Broadband Guidance in a Hollow-Core Photonic Crystal Fiber With Polymer-Filled Cladding

In this letter, we report for the first time (to the best of our knowledge) the ability of a conventional hollow-core photonic crystal fiber (HC-PCF) to guide light over a wide bandwidth by selectively filling the cladding of the fiber with polymeric material. The transmission spectrum of the new fiber was recorded using a supercontinuum source while the measured near-field profile, combined with the numerical analysis, verified the existence of a single white fundamental guided mode in the air-core. The main advantage of the proposed method is that broadband guidance in air can be easily achieved, avoiding complex and sophisticated designs as well as fabrication of the fiber cladding structure, thus opening new prospects for the HC-PCF.