Propagation of dark solitons in parity-time symmetric waveguides

Abstract

We study the propagation of dark solitons in the Kerr nonlinearity and parity-time (PT)-symmetric waveguides with Gaussian distribution. Fundamental characters of the dark solitons during the transportation are carefully checked in different parameter regions by the split-time-step Crank–Nicolson method. The results show that the dark solitons are bound to the center of the PT-symmetric waveguide when the central refractive index of the PT-symmetric potential is strong, and the dark soliton tends to deflect toward the gain region due to the gain/loss effect of PT-symmetric waveguide. We also find that when the dark soliton is introduced from the gain region of the PT-symmetric potential, the low-speed dark soliton is reflected by the gain region, and the high-speed dark soliton is bound to the center of the PT-symmetric potential in the corresponding parameter interval.