Nonlinear distortions due to the "dispersive" transmission of SCM optical signals in the presence of chirping effect: an accurate analysis

In hybrid multichannel amplitude modulation-quadrature amplitude modulation (AM/QAM) optical fiber transmission systems based on subcarrier-multiplexing (SCM) technique, the performance is affected by the joint action of the AM-FM conversion due to the chirping effect in semiconductor laser and the chromatic dispersion of the optical fiber. In this letter, analytical expressions of the power spectral density of the nonlinearity distortions due to "dispersive" transmission of chirped intensity-modulated signals are calculated, assuming that the message modulating the semiconductor laser is a Gaussian process.