窄线宽、单偏振、准单模光纤激光在非线性频率转换、引力波探测、光束合成等领域有广泛的应用需求。然而,受限于受激布里渊散射效应和模式不稳定等因素,国际上公开报道的窄线宽、单偏振、准单模光纤激光的最高输出功率仍然停留在1 k W左右。最近,国防科学技术大学光电科学与工程学院采用级联相位调制方法抑制受激布里渊散射效应,采用增益光纤盘绕技术抑制模式不稳定,成功研制出1.89 k W窄线宽、 Narrow linewidth, single polarization, quasi-single-mode fiber lasers have a wide range of applications in areas such as nonlinear frequency conversion, gravitational-wave detection, beam synthesis and other fields. However, due to the stimulated Brillouin scattering effect and the instability of the mode, the highest output power of narrow linewidth, single polarization and quasi-single mode fiber laser reported in the world remains about 1 kW. Recently, the cascade phase modulation method was used to suppress the stimulated Brillouin scattering effect in the School of Optoelectronics Science and Engineering, National University of Defense Technology, and the gain mode fiber coiled technique was used to suppress the mode instability. A narrow linewidth of 1.89 kw was successfully developed,