  The excitation of soliton states in optical layers exhibiting Kerr
nonlinearities is theoretically investigated. The optical transmission
coefficient is obtained as a function of the nonlinearity power of an incident
monochromatic electromagnetic wave polarized in the transverse electric
configuration. In materials exhibiting a defocusing nonlinearity, soliton
excitations are not observed if the nonlinearity power associated with the
incident electromagnetic wave is below a well-defined value. At such a limiting
value of the nonlinearity power, a soliton excitation with an electric-field
amplitude independent of the position is found within the nonlinear layer,
regardless of the incident-wave frequency value.
