Towards hollow-core optical fibers with lower attenuation than silica fibers

Silica glass optical fibers have revolutionized data transmission, sensing and laser development over the past 50 years. Moreover, dielectric waveguides with a hollow core offer exciting development possibilities beyond traditional technology. Hollow Core Optical Fibers (HCFs) have been fabricated over the past 20 years with various geometries and refinements, yet their attenuation has remained significantly higher than can be routinely achieved in standard silica single mode fibers. Here we present recent developments in Nested Anti-resonant Nodeless Fiber (NANF) design over the last few years and show how this rapidly developing technology has been refined to produce state of the art HCFs at wavelengths between 850 – 1625 nm.