Fiber optical parametric amplifiers (FOPA) are well known for the variety of potential applications in all-optical signal processing. Many of these applications use the idler spectral components that are produced by the four wave mixing parametric process. The performance of parametric amplifiers and, therefore, also of generation of idler spectral components, is highly dependent on different factors, including stimulated Brillouin scattering (SBS) and polarization of the input signal. The aim of this article is to investigate the influence of pump phase modulation of parametric amplifiers, used for SBS mitigation, and the impact of mutual state of polarization mismatch of the input signal and the pump on the generation of idler spectral components. The obtained results have shown that it is crucial for systems with FOPAs to ensure that the input signal and the pump are co-polarised, as polarization dependant gain of 16.7 dB and 33.5 dB difference in idler generation was observed in the performed simulations. It was also found that applying the phase-modulation of the pump for SBS mitigation has caused 54% idler spectral broadening. Therefore additional measures must be taken to avoid inter-channel crosstalk among the neighbour channels.