Self-Formation of Temporal Dark Solitons in a Single-Mode Optical Fiber

The process of dark pulse formation in a dispersion delay line using amplitude-phase filtering and, subsequently, self-formation of a dark soliton from it in a single-mode optical fiber has been investigated. A dispersive delay line is a system widely used in ultrashort pulse generation applications, consisting of a pair of diffraction gratings or prisms and a beam-returning mirror, in which the laser pulse is stretched and given a negative chirp. The magnitude of the error in fulfilling the conditions necessary for the self-formation of dark solitons has been estimated. A detailed study of the features of the radiation spectrum containing a dark soliton was carried out. The stability of the region corresponding to the dark soliton in the spectrum and its two-peak nature, which is of interest for ultrafast spectroscopy, were revealed.