Nanoimprinting and tapering of chalcogenide photonic crystal fibers for cascaded supercontinuum generation

Improved long-wavelength transmission and supercontinuum (SC) generation is demonstrated by antireflective (AR) nanoimprinting and tapering of chalcogenide photonic crystal fibers (PCFs). Using a SC source input spanning from 1 to 4.2 mu m, the total transmission of a 15 mu m core diameter PCF was improved from similar to 53% to similar to 74% by nanoimprinting of AR structures on both input and output facets of the fiber. Through a combined effect of reduced reflection and redshifdng of the spectrum to 5 mu m, the relative transmission of light >3.5 mu m in the same fiber was increased by 60.2%. Further extension of the spectrum to 8 mu m was achieved using tapered fibers. The spectral broadening dynamics and output power were investigated using different taper parameters and pulse repetition rates. (C) 2019 Optical Society of America