title: Modulational instability and space-time dynamics in nonlinear parabolic-index optical fibers.
abstract: Beam propagation in multimode graded-index parabolic optical fibers in the presence of group-velocity dispersion and Kerr nonlinearity is theoretically investigated. It is shown that a modulational instability arising from the periodic spatial focusing of the beam takes place regardless of the sign of fiber dispersion, leading to a highly nonlinear space-time dynamics and the generation of ultrashort optical pulses.
authors.affiliation: Istituto Nazionale per la Fisica della Materia, Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci, Milan 32 I-20133, Italy. longhi@fisi.polimi.it
authors.forename: Stefano
authors.initials: S
authors.lastname: Longhi