Antiresonant hollow core fibre with 0.65 dB/km attenuation across the C and L telecommunication bands

We report a hollow core Nested Antiresonant Nodeless Fibre (NANF) with a loss of 0.65dB/km across the full C and L telecommunication bands. The fabricated fibre is 1.23km long, it is effectively single moded over sufficiently long lengths, and is able to transmit data.