The stability of ultrashort pulse output in self mode-locked lasers

In order to discuss the influence of the nonlinear gain saturation on the ultrashort pulses generated from self mode-locked lasers,the differential equations describing the output of this kind of lasers were analyzed by means of Liapunov linear stability theory.It was found that two stationary self mode-locked states appear simultaneously in the laser when the gain saturation energy is lower than a critical value.Only the state with lower energy is stable.With the gain saturation energy increasing,the energy of the stable stationary state increase and its pulse width is shortened,and it should be the working state of the self mode-locked lasers.