In high-capacity and long-haul optical communication systems, signal distortion is induced by group velocity dispersion and the nonlinearity of optical fibers. Numerous techniques have been proposed to compensate for this distortion. These include dispersion management (DM), the use of an optical phase conjugator (OPC), and a combination of the two. Improvements in system performance have been reported for these combined systems, but the fixed residual dispersion per span (RDPS) often used in such optical links restricts the flexibility of the link configuration. In this study, we investigated the effect of alternating the positive and negative RDPS two fiber spans apart on the compensation of distorted 24 channel × 40Gbps WDM signals in a DM link with a midway OPC. We confirmed that a pattern of alternating positive and negative RDPS was superior to uniform distribution of RDPS across whole spans with a view of compensating the distorted WDM channels.

optical phase conjugation, dispersion management, residual dispersion per span, net residual dispersion, wavelength-division multiplexing.