In this paper, we theoretically demonstrate enhanced supercontinuum generation in a trench-assisted silicon–germanium (Si–Ge) rib waveguide on a sapphire substrate. The computational analysis of the proposed design is done by solving the nonlinear Schrödinger equation using the Split-Step Fourier Method (SSFM) in MATLAB and finite element method (FEM) simulations. By incorporating sidewall trenches, the waveguide exhibits a 30.07% reduction in the effective mode area of the fundamental mode at a pump wavelength of 3.5Formula: see textFormula: see textm, leading to a 42.98% increase in the nonlinear coefficient. These enhancements intensify nonlinear interactions such as self-phase modulation and soliton dynamics, resulting in a broader and more intense supercontinuum spectrum. Using the SSFM with secant hyperbolic pump pulses centered at 3.5Formula: see textFormula: see textm having a pulse width of 45Formula: see textfs and a peak power of 5Formula: see textkW, we simulate supercontinuum generation and compare the results with those of a conventional rib waveguide. While the standard design yields a coherent spectrum spanning 1.7–6.2Formula: see textFormula: see textm, the trench-assisted configuration extends the bandwidth to 1.6–7.4Formula: see textFormula: see textm. The suggested waveguide design can serve as a potential candidate for mid-infrared supercontinuum sources, with strong potential for applications in spectroscopy, environmental sensing, biomedical diagnostics, and free-space optical communication.
Garg et al. (Wed,) studied this question.