Design and simulation of long-haul 32 × 40 Gb/s Duobinary DWDM link in the presence of non-linearity with under-compensated dispersion

In this paper, we present a simulation based analysis of long haul 40 Gb/s Dense Wavelength Division Multiplexing (DWDM) system operating at 1.28 Tb/s with Duobinary Return-to-Zero (DRZ) modulation format. The 32 Channels DWDM system has been numerically compared for pre, post and symmetrical dispersion compensation schemes with 50 GHz channel separation to characterize this modulation format for 40 Gb/s data rate. The transmission link is designed first with perfect compensation and then with under-compensation. The performance has been evaluated using Q value as the major parameter, by varying the input power for different transmission distances with different dispersion compensation schemes. It is observed that even under four-wave mixing(FWM) degradation, DRZ based DWDM system shows acceptable performance beyond 1000 Km. This paper reports the superiority of DRZ format over the conventional NRZ /RZ schemes in both cases.