Effect of residual dispersion in the phase-conjugation fiber on dispersion compensation in optical communication systems

A simple analytic formula is obtained for calculating the output pulse shape and spectrum in a dispersion-compensation system where the midway optical phase conjugation (OPC) is realized by nondegenerate four-wave mixing in a dispersion-shifted fiber. The nonlinearity and residual dispersion of the OPC fiber are included in our model, and their effects on the OPC process are discussed. The third-order dispersion in the OPC fiber contributes to the total third-order dispersion of the system while the second-order dispersion (group velocity dispersion) and fourth-order dispersion introduce spectral filtering. The design issues such as the bandwidth limits of the input signal, maximum frequency spacing between the signal and the pump, and optimal location of the OPC fiber are discussed.<>