Is there life beyond the principal states of polarization?

In this paper we show that it is possible to describe exactly the field intensity distorted by polarization mode dispersion (PMD) at the output of a single-mode fiber, without resorting to the principal states of polarization (PSPs). Such description is based on the eigenmodes of what we call the extracted matrices, for which we establish relationships with the PSPs, e.g., by showing their alignment with the PSPs when these are not depolarized over the signal bandwidth.We also show that the eigenmodes of the extracted matrices are less depolarized than the PSPs, and are thus the most convenient frame of reference to express the output field and intensity for high bit rate transmitted signals. We thoroughly investigate the properties of a recently introduced fiber model, which we refer to as the rotation model, based on the rotation of the extracted eigenmodes, which extends the intuition of Bruyère’s PSPs rotation model (1996) to the most stable frame of reference, and hence is expected to give the most accurate description of the PMD fiber for large bandwidth signals. We finally provide a novel eye closure penalty (ECP) formula based on the extracted eigenmodes, and show its relation with the currently available ECP formulas. The accuracy of the novel ECP formula is tested against simulation results of transmission through a fiber synthesized by the rotation model.