Which modulation technique changes the amplitude of light waves in relation to an incoming signal?

The correct answer is amplitude modulation because this technique specifically involves varying the amplitude of a carrier signal, in this case, light waves, in accordance with an incoming signal. In optical fiber communication, amplitude modulation effectively translates the variations in the incoming electrical signal into corresponding variations in light intensity. This modulation allows the information to be transmitted over the fiber by making the light waves stronger or weaker depending on the data signals being sent.

In comparison, frequency modulation alters the frequency of the carrier signal rather than its amplitude. Phase modulation, on the other hand, modifies the phase of the carrier signal and does not affect the amplitude. Pulse modulation utilizes discrete signals and does not directly pertain to continuous amplitude changes related to a particular signal. Understanding the specific changes in amplitude allows for clearer insights into the modulation processes used in fiber optics and their implications for data transmission.