Light transmission in negative curvature hollow core fiber in extremely high material loss region

In this paper we demonstrate the light transmission in a spectral range of 2.5 to 7.9 mu m through a silica negative curvature hollow core fiber (NCHCF) with a cladding consisting of eight capillaries. A separation between the cladding capillaries was introduced to remove the additional resonances in the transmission bands. The measured optical loss at 3.39 mu m was about 50 dB/km under a few modes waveguide regime. (C) 2013 Optical Society of America