An analysis of polarize-optical modulation (POM) of the light flow by electro-optical (EO) medium has been performed. POM without aperiodic transformation and with the transformation of the spectrum was reviewed. It was shown that the electro-optical modulation occured with the transformation of the spectrum. The dependence of the contrast ratio POM of the width of the emission spectrum in the case of one EO medium and the optical transmission of the modulated radiation POM for the two EO mediums were obtained.