与光纤放大器相比，光纤激光振荡器具有结构紧凑、稳定性好、模式不稳定性阈值高、光束质量优良等优点。对单端抽运的1 kW级全光纤激光振荡器进行了详细的理论和实验研究。建立了考虑光纤弯曲、模式耦合、抽运波长变化、包层光滤除的速率方程模型；利用国产合束器，搭建了单端抽运全光纤振荡器，在抽运功率为1.5 kW时，获得1.04 kW功率输出，光光效率为69%。对不同输出功率的光束质量进行测量，光束质量M2均小于1.25。激光器稳定工作1 h，功率起伏小于1%。

Compared with fiber amplifier, fiber laser oscillator has the advantages of compact structure, good stability, high threshold of mode instability and good beam quality. Single-end pumped 1 kW all fiber laser oscillator is studied in detail theoretically and experimentally. Rate equation model which considers the fiber bending loss, mode coupling, changing pumping wave and cladding lights stripping is presented. Using a China made combiner, a single-end pumped all fiber laser oscillator is built. Laser power of 1.04 kW and optical to optical efficiency of 69% are obtained when the pump power reaches to 1.5 kW. The beam quality is measured and the results show that the M2 factors are all less than 1.25 in different powers. With one hour steady laser operation, the power fluctuation is less then 1%.