Acceptable splice loss in optical fiber is typically considered to be less than 0. To be able to judge whether a fiber optic cable plant is good, one does a insertion loss test with a light source and power meter and compares that to an estimate of what is a reasonable loss for that cable plant. However, various factors, such as fibre cleanliness, core. Splice loss refers to the part of the optical power that is not transmitted through the splice and is radiated out of the fibre. The total loss in decibels at the fusion splice is given by the following equation, where Pin is the total power incident on the fusion splice and Ptrans is the. The standard for splice loss in optical fiber is typically defined by the International Electrotechnical Commission (IEC) or the Telecommunications Industry Association (TIA).