Fabrication and Characterization of Tapered Single-Ring Hollow-Core Photonic Crystal Fibre

Thermal tapering of step-index and photonic crystal fibres (PCF) has recently emerged as an effective tool for controlling nonlinear optical effects through offering axially varying dispersion and high effective nonlinearity [1,2]. At the same time, rapid developments in hollow-core PCF have opened up new possibilities for gas-based nonlinear optics. In particular, single-ring PCF (SR-PCF), consisting of a circular ring of thin-walled capillaries surrounding a central hollow core, can offer low-loss, easily predictable windows of transparency, effectively single-mode guidance and is relatively simple to fabricate [3]. Here we show, for the first time to our knowledge, the fabrication and non-invasive characterization of tapered SR-PCF.