A method and apparatus for reducing nonlinear phase noise that is induced in
an
optical transmission system by the interaction of optical amplifier noise and Kerr
effect. The apparatus includes an intensity-scaled nonlinear phase noise compensator.
The phase noise compensator reduces the nonlinear phase noise by rotating a phase
estimate by a scaled signal strength estimate for the optical signal or by comparing
a complex estimate to curved regions having scaled nonlinear decision boundaries.
The scale factor is derived from the number of spans in the transmission system.
Another embodiment of the phase noise compensator uses the scaled signal strength
for re-modulating an optical signal.
