Study of EDFA and Raman system transmission reach with 256 Gb/s PM-16QAM signals over three optical fibers with 100 km spans

We compare the transmission performance of three different optical fibers in separate 256 Gb/s PM-16QAM systems amplified with erbium doped fiber amplifiers (EDFAs) and distributed Raman amplification. The span length in each system is 100 km. The fibers studied include standard single-mode fiber, single-mode fiber with ultra-low loss, and ultra-low loss fiber with large effective area. We find that the single-mode fiber with ultra-low loss and the large effective area fiber with ultra-low loss afford reach advantages of up to about 31% and 80%, respectively, over standard fiber measured at distances with 3 dB margin over the forward error correction (FEC) threshold. The Raman amplified systems provide about 50% reach length enhancement over the EDFA systems for all three fibers in the experimental set-up. For the best performing fiber with large effective area and ultra-low loss, the absolute reach lengths with 3 dB margin are greater than 1140 km and 1700 km for the for EDFA and Raman systems, respectively.