Fig. 1. Schematic of cross-sectional structure of air-core anti-resonant fiber. (a) Single-core structure; (b) three-core structure

Fig. 2. Mode field distribution of air-core anti-resonant fiber

Fig. 3. Mode field distribution for three-core configuration with D₁=4.8 mm. (a) Even-mode; (b) odd-mode

Fig. 4. Relationship between D₁ and coupling length

Fig. 5. Relationship between D₁ and loss. (a) Confinement loss; (b) absorption loss; (c) total loss

Fig. 6. Relationship between d_r and coupling length

Fig. 7. Relationship between d_r and loss. (a) Confinement loss; (b) absorption loss; (c) total loss

Fig. 8. Transmission curves at the side core of three-core configuration

Fig. 9. Insertion losses as functions of frequency

Fig. 10. Transmission loss of the even and odd modes in three-core structure

Fig. 11. Diagram of two-core structure

Fig. 12. Insertion losses as functions of frequency for two-core structure