Example: A 1×2 uneven splitter might allocate 70% of power to its cascade port and share the remaining 30% among four local ports. Cascade Chains: You can chain several uneven. So how to calculate the optical attenuation of the optical splitter? Optical attenuation value of optical splitter = transmit optical power + additional loss + insertion loss + bare fiber loss. Excess loss accounts for manufacturing imperfections, typically 0. If we have measured gains in linear units (e. Every time you double the ports, you double the signal paths — and the theoretical loss grows by about 3 dB. Enter the number of outputs and the excess loss from your splitter datasheet to see the total. In passive optical networks (PON), splitters distribute light from a single fiber to multiple users. You may be confused about how Even Splitting and Uneven Splitting differ—or which one to choose for your network.