We study the quasiclassical dynamics of the cross-Kerr effect. In this approximation, the typical periodical revivals of the decorrelation between the two polarization modes disappear and remain entangled. By mapping the dynamics onto the Poincaré space, we find simple conditions for polarization squeezing. When dissipation is taken into account, the shape of the states in such a space is not considerably modified, but their size is reduced.The optical Kerr effect refers to the intensity-dependent phase shift that a light field experiences during its propagation through a third-order nonlinear medium. This leads to a remarkable non-Gaussian operation that has sparked considerable interest due to potential applications in a variety of areas, such as quantum non-demolition measurements [1-9], generation of quantum superpositions [10][11][12][13][14][15][16][17][18][19], quantum teleportation [20][21][22], quantum logic [23-28] and single-particle detectors [29][30][31], to cite only a few. Enhanced Kerr nonlinearities have been observed in electromagnetically induced transparency [32-35], Bose-Einstein condensates [36], cold atoms [37] and Josephson junctions [38-40]. Additional arrangements involve the Purcell effect [41], Rydberg atoms [42], light-induced Stark shifts [43] and nanomechanical resonators [44].Special mention must be made of the role this cubic nonlinearity has played in the generation of squeezed light. The first proposals employed schemes involving a nonlinear interferometer [45] or degenerate four-wave mixing [46,47]. But quite soon optical fibers became the paradigm for that purpose [48][49][50][51][52][53]. However, due to the typically small values of the nonlinearity in silica glass [54], Kerr-based fibers need long propagation distances and high powers, which bring other unwanted effects [55,56].In this paper, we direct out attention on this limit of high intensities, in which one could expect a classical description to be pertinent. Under reasonable assumptions, Maxwell's equations lead to a set of coupled nonlinear Schrödinger equations that has long been a useful tool for depicting the behavior of optical fields in nonlinear dispersive media. It has proved valuable in the description of such diverse phenomena as pulse compression, dark soliton formation and self-focusing of ultrashort pulses [57]. However, there remain non-classical features that cannot be explained in this classical manner. To put it differently, at the most basic level, the propagation of light in a Kerr medium is accompanied by unavoidable quantum effects.The considerations so far indicate that the regime we wish to explore can be regarded as a problem at the boundary between classical and quantum worlds. Probably, the transition between both can be best scrutinized by exploiting phase-space methods [58][59][60]. This opens New Journal of Physics 15 (2013) 043038 (http://www.njp.org/)