Reversed Self-steepening in Si₃N₄-organic Hybrid Slot Waveguides with Engineered Nonlinearity

Dispersion of nonlinearity greatly influences both temporal and spectral evolutions for ultrashort pulses, although difficult to be tailored in a wide spectral range. Here, we show the hardly observable reversed self-steepening in an on-chip Si 3 N 4 -organic hybrid slot waveguide with sophisticated dispersion and an increased nonlinear coefficient with wavelength. An octave-spanning supercontinuum with significant red-shift spectral broadening and a rectangle-shaped pulse waveform with a sharp rising edge of 13 fs can be generated. We study the robustness of reversed self-steepening under different operating conditions and reveal its nonlinear dynamics. This deepens the understanding on the dispersion of nonlinearity and helps develop novel nonlinearity-engineered devices for on-chip optical shock formation, pulse shaping, and signal processing in the future.