Attenuation in fiber optics is the gradual loss of light signal strength as it travels through a fiber cable. This can be due to a variety of factors: scattering and absorption, intrinsic loss, extrinsic loss, bending losses and more. If you don't know what kind of losses to expect in your system, you won't know how many other components. The uses various types of network cables, including multimode and single-mode fiber-optic cable. This section specifies requirements for telecommunications optical fiber backbone cabling. VA Infrastructure Standard for. Optical Signal Attenuation is the single greatest factor limiting the distance and performance of your network. dBm difference: A(dB) = Pin(dBm) − Pout(dBm). Select a mode that matches your task.