Question

In optical fibers, the principle that enables light transmission along the fiber's length is:

• A. Refraction
• B. Total internal reflection
• C. Diffraction
• D. Polarization

Hint:

Think of optical fibers as light traps — light keeps bouncing inside the core thanks to total internal reflection!

Answer 1

The Correct Option is B

Optical fibers are widely used in telecommunications to transmit data using light. The fundamental principle that allows light to travel through these fibers over long distances without escaping is total internal reflection.
When light travels from a denser medium (like the core of the optical fiber) to a less dense medium (the cladding), it bends away from the normal. If the angle of incidence is greater than a certain critical angle, the light reflects entirely within the core instead of refracting out — this is total internal reflection.
Key Points:

• Total internal reflection requires:
  • The core to have a higher refractive index than the cladding.
  • The light to strike the core-cladding boundary at an angle greater than the critical angle.
• This principle keeps the light trapped inside the core, guiding it through long distances with minimal loss.

Why Other Options Are Incorrect:

• Refraction explains bending of light at interfaces but not confinement.
• Diffraction is spreading of waves around obstacles and is not used to guide light in fibers.
• Polarization deals with the direction of light's electric field but doesn't affect transmission mechanism.

Hence, the principle that enables efficient light transmission in optical fibers is total internal reflection.