Hollow-core fibers with reduced surface roughness and ultralow loss in the short-wavelength range

In all fiber optics, loss in the visible and UV is restricted by scattering. By improving the core roughness of hollow-core fibers, record attenuation values at short-wavelengths were achieved, opening exciting prospects in visible and UV-photonics. While optical fibers display excellent performances in the infrared, visible and ultraviolet ranges remain poorly addressed by them. Obtaining better fibers for the short-wavelength range has been restricted, in all fiber optics, by scattering processes. In hollow-core fibers, the scattering loss arises from the core roughness and represents the limiting factor for loss reduction regardless of the cladding confinement power. Here, we report on the reduction of the core surface roughness of hollow-core fibers by modifying their fabrication technique. The effect of the modified process has been quantified and the results showed a root-mean-square surface roughness reduction from 0.40 to 0.15 nm. The improvement in the core surface entailed fibers with ultralow loss at short wavelengths. The results reveal this approach as a promising path for the development of hollow-core fibers with loss that can potentially be orders of magnitude lower than the ones achievable with silica-core counterparts.

Automated summary

Improving the core roughness of hollow-core fibers leads to record low attenuation values at short-wavelengths, opening up exciting prospects in visible and UV-photonics.