Advanced modulation formats and receiver filtering analysis of optical WDM systems with optimized distributed Raman amplifiers

This paper presents a systemic simulation analysis to find the maximum reach of an optical WDM distributed Raman amplified system evaluated in the following scenario: three different channel loads located at the C-Band, advanced modulation formats for 46 and 112 Gb/s data rates, chromatic dispersion compensation across the span and signal re-amplification carried out through optimized distributed Raman amplifiers (DRAs), in three distinct amplifiers configurations. The 46 Gb/s NRZ/DQPSK and 112 Gb/s NRZ/DPQPSK modulation formats show superior performances as well as insensitiveness to the filtering effects. The worst channel Q-Factor after the band pass filters is 3.09 which corresponds to an uncorrected BER threshold of 10^-3 for the 12% overhead FEC used.