Optical splitters introduce a large attenuation, a 1:2 splitter introduces as much attenuation as an optical fiber about 10 km long (>3dB). The existence of an optical splitter on the display of OTDR shows as a large drop. The split ratio and insertion loss are two key parameters defining their performance. 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. Understanding the types of splitters, their impact on network performance, and how to measure their losses ensures high-quality network operation and facilitates optimal splitter selection based on.