Demonstration of waveguide regime for chalcogenide hollow-core optical fiber with negative curvature of core boundary from mid- to far-infrared

A new, technologically simple structure of hollow-core optical fiber is proposed, which cladding is formed by eight contiguous capillaries, the surface of the hollow core having a negative curvature. This fiber design provides good light localization: the ratio of radiation intensities at the core center and at the surface of the capillary amounts to eight orders of magnitude. We have previously demonstrated that the optical loss in such a fiber can be incomparably lower than in the material from which it is made.