1. A method for automatically modifying a received version of an optical signal to compensate for the effects of polarization mode dispersion (PMD) inflicted upon said optical signal as it transits a transport link from a transmitter to a receiver, the method comprising the steps of: determining digital representations of E x′ and E y′ , E x′ and E y′ being a pair of orthogonal polarization components of said version of said optical signal as received at said receiver, E x′ being along an x′ axis and E y′ being along a y′ axis; effectively dividing said transport link into M virtual PMD segments, M greater than or equal to 1; determining generic polarization components of said optical signal, E x and E y , by calculating [ E x E y ] = ∏ i = 1 M ( PMD i ) - 1 · R 2 - 1 · P - 1 [ E x ′ E y ′ ] , where P is a phase-delay matrix representing additional phase delay between E x′ and E y′ after they are split in said receiver, R 2 is a rotation matrix associated with the angular difference between the primary state of polarization (PSP) axes of the virtual segment closest to said receiver and said x′-y′ axes, and PMD i is a matrix describing the PMD effect of an i-th one of said virtual PMD segments, i=1 to M, and −1 indicates the standard matrix inverse operation.