The self-starting dynamics of a model for passively mode-locked lasers with saturable absorber, in which the optical amplifier has a saturable nonlinearity, is examined. The basic assumption is that the laser will operate in the mode-locked regime when the continuous-wave regime becomes unstable. Within the framework of the modulational-instability analysis, a global map for the laser self-starting criteria is constructed. According to this map, the saturable nonlinearity enhances the input-field intensity required for laser self-starting. Analytical expression of the zero modulation-frequency regime of this threshold input field is derived, which turns out to be valid in the normal as well as in the anomalous dispersion regime, where evidence of self-starting is also given.

中文翻译：

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具有可饱和吸收体和可饱和非线性的被动锁模激光器的动力学

研究了具有可饱和吸收体的被动锁模激光器模型的自启动动力学，其中光放大器具有可饱和非线性。基本假设是，当连续波状态变得不稳定时，激光器将在锁模状态下工作。在调制不稳定性分析的框架内，构建了激光自启动标准的全局图。根据该图，可饱和非线性增强了激光自启动所需的输入场强度。推导出该阈值输入场的零调制频率范围的解析表达式，结果证明它在正常和异常色散范围内都是有效的，其中还给出了自启动的证据。