Suppression of Manakov soliton interference in optical fibers

In this paper, we study the interaction of two vector solitons in the Manakov equations that govern pulse transmission in randomly birefringent fibers. Under the assumptions that these solitons initially are well separated and having nearly the same amplitudes and velocities but arbitrary polarizations, we derive a reduced set of ordinary differential equations for both solitons' parameters. We then solve this reduced system analytically. Our analytical solutions show that, when two Manakov solitons have the same amplitude and phases, their collision distance steadily increases as their initial polarizations change from parallel to orthogonal. In particular, the collision distance at orthogonal polarizations is of the order of the square of the collision distance at parallel polarizations. When the Manakov solitons have different amplitudes, a quasiequidistant bound state can be formed. The degrees of position and amplitude oscillations in this bound state diminish as the initial polarizations change from parallel to orthogonal. With a combination of launching Manakov solitons along orthogonal polarizations and at unequal amplitudes, Manakov-soliton interference is almost completely suppressed. These theoretical results are in excellent agreement with our direct numerical simulations.