Fig. 1. Designed Nested HC-ARF model. (a) Structural diagram; (b) simulated loss spectrum

Fig. 2. SEM images of fabricated Nested HC-ARF

Fig. 3. Transmission and loss properties for fabricated Nested HC-ARF. (a) Transmission spectra of 640 m and 10 m long fibers under same coupling condition; (b) fiber-loss spectrum measured by cut-back method

Fig. 4. Model features for fabricated Nested HC-ARF. (a) Group delay plot of 8 m long fiber by S² imaging technique with reconstructed mode profiles in insets; (b) MCR for different fiber lengths and LP₁₁ mode loss