Generalized Theory of One-Dimensional Steady-State Optical Spatial Solitons

We present a generalized soliton theory based on the one-dimensional generalized nonlinear Schrödinger equation, from which one can easily obtain the bright, dark, and grey soliton waveforms, and their existence curves. We show that the forming conditions of spatial solitons are directly dependent on the relationship between the index perturbation and the intensity, no matter whether the index perturbation is positive or negative. Some relevant examples are presented when the solitons are supported by the photoisomerization nonlinearity.