Development of low loss, wide bandwidth hollow core photonic bandgap fibres for telecom applications

Abstract

Hollow core Photonic Bandgap Fibres (PBGFs) with a 19-cell core geometry and displaying ultralow loss over record 3 dB transmission bandwidths have been developed. In particular, we demonstrate PBGFs with as low as 4.5 dB/km loss at 2 μm and over >;150 nm wide sub-10 dB/km transmission. Absorbing gas species present in our fibres were identified and their loss contribution quantified. An initial explanation on the origin of CO2 absorption around 2 μm is formulated along with possible means for its removal.