Optical budget inputs
Model the ODN with configurable assumptions or the actual splitter insertion loss.
Check the complete optical operating window
GPON optical path-loss classes define operating ranges, not only maximum loss. B+ uses 13–28 dB and C+ uses 17–32 dB references. The final design must also respect the actual transmitter power, receiver sensitivity and receiver overload of the selected equipment.
Ideal division loss is not real insertion loss
10·log10(N) represents ideal power division for a 1:N splitter. Real splitters also have excess loss, connector effects and manufacturing tolerances. For final engineering, use the actual insertion-loss specification whenever possible.
Receiver margin and engineering reserve are different
Margin above sensitivity shows how far estimated RX is above the configured sensitivity. Margin after design reserve additionally subtracts the engineering reserve requested by the designer. This distinguishes a link that merely reaches sensitivity from one that also preserves operational headroom.
Use equipment and passive-component datasheets
Transmit power, receiver sensitivity, overload, fiber attenuation, connector loss, splice loss and splitter insertion loss depend on the actual design. Treat this result as an engineering planning calculation and validate the final ODN with vendor specifications and field measurements.