Exact field decomposition for TM waves in nonlinear media

Abstract
We show that the electric field components Ex and Ez of a transverse magnetic (TM) wave propagating in a nonlinear medium can be formally decomposed through a conservation law, provided that ∂xx/∂Ez2 = ∂zz/∂Ex2. If this condition is satisfied, then the electromagnetic field distribution can be exactly obtained by quadrature. For the case of a guided nonlinear TM mode, our procedure can be employed to establish the eigenvalue equation directly.