The Experimentally Comparison of the Single and Double Pass Erbium Doped Fiber Amplifiers in the C Band

In this study, single and double pass erbium doped fiber amplifiers (edfa) have been experimentally investigated. firstly, gain and noise figure values of single and double pass edfas are measured while input signal power is varied from -40 dbm to +5 dbm at the 1554 nm wavelength. then, measurements are repeated while wavelength values of input signal are varied from 1526 nm to 1570 nm at the -30 dbm signal power. consequently, the gain of double pass edfa is improved by about 3-9 db. however, the noise figure is increased to about 2-5 db due to the amplified spontaneous emission (ase) power propagates both forward and backward along the fiber at the double pass edfa.