What is the purpose of cladding in a fiber optic cable?

What is the purpose of cladding in a fiber optic cable?

• A. To guide the light down the fiber.
• B. To protect the core from moisture.
• C. To convert light into electrical signals.
• D. To increase fiber thickness.

Answer: (A)

Cladding keeps the light confined in the fiber by surrounding the core with material that has a lower refractive index. This difference causes total internal reflection at the core–cladding boundary, so light stays inside the core as it travels, even when the fiber bends. That’s what allows light to be guided efficiently along the fiber. It isn’t primarily about moisture protection, converting light to electrical signals, or increasing the fiber’s thickness.

Cladding keeps the light confined in the fiber by surrounding the core with material that has a lower refractive index. This difference causes total internal reflection at the core–cladding boundary, so light stays inside the core as it travels, even when the fiber bends. That’s what allows light to be guided efficiently along the fiber. It isn’t primarily about moisture protection, converting light to electrical signals, or increasing the fiber’s thickness.