Bending losses in GeO2 hollow waveguide for CO2 laser delivery

Hollow core waveguides are becoming a potential delivery system of high power CO2 laser for applications in medical and material processing procedures. GeO2 as a kind of cladding material of hollow waveguide with low loss at the wavelength of CO2 laser, has been studied recently. As we know, loss in hollow waveguide increases because of bending, twisting and other reasons. In this paper, bending losses in hollow core GeO2 waveguide were measured by bending the waveguide for known radius of curvature, the bending plane was parallel or perpendicular to the polarization of CO2 laser beam. We also compared our results with those of GeO2-based hollow waveguide.