Fig. 1. Transmission paths of light in fiber. (a) Vertical incidence; (b) incidence at a certain angle

Fig. 2. Relationship between incident angle θ and excitation efficiency of vortex light Pl/P

Fig. 3. Diagram of experimental setup

Fig. 4. Light spots obtained by simulation and experiment. (a) First-order simulation; (b) first-order experiment; (c) LP11 mode simulation; (d) LP11 mode experiment

Fig. 5. Polarization distributions and light spot distributions of TM01, TE01, HE21even and LP11 modes. (a1)-(d1) Polarization distributions; (a2)-(d2) light spot distributions without polarization; (a3)-(d3) light spot distributions with 90° polarization; (a4)-(d4) light spot distributions with 135° polarization; (a5)-(d5) light spot distributions with 180° polarization

Fig. 6. Changes of polarization state and phase of light superimposed by HE21even and HE21odd modes. (a) Polarization state change; (b) phase change

Fig. 7. Light intensity before and after λ/4 wave plate. (a) Light intensity distribution before λ/4 wave plate; (b) light intensity before λ/4 wave plate in x direction; (c) light intensity before λ/4 wave plate in y direction; (d) light intensity distribution after λ/4 wave plate; (e) light intensity after λ/4 wave plate in x direction; (f) light intensity after λ/4 wave plate in y direction

Fig. 8. Diffraction results of vortex light through triangular hole. (a) Vortex light spot; (b) triangle diffraction light spot; (c) light spot simulated in Ref. [25]