Spectral attenuation limits of silica hollow core negative curvature fiber

In this paper we discuss the limits of attenuation of silica hollow core negative curvature fibers in the wavelength range from 800 nm up to 4.5 µm. Both numerical and experimental results are presented and show good agreement. A minimum attenuation of 24.4 dB/km was measured at around 2400 nm wavelength, while 85 dB/km was measured at 4000 nm.