Question

Which type of optical fiber is best suited for long-distance communication because of its low attenuation?

• A. Multimode step-index fiber
• B. Multimode graded-index fiber
• C. Single-mode fiber
• D. Plastic optical fiber

Hint:

Need to go the distance? Use single-mode fiber — fewer paths, less loss, better performance!

Answer 1

The Correct Option is C

In optical communication, attenuation refers to the loss of signal strength as light travels through the fiber. For long-distance communication, minimizing this loss is crucial to maintaining signal clarity and transmission efficiency.
Single-mode fibers are designed to allow only one mode (path) of light to propagate through the core. This reduces modal dispersion — a major cause of signal spreading and distortion in multimode fibers — and results in significantly lower attenuation. As a result, single-mode fibers are ideal for high-speed, long-distance data transmission such as in internet backbones and telecommunication networks.
Why the other options are less suitable:

• (A) Multimode step-index fiber: Suffer from high modal dispersion and attenuation, limiting distance.
• (B) Multimode graded-index fiber: Better than step-index but still not optimal for long-range use.
• (D) Plastic optical fiber: Inexpensive and flexible but has high attenuation, making it suitable only for short-range applications.

Therefore, for minimal signal loss and long-distance communication, the best choice is the single-mode fiber.