The evolution feature of chirp-dark soliton in single-mode fiber

The evolution feature of the injected initial-chirp tanh-dark soliton in single-mode fiber is studied in this paper. We analyze the evolution of amplitude, pulse width, frequency chirp and center position shift of dark soliton along with the variation of propagation distance, primarily using Lagrange-Euler's formula and taking the high-order dispersion as perturbation. The results show that the amplitude and pulse width of chirp-dark soliton are all oscillating around a certain critical distance in ideal fiber (beta=0), and the high-order dispersion conduces to generate the asymptotic dark soliton.