Mid-infrared supercontinuum generation in dispersion-engineered highly nonlinear chalcogenide photonic crystal fiber

摘要

An As2Se3-based chalcogenide highly nonlinear photonic crystal fiber (PCF) with concentric rings consisting of air-holes is proposed to achieve extraordinary flat and small chromatic dispersion in mid-infrared region. This is obtained by design and optimization of the PCF cross-sectional structure. The dispersion variation between +/- 5 ps/(nm . km) is obtained over 800 nm bandwidth. Both the effective mode area and nonlinear coefficient of the proposed PCF within the whole wavelength range from 3 mu m to 5 mu m are investigated. Furthermore, the output supercontinuum (SC) optical spectra for different pump wavelengths located at the normal and abnormal dispersion region are investigated, respectively. The results show that the broadest SC with -20 dB spectral width of 1034 nm covering from 3.887 mu m to 4.921 mu m is obtained for the pump wavelength of 4.357 mu m with 100 fs secant hyperbolic pulse of the peak power of 10 kW. Our PCF design offers a low-cost SC source, which can find potential application in mid-infrared photonics.