Dynamics of spatial solitons in laser with saturable absorber

The theoretical model of spatial soliton formation in lasers with saturable absorber based on the set of Maxwell-Bloch equations has been developed. The case of fast saturable absorber is considered. An analytical solution in form of one-dimensional laser autosolitons is obtained and the problem of soliton stability in respect with spatially inhomogeneous perturbations is analyzed. It is shown that the solitons in laser with fast saturable absorber are metastable and they decay to homogeneous lasing or non-lasing mode via repulsion of spatial domain walls. The results of numerical calculations of dynamics of the light field in the laser cavity, based on explicit and non-explicit two-layer finite-difference approximation of the laser field equation, illustrate the main features of the process of laser spatial solitons formation and evolution