What do optical power meters evaluate in a fiber-optic system?

Optical power meters are crucial tools in fiber-optic systems, primarily used to measure the overall loss of an optical fiber. This loss can occur due to various factors, including scattering, absorption, and connector losses. By quantifying the amount of light that is transmitted through the fiber versus what is received at the end, optical power meters help technicians assess the performance of the fiber-optic link. This measurement is essential for ensuring that the system operates within the specified parameters and that signal integrity is maintained.

In contrast, while other options may relate to aspects of fiber optics, they do not accurately describe the primary function of an optical power meter. Factors like the total length of the fiber and the gain of optical signals are relevant in a broader context of fiber-optic communication but are not directly evaluated by optical power meters. Input power to the transmitter is another important consideration in the overall system design, but measuring the loss within the fiber itself provides more critical insight into the health and efficiency of the communication pathway. Therefore, option C accurately reflects the intended purpose of optical power meters within fiber-optic systems.