Dependency of cross-phase and self-phase modulation on different link parameters for a multispan WDM system

An analytical approach to determine absolute power transfer due to cross-phase modulation (XPM) and self-phase modulation (SPM) from their spectral characteristics in a multispan intensity-modulation direct-detection (IM-DD) optical system is presented in this paper. Here, dependency of XPM and SPM power transfer on different link parameters like pump power, channel spacing, link length and, bitrate of interacting channels is the focus of our investigation. It is reported that, beyond a certain input power, XPM and SPM induced crosstalk increases rapidly and, thus, limits the allowable transmitting power. XPM and SPM induced power transfer per unit probe power is found posses an approximately linear relation with fiber length. XPM crosstalk between channels of different data-rate is also evaluated. These crosstalks are reported to be increasing for higher wavelength channels to worsen their performance. To compensate for XPM and SPM induced crosstalk, the usage of short period dispersion managed fiber (SPDMF) is found to be very effectual for the improvement of the above mentioned phenomena.