SOLITON COLLISIONS IN A MODEL OF DUAL-CORE NONLINEAR-OPTICAL FIBER

We perform a detailed numerical analysis of soliton-soliton collisions within a standard model of the nonlinear dual-core optical fiber. We demonstrated that, almost in all the cases, the collisions are very st rongly inelastic, typically leading to formation of a breather that de monstrates violent internal vibrations. In particular, if both soliton s are asymmetric and from different branches, the asymmetric breather produced by the collision switches between the two cores with the chan ge of the collision velocity. If the colliding solitons are mutually m irror-symmetric, two asymmetric breathers can be produced. In the case when the two colliding asymmetric solitons are from the same branch, a breather is formed again, symmetric if the solitons are identical. I n this case, the breather demonstrates extremely strong internal vibra tions, compressing itself, from time to time, into very narrow pulses. We also study in detail an interplay between noise, which is always p resent in the fiber, and the soliton-soliton collisions. It is demonst rated that the collision always plays a role of a catalyst strongly en hancing deformation of a stable soliton, or destruction of an unstable one, by the noise.