为了获得窄线宽、高功率、长波长(相对于1030nm~1080nm)的1120nm光纤激光器，采用普通单模掺镱光纤和一对光纤布喇格光栅构建了该光纤激光器的谐振腔，为保证抽运光的完全吸收和避免非线性效应，对有源光纤的最佳长度进行了理论分析和实验验证。结果表明，激光器的阈值抽运功率为40mW、注入抽运功率为265mW时，激光器输出信号光功率35mW，光光转换效率为13.2%,激光器中心波长为1120.9nm，输出激光的谱线宽度为0.03nm。这种激光器的获得是因为采用了高反射率耦合输出光纤布喇格光栅、短谐振腔结构和低功率运转状态。该激光器可作为种子光注入光纤放大器。

In order to realize 1120nm ytterbium-doped fiber laser with narrow linewidth, high power level, long wavelength (compared with 1030nm~1080nm), the resonator of fiber laser was composed of a normal single-mode Yb-doped fiber and a pair of fiber Bragg gratings (FBG). The theoretical-optimized active fiber length is used to ensure that pump light is entirely absorbed and nonlinear effect is suppressed. After theoretical analysis and experimental verification, the results show that when laser threshold pump power is 40mW and the launched pump power is 265mW, laser output signal power is up to 35mW with optical-to-optical conversion efficiency of 13.2%, central wavelength of 1120.9nm, output light linewidth of 0.03nm. The performances of the laser contribute to high reflectivity output coupler FBG, short cavity and low power operation. The laser can be injected into fiber amplifiers.