137967.fig.0012a
(a)
137967.fig.0012b
(b)
Figure 12: Power curves as a function of the propagation constant , obtained from (22) with . (a) Regime 1 with and and (b) regime 2 with and . The + and − signs in the legends refer to the choice of solution in (20a) and (20b). Lower (upper) solution branches appear as red (blue) lines, and each branch generally satisfies the VK stability criterion [61].