27 research outputs found
A new criterion for the existence of KdV solitons in ferromagnets
The long-time evolution of the KdV-type solitons propagating in ferromagnetic
materials is considered trough a multi-time formalism, it is governed by all
equations of the KdV Hierarchy. The scaling coefficients of the higher order
time variables are explicitly computed in terms of the physical parameters,
showing that the KdV asymptotic is valid only when the angle between the
propagation direction and the external magnetic field is large enough. The
one-soliton solution of the KdV hierarchy is written down in terms of the
physical parameters. A maximum value of the soliton parameter is determined,
above which the perturbative approach is not valid. Below this value, the KdV
soliton conserves its properties during an infinite propagation time
Building patterns by traveling vortices and dipoles in periodic dissipative media
We analyze pattern-formation scenarios in the two-dimensional (2D) complex
Ginzburg-Landau (CGL) equation with the cubic-quintic (CQ) nonlinearity and a
cellular potential. The equation models laser cavities with built-in gratings,
which are used to stabilize 2D patterns. The pattern-building process is
initiated by kicking a localized compound mode, in the form of a dipole,
quadrupole, or vortex which is composed of four local peaks. The hopping motion
of the kicked mode through the cellular structure leads to the generation of
various extended patterns pinned by the structure. In the ring-shaped system,
the persisting freely moving dipole hits the stationary pattern from the
opposite side, giving rise to several dynamical regimes, with the pinned
multi-soliton chain playing the role of the Newton's cradle (NC)
Stability calculations for the ytterbium-doped fiber laser passively mode-locked through nonlinear polarization rotation
We investigate theoretically a fiber laser passively mode-locked with
nonlinear polarization rotation. A unidirectional ring cavity is considered
with a polarizer placed between two sets of a halfwave plate and a quarterwave
plate. A master equation is derived and the stability of the continuous and
mode-locked solutions is studied. In particular, the effect of the orientation
of the four phase plates and of the polarizer on the mode-locking regime is
investigated
Photonic radio frequency down-converter based on parallel electro-absorption modulators in Ku/Ku band for space applications
International audienceIn this paper, we present a new photonic RF frequency down-convertor based on parallel electro-absorption modulators, and fiber Bragg grating filters, with reduced output spurious: only the converted IF signal and first three LO harmonics are present in the output spectrum. We give device performance in terms of conversion gain, noise factor, RF/IF and LO/IF isolations, carrier to third order intermodulation ratio (C/I3) and spectral purity. We also proof that it can work properly in the entire Ku band without a significant variation of performance
Conception de filtres à pertes : comparaison de différentes topologies réalisables en technologie planaire
National audienc
Design of a compact hybrid filter using microstrip resonators and surface mounted cavities
International audienc
Le rĂ´le des sciences face aux crises environnementales
National audienc
Influence of stimulated Brillouin scattering on the dynamics of a self-pulsing fiber laser
International audienc