Butterfly-shaped pulse in optical fibers with variable group-velocity dispersion

Butterfly-shaped pulse in optical fibers with variable group-velocity dispersion is reported for the first time. The nonlinear Schrödinger equation, which describes the pulse propagation in optical fibers with variable group-velocity dispersion, is investigated, and the analytic solution for this equation is derived. The cosine dispersion profile of optical fibers is suggested to obtain the butterfly-shaped pulse. The physical effects affecting the butterfly-shaped pulse properties is discussed