The performance of an all-optical regenerator utilizing self-phase modulation in a highly nonlinear fiber and offset optical filtering is assessed using computer simulation. By varying the bandwidth and offset of the optical filter, the Q-factor performance of the regenerator is near-optimized for systems impaired by ASE noise and systems impaired by both residual dispersion and ASE noise. Generally, the near-optimum bandwidth and offset of the optical filter differs for these two types of systems. It is found that the selection of the bandwidth and offset is more stringent for systems with ASE noise only. For systems with residual dispersion and ASE noise, the selection of the filter bandwidth and offset depends on the amount of residual dispersion with quite different trends being observed. The regenerator is more effective when the residual dispersion is negative.