Effects of intermodulation distortions due to the joint action of dynamic chirping and "dispersive" transmission of SCM optical signals

The effect of the joint action of the AM-FM conversion due to chirping in a semiconductor laser and the chromatic dispersion of the optical fiber has been so far analyzed in the case of static chirping in hybrid multichannel AM/QAM optical fiber transmission systems, based on subcarrier-multiplexing (SCM) technique. The static approach is not exhaustive in the case of channeling covering the whole bandwidth, that is /spl ap/1 GHz, for which the dynamic chirping must be considered, as well. In this letter, analytical expressions of the power spectral density of the intermodulation distortions due to "dispersive" transmission of chirped intensity-modulated signals are calculated, considering both the static and the dynamic effects. As a consequence of this analysis, an accurate method for the determination of the small-signal photon decay rate /spl Gamma//sub P/ of the semiconductor laser is proposed, which is based on electrical measurements of the second-order intermodulation products.