Which statement is true regarding additional optical attenuation?

The statement that it can be obtained by the use of an in-line optical attenuator is correct. In-line optical attenuators are devices specifically designed to deliberately reduce the power level of an optical signal traveling through a fiber optic system. This reduction in signal power is referred to as optical attenuation and is particularly useful in applications where signal levels need to be adjusted to meet certain performance criteria or to prevent saturation of receiving equipment.

In the context of performance testing, managing optical attenuation is crucial to ensuring that signals are not too strong or too weak for effective communication. This adjustment can be vital for optimizing the performance of fiber optic systems, making the use of optical attenuators a practical solution in many scenarios.