Reverse Ridge/Slot Chalcogenide Glass Waveguide With Ultrabroadband Flat and Low Dispersion

A reverse ridge/slot hybrid chalcogenide glass (As₂S₃) waveguide with two vertical silicon dioxide slots is proposed in this paper. The fundamental quasi-TE mode of the waveguide shows an ultraflat dispersion with three zero-dispersion wavelengths. Its dispersion is confined between -26 and +27 ps/nm/km over a bandwidth of 1370 nm (from 1770 to 3140 nm). Two slots in the waveguide introduce the dispersion tailoring effect on the quasi-TE mode, which provides more flexibility for designing the waveguide dispersion. The nonlinear coefficient and the phase mismatching of the degenerate fourwave mixing (FWM) process in this waveguide are calculated, showing that it can support broadband FWM processes in nearand middle-infrared regions.