Attenuation describes the continuous loss along the fiber, while insertion loss describes the additional loss caused by components such as connectors, splices, or splitters. They directly influence the optical budget in FTTH, ODN, 5G fronthaul, and data center networks. A passive optical splitter divides an incoming light signal across two or more output ports. In fiber optic networks, particularly in FTTx (Fiber to the x) and PON (Passive Optical Networks) deployments, splitters play a central role in distributing the optical signal from a single source to multiple destinations. Excess loss accounts for manufacturing imperfections, typically 0. Review attenuation, splice, connector, and splitter effects.