title: Corrections to coupled mode theory for deep gratings
abstract: We generalize the standard coupled mode equations describing interactions between forward and backward propagating waves in a nonlinear optical Bragg grating. Including the lowest order corrections of the grating depth, we obtain a Hamiltonian system that can be regarded as an extension of the usual coupled mode equations for shallow gratings. The results are consistent with existing results based on a Bloch wave expansion. We also obtain exact traveling solitary wave solutions, that can be regarded as a generalized gap soliton, modified by the grating's depth.
authors.affiliation: Optical Sciences Centre, Research School of Physical Sciences and Engineering, The Australian National University, Canberra ACT 0200, Australia and Department of Physics, Faculty of Science, Ehime University, Ehime 790-8577, Japan*.
authors.initials: T
authors.lastname: Iizuka
authors.lastname: de Sterke CM