DOYA , Valérie

The purpose of this article is to analyze the impact of an index segmentation on the ray dispersion in the geometrical approach. The presented study re- veals that a periodic index segmentation of the waveguide along with a trans- verse gaussian index variation exhibits complex ray dynamics that strongly modify ray dispersion properties.

In this article it is shown that for specific initial conditions an input beam injected in a Multimode Periodic Segmented Waveguides (MPSW) does not di ract and remains collimated all along the waveguide whereas a speckle like pattern is expected at the output of a multimode structure. This nonintuitive behavior can be explained with the help...

In this article it is shown that for specific initial conditions an input beam injected in a Multimode Periodic Segmented Waveguides (MPSW) does not di ract and remains collimated all along the waveguide whereas a speckle like pattern is expected at the output of a multimode structure. This nonintuitive behavior can be explained with the help...

n this article, it is shown that multimode periodic segmented waveguides (PSW) are versatile optical systems in which properties of wave chaos can be highlighted. Numerical wave analysis reveals that structures of quantum phase space of PSW are similar to Poincare sections which ́ display a mixed phase space where stability islands are...

In this article, we present a numerical analysis concerning ray propagation in a multimode periodic segmented waveguide with a gaussian index segment profile. We show that this simple waveguide configuration exhibits a complex ray dynamics that can be regular or chaotic depending on the initial conditions.

We report the analysis of multimode pump absorption in double-clad rare-earth-doped fibers under realistic bending conditions. The finite-element beam-propagation method is used for the analysis. The fiber bending is approximated by the transformation of the refractive index profile of the fiber. Double-clad fibers of hexagonal, circular and...

A multimode optical fiber with a truncated transverse cross section acts as a powerful versatile support to investigate the wave features of complex ray dynamics. In this paper, we concentrate on the case of a geometry inducing mixed dynamics. We highlight that regular modes associated to stable periodic orbits present an enhanced spatial...

In this letter we propose an original mechanism to select scar modes through coherent gain amplification in a multimode D-shaped fiber. More precisely, we numerically demonstrate how scar modes can be amplified by positioning a gain region in the vicinity of specific points of a short periodic orbit known to give rise to scar modes.

The modes properties of highly multimode optical fibre are governed by the rays' dynamics in the geometrical limit. Different regimes of dynamics are encountered by modifying the geometry of the transverse cross section of the fibers. We show that the selection of modes in a highly multimode fiber can be simplied thanks to the signature of the...

We propose to use a multimode optical fiber with a D-shaped cross section as a privileged system to image wavefunctions of a chaotic system. Scar modes are in particular the sub ject of our investigations. We study their imprints on the statistics of intensity and we show how the introduction of a localized gain region in the fiber is used to...

International audience

Ever extending applications of fiber lasers require energy efficient, high-power, small footprint and reliable fiber lasers and laser wavelength versatility. To meet these demands, next generation of active fibers for high-power fiber lasers is coming out that will eventually offer tailored spectroscopic properties, high robustness and reduced...

In this paper, we present a non-standard fibre amplifier specially designed to amplify scar modes of a multimode chaotic optical fibre. More precisely, we introduce Ytterbium in the optical fibre as a gain medium localised on the maximum of intensity of the scar modes. After briefly recalling the relevance of a chaotic optical fibre as a device...

Ever extending applications of fiber lasers require energy efficient, high-power, small footprint and reliable fiber lasers and laser wavelength versatility. To meet these demands, next generation of active fibers for high-power fiber lasers is coming out that will eventually offer tailored spectroscopic properties, high robustness and reduced...

Si les fibres optiques multimodes à section transverse non circulaire constituent des laboratoires d'études privilégiés pour sonder les manifestations ondulatoires du chaos des rayons, ces dernìères conf èrent des propriétés singulìères aux modes de propagation. Nous montrons comment le contrôle des modes dans des fibres hautement multimodes...

A complete theoretical study of double-clad fiber amplifiers is proposed. The notion of chaotic propagation is taken into account in order to improve the pumping process. In addition, a space-time algorithm is used to optimize the distribution of rare-earth dopant in the double-clad fiber. Finally, computed gain curves versus wavelength show...

National audience

A multimode optical fiber with a D-shaped cross section is an experimental paradigm of a wave system with chaotic rays' dynamics. We show that seldom but usable modes, called scar modes, localized along some particular direction of the geometrical trajectories can be selectively excited. We report numerical simulations that demonstrate the...

Waves billiard which are chaotic in the geometrical limit are known to support non-generic spatially localized modes called scar modes. The interaction of the scar modes with gain has been recently investigated in optics in micro-cavity lasers and vertically-cavity surface-emitting lasers. Exploiting the localization properties of scar modes in...

Des systèmes simples, linéaires et conservatifs peuvent exhiber des dynamiques complexes du fait de leur géométrie. Le propos du chaos ondulatoire est d'étudier l'implication de ces dynamiques complexes sur le comportement des ondes[1]. Les fibres optiques hautement multimodes (les " f.o.h.m ") se révélent ainsi être de précieux supports...