Alcatel

Draka Comteq B.v.

Alcatel Fibres Optiques

Alcatel N.v.

Alcatel Alsthom Compagnie Generale D'electricite

Alcatel Submarcom

Alcatel Lucent

Avanex Corporation

Alcatel Cable France

Draka Comteo B.v.

Alcatel Fibers Optiques

Pierre Sansonetti

Isabelle Riant

Pierre Sillard

Denis Molin

Pascale Nouchi

Jose Chesnoy

Olivier Audouin

Jean-Pierre Hamaide

Fatima Bakhti

Andre Tardy

Carlos Luis De Barros

Claude Brehm

Lionel Provost

Jean-Yves Boniort

Louis-Anne De Montmorillon

Michel Sotom

Philippe Chanclou

Jean-Michel Gabriagues

Laurent Gasca

Amaury Jourdan

Michel Jurczyszyn

Franck Bruyere

Christine Moreau

Sébastien Bigo

Laurent Berthelot

Jean-Louis Auguste

Jean-Marc Blondy

Sébastien Fevrier

Francedillaois Gonthier

Serge Artigaud

Frederic Gerome

Guy Soulage

Jean Hervo

David Macia

Jean Guillon

Cyril Ruilier

José Chesnoy

A hybrid optical fiber integrates features of multimode optical fibers and single-mode optical fibers. The hybrid optical fiber possesses an optical core having a first core region and a second core region to provide improved optical mode coupling ratio for single-mode transmission while maintaining a broad bandwidth for multimode transmission. The hybrid optical fiber's optical core may optionally include a depressed trench positioned between the optical core's first core region and the optical core's second core region to reduce modal dispersion and to improve modal bandwidth during multimode transmissions.

Hybrid single-mode and multimode optical fiber

It is proposed a home optical data network formed of an optical fiber comprising an optical core and an optical cladding surrounding the optical core, the optical core having a refractive graded-index profile with a minimal refractive index nand a maximal refractive index n, said optical fiber being such that it has a numerical aperture NA and an optical core radius a satisfying a criterion C of quality of optical communications defined by the following equation: &#x394; is the normalized refractive index difference,and in that said minimal and maximal refractive indexes n, nand said optical core radius a are chosen such that NA&#x3e;0.20, a&#x3e;10 &#x3bc;m and |C|&#x3c;0.20.

High bandwidth multimode optical fiber optimized for multimode and single-mode transmissions

It is proposed an optical fiber including an optical core and an optical cladding surrounding the optical core. The optical core has a refractive graded-index profile with a minimal refractive index nand a maximal refractive index n. The optical fiber has a numerical aperture NA and an optical core radius &#x3b1; satisfying a criterion C of quality of optical communications defined by the following equation:=NA&#x2212;0.02&#xd7;  The minimal and maximal refractive indexes n, nand the optical core radius a are chosen such that NA&#x3e;0.20, a&#x3e;10 &#x3bc;m and |C|&#x3c;0.20.

An in-fiber mode converter comprises fiber portions () constituting an input microlens, a fiber portion () constituting a phase shifting region adapted to convert a propagation mode of an optical signal into another propagation mode, and fiber portions () constituting an output microlens. The fiber portions are spliced, the converter is compact and losses are minimized relative to mode conversion in free space.

Mode converter

An optical module for chromatic dispersion compensation comprises an optical fiber wound so as to present a variable radius of curvature. The fiber has an index profile such that it has, for the main propagation mode, a negative dispersion value having a minimum at a given wavelength in a given spectral band. The value and the spectral position of the dispersion minimum vary with the radius of curvature of the fiber. The module allows the introduction of a large chromatic dispersion compensation value overall of a given spectral band, as well as compensation corrections for specific wavelengths inside the given spectral band.

Chromatic dispersion compensation module

The invention relates to an optical fiber presenting a core, cladding, and a grating written by irradiation and coupling at least one light mode into the cladding so that it is dissipated therein. The invention proposes causing the mean index to vary progressively along the grating, at least at the ends of the grating. The progressive variation in mean index or in the amplitude of index modulation for writing the grating serves to limit insertion losses to the filter formed by the grating. Analogously, in a written-in grating, the invention provides the equivalent of progressively varying the core size of the fiber for interconnecting two optical fibers presenting different core diameters. The invention is applicable in particular to gain-equalizing filters in WDM transmission systems.

Reducing insertion losses of a written in grating with mode coupling in the cladding

The fiber is adapted to compensation of the chromatic dispersion and chromatic dispersion slope of an optical fiber with negative chromatic dispersion. It has, in a propagation mode other than the fundamental mode, a positive chromatic dispersion and a negative chromatic dispersion slope. The fiber can be used in compensation dispersion modules or as line fiber, in transmission systems using line fiber with negative chromatic dispersion.

Fibre for compensation of the cumulative chromatic dispersion in a fibre with negative chromatic dispersion

The invention relates to polarization mode dispersion; writing index variations in a grating written in an optical fiber generates polarization mode dispersion. The invention proposes to compensate this polarization mode dispersion by mechanical curvature of the fiber. The invention provides a simple method of compensating polarization mode dispersion effectively and improving the performance of a grating written in a fiber; it applies in particular to Bragg gratings.

Compensation of polarization mode dispersion of a grating written in an optical fiber

The line optical fiber of the system is single-mode and has a very large effective mode area accompanied by high chromatic dispersion and/or a steep spectrum gradient of said dispersion. Compensation means are associated with said fiber so as to compensate at least a major portion of said dispersion and/or of said gradient. They are integrated into repeater units distributed along the transmission line. The invention applies to telecommunications.

Method, a system, and a line for optical fiber transmission

An optical filter has little variation in chromatic dispersion over its passband, the filter being constituted by a Bragg grating whose pitch varies as a function of distance along the filter with a change in the sense of its concavity. The filter also presents apodization, e.g. apodization by a super-Gaussian function or Blackman apodization. The filter of the invention is adapted to high data rate dense WDM transmission systems.

Optical filter with little variation in chromatic dispersion

The invention proposes a photosensitive optical fiber for inscribing a Bragg grating by UV illumination, in which the photosensitivity is very high either to reduce the exposure time or to increase the contrast of the optically induced refraction index variations, whilst retaining a reasonable exposure time. Thanks to this high contrast, the fiber of the invention, imprinted with a linear chirp, in addition to correcting chromatic dispersion, is also effective in correcting the chromatic dispersion slope of a fiber of ordinary contrast, imprinted with a quadratic chirp. In a preferred embodiment, the fiber of the invention is photosensitive in the cladding. In a particularly advantageous embodiment, a non-photosensitive dopant is added to the core of said fiber to reduce the refractive index in the core, reducing the birefringence of the fiber.

Photosensitive optical fiber for a bragg grating filter, a method of fabricating said fiber, and a chromatic dispersion and chromatic dispersion slope compensator including a fiber of this kind

The invention relates to the field of optical fiber wavelength division multiplexed transmission, and more particularly to the field of narrow-band optical filters for dense multiplexing. The invention proposes a narrow-band optical filter with a group-delay response that is very flat in the working band, obtained by cascading two Bragg gratings having group delays that are linear as a function of wavelength in the working band, but with their gradients being of opposite signs. The present solution is easier and less costly to implement than the prior art solutions, and it should also offer higher performance.

Fiber Bragg grating optical filter with a constant group-delay response in its working band

Dispersion-shifted monomode optical fibers have an effective mode surface area greater than 65 &mgr;m by optimization of the geometrical characteristics that characterize the fibers.

Dispersion-shifted monomode optical fiber

An angled Bragg grating optical waveguide section adjusts the spectral response of a transmission filter in an optical waveguide or in an optical fiber. To smooth the response of the filter, which is subject to modulation due to coupling to the various cladding modes, the pitch of the Bragg grating is caused to vary in a linear fashion along the length of the filter. To adapt the attenuation band to a required band, the cladding of the optical fiber is doped with a photosensitive material so that the grating is also formed in the cladding. The photosensitivity of the cladding is advantageously greater than that of the core, in a ratio in the order of 5:1.

Filter optical waveguide with inclination and linear chirp

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Palaiseau, France

Pierre Sansonetti