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. Further analysis reveals that high-performing random dispersion maps tend to resemble a half-cycle sinusoidal profile, characterized by positive accumulated dispersion before the OPC and negative accumulated dispersion after the OPC. These findings indicate that partial structural regularity within random dispersion plays a key role in enhancing OPC-based compensation. This study provides practical design guidelines for dispersion-managed optical transmission systems under realistic constraints and suggests that guiding random dispersion distributions toward favorable structures can improve system robustness and flexibility.