Analysis of stability in two-mode laser systems

Stability in two-mode laser systems is analyzed by considering both the gain saturation and the absorption saturation. The analysis shows that the two-mode laser systems could exhibit new types of stability other than previously predicted and have at most triple stable steady states. The influences of the saturation coefficients on the stability are studied. The cross saturation of the gain and that of the saturable absorber are found to have an opposite influence on the stability. Analysis also shows that an increasing ratio of the self-saturation coefficient of the saturable absorber to that of the gain favors the new types of stability, including the tristability.