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. If we have measured gains in linear units (e. in Watts – W), the loss value in dB is calculated by the formula: Loss (dB) = 10 lg ( mW1 / mW2 ) When both gains. An optical splitter, also known as an optical splitter, is a passive component used in PON (Passive Optical Network) networks such as FTTH networks. Its main function is to split an incident light signal into two or more output signals. These are known as passive optical splitters, and they perform the function. In the backbone of modern Fiber-to-the-Home (FTTH) networks, optical splitters serve as the unsung heroes that enable cost-efficient connectivity for millions of subscribers.