The fundamental limits to the attenuation of hollow-core photonic crystal fibres

We propose that the transmission of hollow-core photonic crystal fibres is ultimately limited by scattering from roughness due to frozen-in surface capillary waves. This is confirmed by measurements of the surface roughness in a HC-PCF, the angular distribution of the power scattered out of the core, and the wavelength dependence of the minimum loss of fibres drawn to different scales.