Polarization-insensitive reverse-ridge AlGaAs waveguide for the mid-infrared supercontinuum generation

In this paper, a polarization-insensitive reverse-ridge AlGaAs waveguide is designed for the supercontinuum generation. In the considered wavelength range from 3.4 to 8 mu m, the dispersion profiles, nonlinear coefficients, and effective mode field areas for the quasi-TE and quasi-TM modes coincide well. The simulation results show that when pump pulse with wavelength of 4.2 mu m, peak power of 4.8 kW, and width of 90 fs is launched into the anomalous dispersion region of the quasi-TE and quasi-TM modes of the 3.4-mm-long waveguide, the two generated SCs overlap well. For the quasi-TE and quasi-TM modes, the SCs generated extend from 2.17 to 8.53 mu m and 2.23 to 8.61 mu m, respectively, spanning more than 1.95 octaves. The proposed reverse-ridge AlGaAs waveguide structure is expected to provide a possible solution for alleviating the undesired polarization effect related to the nonlinear dynamics.