Question

Which optical source is preferred for long-distance, high-speed fiber communication?

• A. LED
• B. Laser diode
• C. Photodiode
• D. LDR

Hint:

Optical communication sources: \[ \boxed{ \begin{aligned} \text{LED} &\rightarrow \text{Short distance, low cost} \text{Laser diode} &\rightarrow \text{Long distance, high speed} \end{aligned} } \]

Answer 1

The Correct Option is B

Step 1: Compare optical sources. Laser diodes produce \[ \begin{aligned} &\bullet\ \text{High optical power}, &\bullet\ \text{Narrow spectral width}, &\bullet\ \text{High modulation speed}. \end{aligned} \] These characteristics make them suitable for long-distance fiber communication.

Step 2: Choose the correct option. Hence, \[ \boxed{\text{Laser diode}} \] is preferred for long-distance, high-speed optical communication. Therefore, \[ \boxed{(B)} \] is the correct answer.