Saturation and absorption effects on the transmission properties of Kerr-type nonlinear layers

The effects of absorption and saturation on soliton states in Kerr-type nonlinear layers are
theoretically investigated. In addition to the usual gray and bright soliton structures observed in nonlinear
slabs, a flat soliton, i.e., a particular soliton excitation with electric field amplitude independent of the
position within the layer, is researched in cases of self-defocusing and self-focusing nonlinearities. Effects
caused by the combination of absorption and saturation, such as the shift and extinction of the flat soliton
peak, the decrease in the amplitude of the electric field within the nonlinear layer, and the suppression of
the multistable behavior of the transmission coefficient in the vicinity of the soliton peaks, are discussed.
The present theoretical results are compared and found in good quantitative agreement with previous
experimental measurements.