Bistability of the soliton amplitude in a ring resonator with nonlinearly absorbing media

Perturbation theory is used in a study of the dynamics of an optical soliton in a ring resonator with a nonlinearly absorbing cell and external pumping. It is shown that the influence of impurity atoms with a saturable transition may give rise to a hysteretic dependence of the soliton amplitude at the exit from the resonator on the amplitude of a monochromatic pump field.