Mid-infrared continuous wave parametric amplification in tapered   chalcogenide microstructured fibers
  As photon mixing is not inherently limited to any specific spectral region, parametric processes represent a compelling solution for all-optical signal processing in spectral windows not easily accessible by other technologies. Particularly, the continuous-wave pumping scheme is essential for any application requiring modulated signals or precise spectroscopic characterization. Highly nonlinear fibers enabled record performances for wavelength conversion and amplification in the telecommunication band, however no waveguiding platforms have yet solved the trade-off between high-nonlinearity, low propagation losses and dispersion in the mid-infrared. Here, we show mid-infrared continuous-wave parametric amplification in a GeAsSe fiber. Leveraging state-of-the-art fabrication techniques, a novel tapered photonic crystal fiber geometry enabling 4.5 dB signal amplification and 2 dB idler conversion efficiency is experimentally demonstrated using only 125 mW of pump in the 2 micron wavelength range. This result is not only the first ever continuous-wave parametric amplification measured at 2 micron, in any waveguide, but also establishes GeAsSe PCF tapers as the most promising all-fibered, high efficiency continuous-wave parametric converter for advanced applications in the mid-infrared. 
Sida Xing, Davide Grassani, Svyatoslav Kharitonov, Laurent Brilland,   C\'eline Caillaud, Johann Trol\`es and Camille-Sophie...
physics.optics