For total internal reflection to occur, the refractive index of the core must be slightly higher than that of the cladding.
Step 3:Propagation of light.
Because of this difference in refractive index, light entering the core reflects internally at the core–cladding boundary and travels through the fiber with minimal loss. Conclusion:
Therefore, in optical fibers the core has a higher refractive index than the cladding.