Optical properties of a Si3N4 nanowaveguide and its broadband infrared spectra

By calculating the optical parameters of a silicon nitride nanowaveguide, the supercontinuum spectra generated through the desired waveguide is simulated making use of the generalized nonlinear Schrödinger equation which governs the supercontinuum generation process. The dispersion coefficients for three different values of a structural parameter of the waveguide have been calculated from the reported dispersion profiles of the nanowaveguide. The pulse propagation of a sech-shaped pulse (1 kW, 30 fs) through the waveguide is simulated making use of the fourth-order Runge–Kutta method. Here, the simulated supercontinuum spectra are compared for different values of the chosen geometric parameter. At a specific geometry of the silicon nitride waveguide, an extreme spectral broadening is generated, especially in the infrared region. It can be observed that the generated supercontinuum spectra from the structure with the structural parameter \({ H_2}\) equals to 50 nm is broader than the others, which is due to the presence of multiple zero-dispersion wavelengths in its dispersion profile. The generated supercontinuum spectra cover a wavelength range of 1260–5200 nm with a flatness of 30 dB. Furthermore, the soliton dynamics through this supercontinuum process have been discussed.