Which of the following is not a part of a fiber optic data link?

The correct choice highlights that a modulator is not typically considered a part of a fiber optic data link. A fiber optic data link primarily consists of a transmitter, optical fiber, and receiver.

The transmitter converts electrical signals into optical signals, which are then sent through the optical fiber. The optical fiber acts as the medium, transmitting these light signals over distances with minimal loss. Finally, the receiver converts the optical signals back into electrical signals for interpretation and use within the receiving system.

While modulators can indeed play a role in signal processing and can be associated with some advanced fiber optic systems, they are not standard components of the basic fiber optic data link structure. Thus, identifying a modulator as not part of the core components of a typical fiber optic data link is accurate.