Which type of optical amplifier does not introduce detectable distortion to the modulated light wave?

The choice of an EDFA, or Erbium-Doped Fiber Amplifier, as the correct answer reflects its unique properties in maintaining the integrity of modulated light waves during amplification. EDFAs are known for their ability to amplify optical signals over long distances without introducing significant noise or distortion. This is largely due to the material composition and the operational mechanism of the amplifier, which does not interact with the phase or the modulation format of the incoming light.

When using an EDFA, the amplification process occurs in an erbium-doped fiber where the signal is amplified by stimulated emission. This process efficiently boosts signal strength while preserving the original signal's characteristics, making EDFAs especially suitable for long-haul fiber optic communication systems. Because they do not distort the modulated waveform, they enable high-fidelity transmission, which is critically important for maintaining data integrity over extensive communication networks.

Other types of amplifiers, while useful in certain applications, can introduce various forms of distortion or noise. For example, gain-switched and semiconductor amplifiers can potentially distort the signal characteristics due to their operational principles. Raman amplifiers, while effective for certain applications, can also introduce nonlinear effects that may affect signal quality. Hence, the selective capabilities of the EDFA make it the