Numerical simulation of efficient second harmonic generation in high-index-contrast AlGaAs microring waveguide by using the discrete method

We propose a high-index-contrast AlGaAs microring waveguide for efficient second harmonic generation (SHG) under near-infrared pump. The good overlap occurs between the fundamental modes of pump and second harmonic wave owing to the strong field confinement. The phase matching and resonance conditions can be satisfied through choosing appropriate height and width of the waveguide. In order to deal with the depleted-pump situation and pulse-pumped nonlinear progress, we investigate the wavelength conversion progress by employing the discrete numerical method. The dependence of conversion efficiency on coupling coefficient, pump power and pump wavelength under continuous-wave pump are analysed systematically, and the conversion efficiency can be up to 0.45 for large-scale coupling coefficients with alpha(p) = alpha(s) = 40 dB/cm under 30mW pump. In addition, the pulse-pumped SHG progress is also simulated. Such discrete method also has potential in investigating other resonator-enhanced second-order or third-order nonlinear processes.