Comparison of EDFA and LRA preamplifier performance in WDM transmission systems

The main goal of this paper is to investigate and compare the performance of an erbium-doped fiber amplifier and a lumped Raman amplifier when they are used as preamplifiers. For this purpose a simulation model of a 8 channel 10 Gbps dense wavelength division multiplexed transmission system with non-return-to-zero intensity on-off keying modulation, 100 GHz channel spacing and a discrete preamplifier was introduced. While choosing the configuration of the preamplifiers the authors configure the wavelength and the power of the pumping radiation in both cases by observing the obtained gain spectra and noise figure values. The main criteria for choosing the parameters of the pumping radiation was to find the minimal pumping power that would ensure that the bit-error-ratio values in all channels stay below the 10^-12 threshold.