Mid-span compensation of nonlinear phase noise

The nonlinear phase noise, often called the Gordon-Mollenauer effect, is correlated with the intensity of the optical signal. With a single linear compensator, the optimal location is not preceding the receiver but located at about 2/3 of the fiber link. When N compensators are approximately optimally placed, the standard deviation of nonlinear phase noise is reduced by a factor of 2N + 1. The optimal compensation factors are all approximately equal to each other.