Fig. 1. Fiber structure. (a) Schematic diagram of twisted fiber; (b) cross-section view of fiber simulation

Fig. 2. Variation of confinement loss with wavelength for different modes when outermost two layers of air holes are not present

Fig. 3. Phase diagram of twisted fiber partial mode. (a) HE_7,1 mode; (b) HE_9,1 mode

Fig. 4. Electric field intensity distribution diagram of twisted fiber partial mode. (a) HE_7,1 mode; (b) HE_9,1 mode

Fig. 5. Situation where effective refractive index difference between adjacent modes varies with wavelength

Fig. 6. Variation of purity corresponding to each topological charge with wavelength

Fig. 7. Situation where mode field areas of different modes change with wavelength

Fig. 8. Relationship between nonlinear coefficients of different modes and wavelength

Fig. 9. Variation of dispersion with wavelength for different modes

Fig. 10. Variation of confinement loss with wavelength for different modes