In recent years, more efforts have been devoted to the research of ultrashort pulses with high average power for various applications such as pumping of optical parametric oscillators, material micromachining, multi-photon imaging, and terahertz applications[1–3]. At present, the Ti:sapphire laser is limited to output power below 4 W due to the lower pump power and the quantum efficiency of the crystal. In addition, its pump source is quite expensive. In contrast, the -doped femtosecond laser has more great potential because it can be pumped by tens or even hundreds of watts laser diodes (LDs), and the center wavelength ranges from 0.9 µm to 1.1 µm. Despite there being many reports on Yb-doped lasers, the trade-off between the average power and pulse duration was still a challenging topic. Therefore, it is very crucial to choose a novel gain medium to meet a wide spectrum supporting the generation of shorter pulses and good thermo-mechanical properties allowing for high-power laser pumping.