Nontopological Raman-Kerr self-induced transparency solitons in photonic crystal fibers

Using analytical and numerical methods we demonstrate that the pulse propagation equations accounting for the quantum description of the Raman transition and for the optical Kerr nonlinearity have a multiparameter family of nontopological solitary wave solutions. We study properties of these solitons and report the transition from stable to unstable regimes of propagation. We also discuss the feasibility of observation of these structures in gas filled hollow-core photonic crystal fibers.