Power threshold due to parametric gain in dispersion-mapped communication systems

Parametric gain (PG) is investigated in conventional terrestrial transmission systems at 10 Gb/s. The authors present new results that show how at large signal transmitted power the PG effect strongly differs from the predictions of the standard small-signal approach, which neglects the noise quadratic and higher order terms in the nonlinear Schrodinger equation. The authors give a new explicit expression of the maximum transmittable power in a dispersion-mapped transmission system impaired by PG and show that such power threshold is due to the inflation of the low frequency portion of the in-phase noise spectrum.