Graduate School in Nonlinear Science

Sponsored by the Danish Research Academy

MIDIT                               OFD                           CATS
Modelling, Nonlinear Dynamics       Optics and Fluid Dynamics     Chaos and Turbulence Studies
and Irreversible Thermodynamics     Risø National Laboratory      Niels Bohr Institute and 
Technical University of Denmark     Building 128                  Department of Chemistry
Building 321                        P.O. Box 49                   University of Copenhagen 
DK-2800 Lyngby                      DK-4000 Roskilde              DK-2100 Copenhagen Ø
Denmark                             Denmark                       Denmark


by J. G. Caputo
Laboratoire de Physique Mathematique
Universite Montpellier II

MIDIT-seminar 430

Thursday November 26, 1998, 13.00 h
at MIDIT, IMM Building 305, room 027

Abstract: A fiber ring laser generates optical pulses for telecommunications purposes. Two desirable features of the device are a clean self starting to a stable pulse per repetition period and a way to calculate this operating point as a function of the parameters. We show on a model based on a nonlinear Schroedinger equation with saturable gain that both features can be obtained in the solitonic regime with a small amplitude modulation. The operating regime is the fixed point of a map obtained from soliton perturbation theory. We established the validity of this approach by comparison with the full numerical simulations. Finally we discuss possible sources of instability due to resonances in the device.