| Sign-alternated-dispersion SiN waveguides for super continuum generation. a) An illustration of integrated waveguide structure 1 and structure 2. The darker region indicates the silicon nitride core, while the lighter region corresponds to the silicon oxide cladding. The overall lengths of both structures are indicated, and the amounts of ND and AD segments are also shown. Nonlinear pulse propagation is shown through the qualitative dynamics of the illustrated electric field profiles. The length and width of the segments are not shown to scale. For the exact geometrical dimensions of the waveguides, refer to Supporting Information I. b) Calculated dispersion profiles of the s-polarized mode versus wavelength for the AD segment of 1350 nm width (shown in red) and the ND segment of 650 nm width (shown in blue). The associated nonlinear coefficients of the waveguides are indicated as well. The shaded region is the wavelength range where the sign of dispersion is inverted. c) Dispersion profiles for p-polarizations, analogous to panel (b). d) Illustration of the experimental setup. A fiber laser delivering ultrashort pulses was used as the source. PBS refers to polarization beam splitter, DM refers to dielectric mirror (1550 nm), SM to broadband silver mirror, and MM refers to multi-mode fiber. Optical spectrum analyzer (OSA) refers to near-infrared or visible range optical spectrum analyzers (Ocean View NirQuest256 and Ando AQ6315A spectrum analyzer). |
