The Self-Induced Transparency in coherent interaction of light and 2-level atomic system is represented by the Maxwell-Bloch equation. This non-linear equation can be solved by the "Inverse Scattering Transformation", in which the input pulse of light is decomposed into two parts-soliton and radiation. In this work, the soliton spectrum for different shapes of input light pulse is analized quantitatively in one dimension.
It is obtained that the fraction of soliton part energy of the total energy is the more independent of pulse shape, the larger the area of the pulse is.
