Optical attenuation value of optical splitter = transmit optical power + additional loss + insertion loss + bare fiber loss. A splitter does not “create” power; it divides available optical energy among outputs, so every branch must be checked for adequate loss budget. Whether an optical splitter is combining signals in the upstream direction or dividing signals in the downstream direction, it still introduces the same attenuation to an optical. Fiber type + wavelength + length → expected attenuation. 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. Calculate insertion loss for passive optical splitters in PON and distribution networks. Excess loss accounts for manufacturing imperfections, typically 0.