Highly nonlinear spiral shaped photonic crystal fiber in a Ga-Sb-S chalcogenide glass for nonlinear applications

摘要

We numerically report a design of a highly nonlinear spiral-shaped photonic crystal fiber (PCF) in Ga_8Sb_(32)S_6o chalcogenide glass for nonlinear applications in mid-infrared region. We have tailored the structural parameters to obtain all-normal and nearly zero flat-top dispersion profile. A flat-top dispersion curve is obtained with a negative dispersion value of -98.63 ps.nm~(-1) km~(-1). This structure possesses a very high nonlinear coefficient of 49190 W~(-1)km~(-1) with effective mode area of the propagating fundamental mode as 0.833 μm~2 at a pump wavelength of 1.9 μm. This highly nonlinear spiral-shaped PCF is suitable for the generation of an ultra-broadband supercontinuum spectrum in mid-IR domain. Various nonlinear applications of supercontinuum generation are pump-probe spectroscopy, nonlinear microscopy, metrology, frequency combs generation and optical coherence tomography.