Parameter modulation in a laser with a saturable absorber

A numerical investigation of the dynamics of self-contained and nonself-contained lasers with saturable absorbers was made for a CO₂ laser with a CO₂ absorption cell. A detailed study was made of the passive Q-switching regime and of its bifurcation with a change in parameters. Special attention was devoted to analyzing the behavior of the nonself-contained system for external active parameter modulation. The choice of the initial conditions was found to exert a strong influence on the state of the system. The mechanisms of a transition to chaotic lasing regimes were identified, these being associated with period-doubling bifurcations, bifurcations with torus formation and collapse, and the interaction of regular and chaotic attractors.