基于二维材料的非线性光开关是调Q光纤激光器的核心器件，二维材料光开关的浓度会直接影响其非线性光学吸收特性，从而改变脉冲的时域特性。因此，针对二维材料浓度对调Q光脉冲的影响进行了研究，并通过实验制作了基于不同浓度Ti: Bi₂Te₃可饱和吸收光开关，分析了Ti: Bi₂Te₃浓度对非线性光学吸收特性的影响，获得了调Q光脉冲的调制深度、脉冲宽度、重复频率和单脉冲能量随不同浓度Bi₂Te₃的变化关系。最终，针对谐振腔参数对Ti:Bi₂Te₃浓度进行优化，在泵浦功率为71 mW时，获得了中心波长为1 560 nm、脉冲宽度为8 μs，重复频率为14.2 kHz、平均输出功率2.15 mW、对应单脉冲能量为151.4 nJ的脉冲输出。

Nonlinear optical switch based on two-dimensional material is the core device of Q-switched fiber laser. The concentration of two-dimensional material optical switch will directly affect its nonlinear optical absorption characteristics, thus change the time-domain characteristics of the pulse. Therefore, the influence of two-dimensional material concentration on Q-switched optical pulse was studied, and a saturable absorption optical switch based on Ti: Bi₂Te₃ with different concentrations was made through experiments. The influence of Ti: Bi₂Te₃ concentration on nonlinear optical absorption characteristics was analyzed, and the relationship among the modulation depth, pulse width, repetition frequency and single pulse energy of Q-switched optical pulse with different concentrations Bi₂Te₃ was obtained. Finally, the Ti:Bi₂Te₃ concentration was optimized for the resonator parameters. When the pump power is 71 mW, the central wavelength is 1 560 nm, the pulse width is 8 μs, the repetition frequency is 14.2 kHz, the average output power is 2.15 mW, and the corresponding single pulse energy is 151.4 nJ.