近年来 ,以双包层光纤为基础的包层抽运技术为提高光纤激光器的输出功率提供了有效途径。利用这种技术光纤激光器的转换效率和输出功率可大大提高 ,光束质量可接近衍射极限 ,因而双包层掺镱光纤激光器成为近几年人们研究的热点。最近 ,我们利用内包层尺寸大的双包层光纤 ,获得 In recent years, the double-clad fiber-based cladding pumping technology to improve the output power of fiber lasers provides an effective way. With this technology, the conversion efficiency and output power of fiber laser can be greatly improved, and the beam quality can be close to the diffraction limit. Therefore, double-clad Yb-doped fiber laser has become a hot spot in recent years. Recently, we have used double clad fiber with large inner cladding