Hollow-core optical fiber transmits visible light

Current fibers transmit light through silica cores, which have limited room for loss improvement. Another option is the hollow-core fiber (HCF), which theoretically allows for faster speeds due to the ability of light to travel faster through air than through silica. Still, scientists struggled to. Optical fibres form the backbone of the Internet, carrying light signals across the globe. 14 decibels per kilometre even in the best fibres. [pdf]