Design of all-normal dispersion based on multi-material photonic crystal fiber in IR region for broadband supercontinuum generation

In this paper, we proposed a design of highly nonlinear all-normal dispersion photonic crystal fiber (PCF) based on highly nonlinear chalcogenide material of As2S3 with the first air-hole ring replaced with borosilicate glasses. The innovative design has a unique effective-index profile that can offer not only near-zero dispersion at the pumping wavelength but also zero dispersion slope for a wide wavelength range along with low leakage loss. Our numerical analysis establishes that the optimized design offers a high nonlinear coefficient as large as 1642  W−1  km−1 with a very small all-normal dispersion of −0.086  ps/nm/km around the wavelength of 2.80 μm designed by replacing the inner air-hole ring with borosilicate glasses in a PCF with As2S3 background. The optimized fiber demonstrates wideband supercontinuum generation in the infrared region with 20 dB bandwidth of 740 nm with an erbium (Er3+)-doped ZBLAN fiber laser emitting at 2.8 μm as the pump source with a peak power of 350 W with only a few centimeters of the optimized fiber and thereby reducing the propagation loss drastically.