Symmetry breaking breathers and their phase transitions in a coupled optical fiber system

we report novel symmetry breaking breathers of an optical fiber system governed by a set of generalized nonlinear coupled Schrödinger equations. Via introducing Darboux transformation method, the vector breather solutions are constructed for the system. For a small perturbation to the coefficient parameter which represents mixed higher-order dispersion and nonlinearity, symmetry breaking vector breathers can be observed. As the integral parameter is adjusted, these breathers will switch between different phases. Our study reveals theoretically the formation and transition mechanisms of symmetry breaking vector breathers and helps explain the corresponding experimental results.