What is the function of a pre-amplifier in an optical network?

What is the function of a pre-amplifier in an optical network?
A . Through the pre-amplifier, the optical signal is amplified at the receiver side after it travels along the fiber from another node.
B. Through the pre-amplifier, the optical signal is amplified at the transmitter side before it is sent to the line span.
C. Through the pre-amplifier, the optical signal is amplified both the receiver side and at the transmitter side.
D. Through the pre-amplifier, the optical signal is amplified within the node internally to recover internal losses due, for instance, to cascaded filters.

View Answer

Answer: B

Explanation:

A pre-amplifier is an optical amplifier that is used to boost the power of the received optical signal before it is detected by the receiver in an optical communication system. This is done to overcome the loss of power that occurs as the signal travels through the optical fiber and to ensure that the receiver can detect the signal. The pre-amplification stage is typically located close to the receiver in order to minimize the distance that the signal has to travel between the amplifier and the receiver, which helps to reduce the noise and distortion in the signal.