As the signal propagates through a fiber optical communication system it suffers from attenuation and dispersion. Attenuation determines the repeater less separation between a transmitter and a receiver, while dispersion causes the signal pulses to broaden as they travel along the fiber. In other words attenuation is the process of weakening of a signal as it propagates through a fiber and dispersion limits the information carrying capacity. Either repeaters or optical amplifiers may compensate these losses. Due to pulse broadening two neighboring pulses interfere with each other and information in the pulses gets overlapped. This can be attributed to many factors. One of the basic reasons is the non-linear property of the fiber. These effects are not effective at low power intensity, but degrade the signal at high power levels. Before 1960 LED’s were main source of optical communication, which operate at a low power level. With the advent of highly coherent laser beams the electric... Это и многое другое вы найдете в книге SPM Reduction In Fiber Using EDFA (Pardeep Kumar Jindal)