On the effect of dispersion on nonlinear phase noise
  The variance of nonlinear phase noise is analyzed by including the effect of intrachannel cross-phase modulation (IXPM)-induced nonlinear phase noise. Consistent with Ho and Wang [1] but in contrary to the conclusion of both Kumar [2] and Green et al. [3], the variance of nonlinear phase noise does not decrease much with the increase of chromatic dispersion. The results are consistent with a careful reexamination of both Kumar [2] and Green et al. [3]. 
Keang-Po Ho and Hsi-Cheng Wang