采用内包层直径为125 μm 的双包层掺镱光纤，搭建了谐振腔结构全光纤激光器系统，获得了1018 nm 的高功率激光输出。通过优化光纤长度和控制抽运源波长，单模激光输出功率为254 W，光光转换效率达到81%，光谱中无自发辐射光和剩余抽运光，信噪比大于35 dB。由于抽运半导体激光器的输出波长随着输出功率变化，光纤激光器的转换效率也将改变，为了提高转换效率，抽运半导体激光器的输出波长需要精确控制；光纤激光器长期稳定性测试结果表明，4 h 连续工作的不稳定度小于0.5%。本光纤激光器系统是同带抽运高功率光纤激光器的理想抽运源。

A high power level ytterbium doped all-fiber laser at 1018 nm is proposed using the resonant cavity with the 125 μm - diameter double cladding fiber. The single mode high output power of 254 W is achieved with the optical-optical conversion efficiency of 81% via optimizing the length of the gain fiber and controlling wavelength of the pumping LD. The amplified spontaneous emission (ASE) is suppressed efficiently and the residual pumped light is dissipated completely, while the signal to noise ratio (SNR, RSN) is more than 35 dB. As the wavelength of the pumping LD changes with the output power, thus affecting the conversion efficiency of the fiber lasers, the wavelength of pumping LD needs to be controlled accurately for obtaining more efficient conversion efficiency. The output power instability is measured in the experiments with the value of less than 0.5% in four hours. The high efficient fiber lasers at 1018 nm with the stable output power can be applied to the tandem pumping high power fiber lasers as the excellent pump source.