Fig. 1. Structure of 19 cell HC-PBGF. (a) Partial diagram of designed structure; (b) SEM image of cross section of prepared fiber

Fig. 2. Structure of single ring 6-tube HC-ARF. (a) Partial diagram of designed structure; (b) SEM image of cross section of prepared fiber

Fig. 3. Transmission spectra and loss spectra of 5 m long fiber in flat state. (a) HC-PBGF; (b) HC-ARF

Fig. 4. Bending losses and mode field distributions of fundamental modes of HC-PBGF and HC-ARF fiber under different bending radii at wavelength of 1550 nm with bending direction of fiber shown by black arrow. (a) Bending losses; (b) mode field distributions of fundamental modes

Fig. 5. Diagram of bending loss test device

Fig. 6. Bending loss spectra of HC-PBGF measured at different bending radii with optical fiber wrapped around quartz rod with diameter of 0.5 cm shown in inset

Fig. 7. Bending loss spectra of HC-ARF