In this study, single-pass (SP), double-pass (DP), and double pass with passive erbium doped fiber (EDF) configurations are designed as erbium-doped fiber amplifier (EDFA). All configurations have been experimentally investigated for four different EDF. EDFA configurations are simulated at the fixed pump and signal power, pump wavelength and channel numbers. In simulation, EDF length of each fiber optimized for maximum gain and minimum gain ripple. After then, output spectrums are examined for each system. As a result, the gain is low level in the SP-EDFA configuration, despite the improvement of the gain factor with the DP-EDFA scheme, the amplified spontaneous emission (ASE) power adversely affected the noise figure because it propagates both forward and backward along the fiber. The best gain and noise values have been observed in the double pass with passive EDF system.