1 The propagation of a pulse through an optical fiber with randomly varying anisotropy is usually addressed in the context of the Polarization Mode Dispersion (PMD). PMD is signal broadening caused by inhomogeneity of the medium birefringence. In the linear case, the study of PMD was pioneered by Poole [1], who showed that the pulse broadens as the two principal states of polarization split under the action of the random birefringence (see also [2]). Mollenauer et al. have numerically studied a nonlinear model of birefringent disorder in [3], where it was shown that a soliton, launched into the birefringent fiber, does not split, but it does undergo spreading [3] (see also [4]). In this letter, we develop an analytical approach and confirm that a single soliton does degrade due to disorder in the birefringence. The degradation is observable once the soliton traverses the distance z degr ~ D -1 , where D stands for the strength of the noise in the birefringence, measured in units of the soliton width and period ( D Ӷ 1 is assumed, the typical case for telecommunication fibers).The major finding of this letter is a new phenomenon which occurs on scales much shorter than z degr . We report that the interaction between solitons induced by their combined radiation (generated by disorder) is an important factor affecting the soliton dynamics. Initially stationary solitons experience a relative acceleration, ~ D . The intersoliton separation changes on the order of the soliton width at z int ~ 1/ Ӷ z degr . We use and generalize here an approach developed previously to describe solitons interacting in an isotropic medium with fluctuating dispersion [5]. The soliton interaction, in the case of [5], decays algebraically. By contrast, in the anisotropic case discussed in this letter, the interaction is separation-independent. The reason is that, in 1 This work was submitted by the authors in English. D this case, a different type of wave scatters from the solitons. In the isotropic case, the scattering of the radiated waves, emitted by a soliton, by another soliton is not refracted. In the anisotropic case, radiation from one soliton pushes (literally) the other soliton, because the scattering potential is not transparent.Let us briefly formulate the problem. The electric field E , corresponding to a wave packet carrying frequency ω , can be decomposed into complex components E = 2Re[ E ω exp( ik 0 z -i ω t )], where z is the coordinate along the fiber. Concomitant averaging over fast oscillations and over the structure of fundamental mode (a monomode regime is assumed) constitutes the coarse-grained description for the signal envelope described by the two-component complex field Ψ α , = Ψ 1 ( z ) e 1 + Ψ 2 ( z ) e 2 , where e 1, 2 are unit vectors orthogonal to each other and to the waveguide direction. The averaging results in the envelope equation [6,7] (1) Here, the wave packet is subjected to dispersion in retarded time t and to the Kerr nonlinearity, which is described by the last two terms on the left-hand side of ...