What role does backscatter play in OTDR measurements?

Backscatter plays a crucial role in Optical Time Domain Reflectometer (OTDR) measurements primarily by providing information about the loss in the fiber. In an OTDR, a pulse of light is sent down the fiber, and some of the light is scattered back toward the source due to inhomogeneities in the fiber material and any splice or connector points. This scattered light, known as backscatter, allows the OTDR to measure the intensity of the light that returns and enables the calculation of loss at various points along the fiber link.

The OTDR analyzes the time it takes for the backscattered light to return, which gives details about distance. By measuring the amount of backscatter, the instrument can determine the loss characteristics at different fiber sections. Any significant decrease in the backscattered signal can indicate a fault or a high-loss section in the fiber, allowing for maintenance and troubleshooting.

In contrast, options indicating an increase in signal strength, irrelevance to measurements, or preventing reflections do not accurately represent the function of backscatter in this context, as they misinterpret the key principle of how OTDRs utilize backscatter to assess fiber health and performance.