Compensation of Distorted DWDM Signals by Non-Midway Optical Phase Conjugator in Dispersion-Managed Link Configured with Random-Distributed RDPS

This paper presents a numerical investigation of dispersion-managed dense wavelength division multiplexing (DWDM) transmission systems incorporating a non-midway optical phase conjugator (OPC) under randomly distributed residual dispersion per span (RDPS). Unlike conventional studies assuming ideal symmetric configurations, this work considers more realistic scenarios with asymmetric OPC placement and random dispersion distribution. To ensure the reliability of the analysis, simulations were performed for 100 different random RDPS patterns. A 960 Gb/s DWDM system consisting of 24 channels operating at 40 Gb/s was modeled using the nonlinear Schrödinger equation solved by the split-step Fourier method. To analyze the impact of OPC location, two asymmetric configurations (23-27 and 27-23), were compared. System performance was evaluated using eye-opening penalty (EOP) and timing jitter (TJ). The results show that OPC location has a significant impact on compensation efficiency, with the 27-23 configuration providing overall better performance than the 23-27 configuration. Although randomly distributed RDPS does not always outperform uniform or deterministic dispersion maps, certain random patterns achieve comparable or even superior compensation performance. Through extensive statistical evaluation across five independent random seeds, including Pearson correlation and regression analysis, we observed consistent structural tendencies in the RDPS distribution that enhance compensation efficacy. Specifically, in the 23-27 structure, a high correlation with a ‘half-cycle sin’ profile was preliminarily observed to be beneficial, whereas the 27-23 structure showed sensitivity to both ‘half-cycle sin’ and ‘one-cycle sin’ profiles. These findings suggest that maintaining antipodal-symmetry, even in stochastic environments, provides a stable probabilistic advantage for signal compensation. While we advise a cautious interpretation regarding the universal applicability of these results, the study offers valuable design insights and is expected to facilitate greater flexibility in the design of future high-capacity optical networks.