Deep-ultraviolet to mid-infrared supercontinuum generated in solid-core ZBLAN photonic crystal fibre

Silica-based photonic crystal fibre has proven highly successful for supercontinuum generation, with smooth and flat spectral power densities. However, fused silica glass suffers from strong material absorption in the mid-infrared (>2,500 nm), as well as ultraviolet-related optical damage (solarization), which limits performance and lifetime in the ultraviolet (<380 nm). Supercontinuum generation in silica photonic crystal fibre is therefore only possible between these limits. A number of alternative glasses have been used to extend the mid-infrared performance, including chalcogenides, fluorides and heavy-metal oxides, but none has extended the ultraviolet performance. Here, we describe the successful fabrication (using the stack-and-draw technique) of a ZBLAN photonic crystal fibre with a high air-filling fraction, a small solid core, nanoscale features and near-perfect structure. We also report its use in the generation of ultrabroadband, long-term stable, supercontinua spanning more than three octaves in the spectral range 200-2,500 nm.