Design and modeling of the nonlinear properties of octagonal lattice Ge20Sb5Se75 photonic crystal fibers

Abstract

Most silica photonic crystal fibers have limited spectral broadening in the infrared region, making them less than ideal in terms of technological applications. In this work, we propose a new Ge20Sb5Se75 chalcogenide octagonal photonic crystal fiber that provides diverse dispersions with all-normal and anomalous regimes and multiple zero-dispersion wavelengths. The nonlinear properties are investigated over a wide wavelength range up to 14 µm by numerically solving Maxwell's wave equations using Lumerical Mode Solutions software. The full-vector finite-difference eigenmode method minimizes the losses so that low confinement losses in the short-wavelength region of 1 − 6 µm are found and nonlinear coefficients as high as thousands of W−1.km−1 are achieved. Three fibers with an all-normal dispersion profile and anomalous dispersion with one or three zero dispersion wavelengths are proposed for supercontinuum generation. The fibers provide small dispersion values of −0.88, 0.08, and 1.646 ps/(nm.km) at suitable pump wavelengths. Furthermore, the very small confinement loss of approximately 10−5 to 10−11 dB/m is the outstanding advantage of these optical fibers. A broadband spectrum with low input power is expected as a result of the proposed fiber-based supercontinuum generation.