Comparative study of the output characteristics of ytterbium-doped double-clad fiber lasers with different pump schemes

The output characteristics of ytterbium-doped double-clad fiber lasers (YDCFLs) with different pump schemes are compared numerically in detail. The results show that the backward pumped YDCFL with pump reflection for double-pass scheme has the highest conversion efficiency, the most suitable for saving pump powers. As a result of the maximum output power per meter occurring in the forward pumped YDCFL with pump reflection, it means that this kind of pump scheme is preferable for saving YDCF lengths. Moreover, the output characteristic of the bi-directional pumped YDCFL is between forward and backward pumped ones.