Self-induced-transparency in an Erbium-doped Fiber

The self-induced-transparency (SIT) is a phenomenon of a coherent pulse propagating in a resonant medium without loss and distortion when the pulse energy exceeds a critical value. [1] Since the recent development of the erbium-doped fiber amplifiers, it is interesting to consider the SIT in the silica-based erbium-doped fiber (EDF).[2] It is known that there exist nonlinear Schroedinger (NLS) solitons in the fiber due to the combined effect of the Kerr effect and the negative dispersion. Therefore, the coexistence of a SIT soliton and a NLS soliton has been a subject of intense interest. In Ref.[2], it is shown that impractical large dispersion is required for the SIT-NLS soliton to exist in EDF. In this talk, we extend our previous work [3] on the theory of the SIT-NLS soliton without making the slowly varying envelope approximation (SVEA) and show that it is practical for the SIT-NLS soliton to exist in EDF because the effect of the SIT induces large negative dispersion.