在掺铒光纤环形腔内插入未抽运掺铒光纤可形成自组织激光腔。在环形腔多模激光器稳态方程中引入饱和吸收体光栅非线性耦合模方程，建立了全光纤自组织激光腔稳态模型，并得到了边模平坦的单纵模解。仿真分析了激光运行过程中输出耦合器位置、输出比例以及抽运功率等参数对饱和吸收体光栅特性的影响。仿真结果表明，在同等抽运参数与输出比例下，输出耦合器前置式结构较后置式结构中的光栅具有更高的纵模边模抑制比；两种结构下纵模边模抑制比均随输出比例增加而增加，并随抽运功率增加而减小。对前置式结构优化的输出耦合比例取值范围在60%~80%之间。对两种结构激光器的稳定性地图测量证实了仿真结果。

It is known that the all-fiber self-organizing laser cavity can be formed through inserting an unpumped erbium-doped fiber into an erbium-doped fiber ring cavity. The steady state model of this self-organizing laser cavity is established through introducing the nonlinear coupling equations of the saturable absorption grating into the standby equations of the multimode ring laser, and the single-longitudinal-mode solution with flat side mode spectrum is obtained. The influences of the position of the output coupler, output ratio and pump power on the characteristics of the saturable absorption grating are numerically analyzed. The numerical results show that the grating in the prepositive output coupler structure has a higher longitudinal-mode side mode suppression ratio (LM-SMSR) than in the postpositive output coupler structure with the same pump level and output ratio; and in both structures, the LM-SMSRs of the gratings increase with the output ratio but decrease with the pump power. The optimal range of the output ratio for the prepositive coupler structure is 60%~80%. The numerical results are confirmed by the measured stability maps of the lasers with both structures.