Most failures tend to be in the OSP, and are caused by improper installations which can be caused by microbends, splices, connector damage, and improper fiber management. Splitter failures can also be intrinsic, which we'll address. Fiber optic splitters distribute optical power from one input fiber to multiple output fibers through either fused biconical taper (FBT) coupling or planar lightwave circuit (PLC) waveguide structures. Their performance depends on optical symmetry, waveguide integrity, and mechanical stability of. Optical splitters in the outside plant (OSP) are used mostly in passive optical networks (PONs) for fiber-to-the-user (FTTx) networks, and are often overlooked as failure points. In this article I focus on a few basics of optical splitters, their applications, typical causes of failures, and how to. 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. The split ratio and insertion loss are two key parameters defining their performance. Splitter loss is a natural consequence of splitting the light signal, where the signal is attenuated, resulting in a lower power level in the output fibers. When light travels through these splitters, some signal strength is inevitably lost.