Manufacturers provide a fiber loss factor in dB per kilometer. 25 dB/km (@1550nm). Fiber Loss Factor: Fiber loss holds significant sway over system performance. Fiber Type: Single-mode fibers have a loss. It is calculated by adding the estimated average losses of all the components used in the cable plant to get the estimated total end-to-end loss. The loss budget has two uses, 1) during the design stage it is used to ensure the cabling being designed will work with the links intended to be used. This page describes the Fiber Loss Margin calculator. Add each MUX or DEMUX on the path. Total Fiber Loss = Fiber Length × Attenuation Coefficient Total Connector Loss = Number of Connectors × Loss per Connector Total Splice Loss = Number of Splices × Loss per Splice Total Link Loss = Fiber Loss + Connector Loss + Splice Loss +. After measuring the loss of a fiber link, you now have to determine if that fiber link loss is acceptable or not.