The fiber mode coupler has become an important choice for the generation of all-fiberultra-short pulsed vortex beams due to its wide working bandwidth and high efficiency mode coupling. In this paper, we first studied the vector mode characteristics of single-mode fiber, few-mode fiber and hollow-core fiber, and designed the single-mode-few-mode fiber (SMF-FMF) mode couplers and single-mode-hollow-core fiber (SMF-HCF) mode coupler for Ytterbium-doped fiber lasers. Then, the numerical simulation software is utilized to study the coupling characteristics of the mode coupler, and analyze the relationship between the core distance and the coupling efficiency. The simulation results show that the SMF-FMF coupler can convert LP01 mode to LP11 or LP21 mode, with a coupling efficiency of over 96%. In addition, the SMF-HCF coupler can convert HE11 into HE21 or HE31 mode with a coupling efficiency of over 82%. The SMF-FMF mode coupler and SMF-HCF mode coupler lay the foundation for obtaining large topologically charged ultra-short pulsed vortex beams based on ytterbium-doped mode-locked fiber lasers.