  Nonlinear phase noise, often called the Gordon-Mollenauer effect, can be
compensated electronically by subtracting from the received phase a correction
proportional to the received intensity. The optimal scaling factor is derived
analytically and found to be approximately equal to half of the ratio of mean
nonlinear phase noise and the mean received intensity. Using optimal
compensation, the standard deviation of residual phase noise is halved,
doubling the transmission distance in systems limited by nonlinear phase noise.
