Quick answer: Industry acceptance threshold for a single fusion splice is 0. The question is how much is too much. 05 dB for single-mode fibre and slightly higher for multimode fibre. However, various factors, such as fibre cleanliness, core. The estimate, called a "loss budget" is calculated using typical component losses for each part of the cable plant - the fiber, splices and/or connectors. If the measured loss exceed the calculated loss by a significant amount (remembering the inherent uncertainty in all measurements), the system. Acceptable splice loss in optical fiber is typically considered to be less than 0. 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.