Figure 5.

Simulated stability chart for different additional frequency shift values. (a)–(c) The blue region represents the existence range of dark soliton states in the presence of the Raman interaction ($f_{\mathrm{R}}=0$.18) for various additional frequency shift values of (a) $a=1$, (b) $a=2$, (c) $a=4$. The red region where dark soliton states exist in the absence of the Raman interaction ($f_{\mathrm{R}}=0$) and the green region where SRS is excited in the absence of the additional frequency shift are shown for comparison. The existence range for dark soliton states with the Raman interaction (blue) is narrower than the one without the Raman interaction (red). The blue region increases along with the additional frequency shift, but decrease after its maximum value (not shown here).