Gain Flattening Improvements With Two Cascade Erbium Doped Fiber Amplifiers In WDM Systems

The new optical communication systems utilize WDM technology. The optical amplifiers are one of the most important parts of optical communication networks. These amplifiers have been used at three states of Booster, Pre-amplifier, and In-line by amplifying optical signal. With regard to much expanses of equipment and optical communication systems, the design of amplifiers with higher gain and lower channels gain flattening applys lower equipments. In this article, a WDM system have been designed by two cascade EDFAs with two separate pump lasers, which are equal without gain flattening filter. Then, pump laser power parameter has been considered as the variable and the best fiber length Erbium doped with respect to gain flattening between channels and the highest channels gain and the output noise figure of system.