Attenuation in fiber optics, also known as transmission loss, is the reduction in the intensity of the light signal as it travels through the transmission medium. Attenuation coefficients in fiber optics are usually expressed in units of dB/km. The medium is usually a fiber of silica glass that confines the incident light beam within. Attenuation is an important factor limiting the transmission of a digital signal across large distances. Fiber-optic communication is a form of for from one place to another by sending pulses of or through an. The light is a form of that is to carry information. Fiber is preferred over electrical cabling when high, long distance, or immunity to is required. This type of commu.