Mid-infrared nonlinear silicon hybrid waveguide with high figure of merit

Mid-infrared (MIR) integrated waveguides with strong local field enhancement and relatively low loss have shown their potential in nonlinear optical applications. We present a novel highly nonlinear silicon hybrid waveguide by setting an insulator-metal-insulator structure with [2-[4-(dimethylamino)phenyl]-3-([4-(dimethylamino)phenyl]ethynyl)buta-1,3-diene-1,1,4,4-tetracarbonitrile] (DDMEBT) and silver materials into the silicon slot. The mode field is strongly confined in the DDMEBT layers via the surface plasmon polariton effect. Two rectangular silicon nanobridges are used to further confine the optical field and reduce the loss simultaneously. The waveguide dimensions are optimized to obtain a figure of merit as high as 0.55 at 2.1 mu m and a zero-dispersion wavelength of 2.06 mu m. In a 6.6-mm-long waveguide, a maximum four-wave mixing efficiency of -6.65 dB and a bandwidth of 512 nm (1.894-2.406 mu m) can be simultaneously obtained, pumped by a 2.104-mu m source with a power of only 500 mW. Our designed waveguide exhibits excellent overall performance for nonlinear optical applications such as all-optical signal processing in the MIR band. (C) 2018 Optical Society of America