These analytical estimates are shown with the dashed lines in Figure 11.6.
It is interesting to compare these results with those obtained in the framework of
the coupled-mode theory (see Section 11.2.3), valid for a narrow bandgap (i.e., for
small a and small I0). Although the nonlinear coupling coefficient in Eq. (11.2.20)
is different than that of the coupled-mode theory for shallow gratings [66], the key
stability result remains the same--the oscillatory instability appears above a certain
critical intensity proportional to the bandgap width. In our case, the bandgap width ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month, and much more.