An apparatus for mitigating polarization dependent loss (PDL) in an optical signal-to-noise ratio (OSNR) of a modulated optical signal is disclosed. The apparatus may comprise a spectrum analyzer to measure an optical power spectrum of a modulated optical signal. The apparatus may also comprise a measuring unit to select a first portion of the modulated optical signal and a second portion of the modulated optical signal, where each of the first and second portions of the modulated optical signals may include an independent noise distribution indicative of PDL, and measure a time-varying parameter of the first and second portions. The apparatus may also include a signal processor to PDL in an OSNR by transforming any elliptical polarization associated with the independent noise distribution into a ball polarization, determining a correlation between time-varying parameters of the first and second portions, and calculating a PDL mitigated OSNR.