What type of OTDR trace results from fusion splicing two fiber strands with dissimilar cores?

When two fiber strands with dissimilar cores are fusion spliced, the resulting OTDR (Optical Time Domain Reflectometer) trace typically exhibits a gain and loss signature. This occurs because the fibers have different refractive indices and core diameters, which can cause mismatches in the light transmission between the two fibers.

As a result of this mismatch, there will be variations in the signal strength observed in the OTDR trace. The "gain" in the trace can indicate where the light is being transmitted effectively, while the "loss" can indicate sections of the splice where signal degradation occurs due to reflection or scattering caused by the dissimilar properties of the fibers.

This characteristic signature is critical for technicians to assess the quality of the splice and understand how the fiber connection will perform under operational conditions. Recognizing such a signature allows for diagnostics and potential troubleshooting to ensure optimal performance of the fiber optic system.