Infrared to Terahertz Supercontinuum Generation in a Silicon-Based Rib Waveguide

Spectral broadening of light and generating new frequencies are among the most interesting aspects of nonlinear optics. Supercontinuum generation (SCG) is a especial nonlinear process that occurs when pulses with narrow linewidth or continuous-wave (CW) lightwaves experience huge spectral broadening. In this paper, for the first time, SCG in the terahertz (THz) and Infrared (IR) ranges in a designed silicon-based rib waveguide is simulated by solving the generalized nonlinear Schrödinger equation (GNLSE). To this end, we first design a silicon waveguide with a zero-dispersion wavelength (ZDW) in the THz region and then determine the linear and nonlinear parameters of the waveguide. Subsequently, IR to THz SCG is simulated by means of the split-step Fourier transform (SSFT), where the influences of different parameters such as input pulse width, pulse power and waveguide length are investigated. By launching a 60-fs, 10-kW hyperbolic secant pulse into a 6-mm waveguide, a 1.3-octave SCG is obtained.