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. The primary contributors to measured splice loss are fiber material and design factors that. 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. Results from a National Electronics Manufacturing Initiative (NEMI) project, formed to improve aspects of fiber optic fusion splicing, are reported.