Fig. 2
From: Hollow-core conjoined-tube negative-curvature fibre with ultralow loss
Bending loss of the CTF. Measured and simulated bending loss spectra for a the bending radius R = 10 cm; b R = 7 cm and c R = 5 cm. Inset: Photo images of the fibre under test with the loop numbers of 200, 270 and 390, respectively
