Darboux transformation and dark soliton solution for the defocusing Sasa–Satsuma equation.

In this Letter, the Darboux transformation is first applied to the defocusing Sasa–Satsuma equation which describes the propagation dynamics of ultrashort light pulses in the normal dispersion regime of optical fibers. The N -fold iterative transformation is expressed in terms of the determinants. This transformation enables us to construct explicit analytical dark soliton solutions from non-vanishing background. In illustration, the single-dark soliton solution is presented from the once-iterated formula. [ABSTRACT FROM AUTHOR]