Laurent Gasca

Efficient Bragg gratings in phosphosilicate and germanosilicate photonic crystal fiber

We present ArF laser-induced dynamics of Bragg grating (BG) growths in phosphosilicate-doped or germanosilicate-doped core photonic crystal fibers (PCFs). To this end, we have adapted the technique of H2 loading, usually used in conventional fiber, to the case of microstructured fiber, allowing both the concentration of hydrogen in the PCFs to be kept nearly constant for the time of the exposure and the BG spectra to be easily recorded. We compared the characteristics of BG growths in the two types of PCF to those in conventional step-index fibers. We then conducted a study of the thermal stability of the BGs in PCFs through 30 min of isochronal annealing. At the same time we discuss the role played by the microstructuration and the doping with regard to the grating contrast and the Bragg wavelength stability.

Nanoparticle Doping Process: towards a better control of erbium incorporation in MCVD fibers for optical amplifiers

Germano-silica and alumino-silica Erbium Doped Fibers have been fabricated through a new Nanoparticles Doping process with MCVD technology. These fibers have been characterized in WDM amplification experiments in both C and L band.

Test of photonic crystal fiber in broadband interferometry

Photonic crystal fibers (PCFs) are microstructured waveguides that are used in metrology, nonlinear optics, and coherent tomography. PCF studies are focused mainly on the improvement of dispersion properties and wide spectral single-mode operating domains. Consequently, in the astronomical context this kind of fiber is a good candidate for use in the design of a fiber-linked version of a stellar interferometer for aperture synthesis. We discuss the potential of these fibers to take advantage of wide spectral single-mode operation. We propose an experimental setup that acts as a two-beam interferometer that uses PCFs to measure fringe contrast at four wavelengths (670, 980, 1328, and 1543 nm), which correspond to the R, I, J, and H astronomical bands, respectively, with the same couple of PCFs. For this purpose we use, for the first time to our knowledge, a piezoelectric PCF optical path modulator.

Full vector modal analysis of microstructured optical fiber propagation characteristics

Microstructured optical fibers (MOFs) are optical fibers having a periodic air-silica cross-section. The air holes extend along the axis of the fiber for its entire length. The core of the fiber is formed by a missing hole in the periodic structure. Remarkable properties of MOFs have recently been reported. This paper presents new work in the modeling of the propagation characteristics of MOFs using the Finite Element Method (FEM) and the Galerkin Method (GM). This efficient electromagnetic simulation package provides a vectorial description of the electromagnetic fields and of the associated effective index. This information includes accurate determination of the spectral extent of the modes, cutoff properties and mode-field distributions. We show that FEM is well adapted for describing the fields at abrupt transitions of the refractive index while GM has the advantage to accurately analyze MOFs of significant complexity using only modest computational resources. This presentation will focus on the specific techniques required to determine single mode operation, dispersion properties and effective area through careful choice of the geometrical parameters of the fibers. We demonstrate that with suitable geometrical parameters, the zero dispersion wavelength can be shifted. This tool can also provide design criteria for fabricating MOFs and a corresponding map of effective area. This approach is validated by comparison with experimental results and measurements on actual MOFs fabricated at IRCOM and at Alcatel Research and Innovation Center.

30dBm output power from a cladding pumped Yb free EDFA for L band applications

Several terabit/s per fiber are now regularly demonstrated [1] and will be commercially available soon. These high bit rates are achieved with wavelength-division-multiplexed (WDM) systems. The channels are located in both C-band (from λ = 1529nm to λ = 1561 nm) and L-band (λ = 1570nm to λ = 1603nm) windows. To increase the spans between amplifiers, it is still necessary to increase the power per-channel, which may result in high total amplifier output powers.

Dispersion-managed fiber with low chromatic dispersion slope

A dispersion-balanced fiber exhibiting a low chromatic dispersion slope (<0.015 ps/nm/sup 2//km at 1550 nm) was obtained by longitudinally changing the radial dimension of a refractive index profile. We report theoretical and experimental results and trade-offs between effective-area and cable ability aspects.

Highly Erbium-Doped Fibers Characterization and Modeling for Erbium Doped Fiber Amplifiers in WDM Regime

Simple experiments are used to determine ion-pairs percentage and macroscopic homogeneous upconversion in highly erbium-doped fibers. Using these parameters in a Giles-based model enable to predict Optical-Power-Conversion-Efficiency of WDM-EDFAs with a fair agreement.

Erbium Doped Fibre for Spectrally Wide and Flat Gain EDFA: Past and Future Developments

Erbium doped fibre is key element in developing Erbium Doped Fibre Amplifier with spectrally wide and flat gain for WDM applications. This paper will describe the progress made since the start and new improvement routes.

La fibre optique : retour sur 50 ans de développement. Où en sommes-nous aujourd’hui ?

REE N°1/2015 99 CÂBLES ET INFRASTRUCTURES OPTIQUES DOSSIER 2 Introduction Apres un bref historique du deve- loppement des fibres optiques pour les telecommunications et des differents types de fibres monomodales qui y ont ete associes, cet article presente plus en detail les deux grands types de fibres utilises pour le reseau terrestre et en particulier les reseaux d’acces, le mar- che de la fibre optique monomodale et son evolution. Les technologies asso- ciees a la fabrication de la fibre optique seront decrites, ainsi que les dernieres innovations apportees par les fibres optiques insensibles a la courbure et le developpement de nouveaux types de câbles a fibres optiques et de solutions de deploiement developpees et mises en œuvre par Prysmian Group. La revolution de la fibre optique a de- marre il y a maintenant presque 50 ans, et, depuis, a permis celle de la societe de l’information. C’est en effet en 1966 que K. C. Kao et G.A. Hockham [1] pre- disent que des pertes de 20 dB/km peuvent etre obtenues dans les fibres optiques en les purifiant suffisamment, apportant un avantage decisif par rap- port aux solutions a câble coaxial ou

Des produits innovants : fibres, câbles, connectivité pour des infrastructures FTTH performantes et pérennes

REE N°1/2015 111 CÂBLES ET INFRASTRUCTURES OPTIQUES DOSSIER 2 Introduction A partir des annees 1970, la DGT1 a construit en France un reseau de distri- bution qui a permis d’amener une ou deux paires de cuivre par foyer afin de disposer partout d’une ligne telepho- nique fixe. Le sous-equipement tele- phonique n’etait plus alors qu’une histoire lointaine, la France avait large- ment rattrape son retard, voire depasse, dans ce domaine, de nombreux pays industrialises. Ce chantier fut d’une ampleur exceptionnelle, necessitant de tres importants travaux de genie civil, en particulier dans les villes, la produc- tion et l’installation de plus de 15 mil- lions de poteaux, et aussi la construction d’usines pour la production de conduites souterraines en PVC, de câbles cuivre et d’accessoires. Apres l’installation de plus de 150 millions de kilometres de paires symetriques, la France s’est trou- vee dotee d’un reseau de cuivre parfai- tement homogene sur l’ensemble du territoire quels que soient la region, le departement, le canton ou la commune. Ce reseau passif, construit a partir de composants bien specifies et qualifies a permis,