Which test equipment determines the loss characteristics throughout a fiber?

The optical time domain reflectometer (OTDR) is the equipment specifically designed for determining the loss characteristics throughout a fiber optic cable. It does this by sending pulses of light through the fiber and measuring the time it takes for the reflections to return. By analyzing the reflections and their intensity, an OTDR can create a profile of the fiber, identifying splice loss, connector loss, and overall attenuation levels along the entire length of the fiber. This capability allows technicians to pinpoint issues and assess the performance of the fiber network effectively.

Other options, while useful in fiber optic testing, serve different purposes. An optical power meter measures the amount of optical power in the fiber but does not provide detailed information on loss characteristics or where those losses occur within the fiber. An optical return loss test set measures the return loss, which is related to reflections at connectors and splices but does not provide a comprehensive view of loss throughout the entire fiber run. A sampling oscilloscope, on the other hand, is primarily used for analyzing signal waveforms rather than optical loss characteristics in fiber. Thus, the OTDR stands out as the most appropriate tool for this specific function.