Alcatel N.v.

Societe Anonyme Dite: Compagnie Generale D'electricite

Alcatel Cit

Alcatel Fibres Optiques

Jacques Auge

Herve Fevrier

Jean-Francois Marcerou

Claude Brehm

Pascale Nouchi

Jean-Michel Gabriagues

Jean-Yves Boniort

Emmanuel Grard

Daniel Mousseaux

Jean-Pierre Blondel

Eugene Duda

Jean-Jacques Guerin

Jean-Luc Beylat

Josiane Ramos

Jean-Claude Gacon

Henri Gagnaire

Olivier Mercereau

Bernard Jacquier

Pascale Beaufume

Bertrand Poumellec

Monomode optical fiber

A method of detecting variation in the diameter of an optical fiber includes the following steps:

Method of detecting variation in the diameter of an optical fiber and

A telecommunications system having erbium-doped fiber optical amplifiers for transmitting signals including at least one signal at a wavelength of about 1550 nm, wherein the amplifiers are fibers whose cores are doped with erbium and germanium and are free from aluminum; and wherein for each of the amplifiers, the length of the fiber and the pumping power which is injected therein are such that the noise generated by the fiber is generally emitted around 1550 nm. As can be seen in FIG. 4 , the signal-to-noise ratio remains satisfactory after 10,000 km of propagation without using an intermediate filter.

Telecommunications system having fiber optical amplifiers for

An erbium-doped fiber optical amplifier, characterized in that said fiber has a mode radius which is not greater than 2.7 .mu.m at a wavelength of 1.55 .mu.m, and in that it has at least one pump wavelength situated in the following regions of the spectrum: 0.98 .mu.m.+-.0.4 .mu.m and 1.48 .mu.m.+-.0.4 .mu.m; the region of the spectrum of at least one signal to be amplified being 1.5 .mu.m to 1.6 .mu.m.

Erbium-doped fiber optical amplifier

A DFB laser (2) is coupled to a monomode line fiber (14) via an isolator constituted by a Faraday rotator crystal (4) and a polarizing fiber (10) which is welded to a fiber to be coupled (14). A focusing lens (8) is integrated in an intermediate block including the rotator crystal (4) and a permanent magnet (6). The invention is particularly suitable for making light-emitting heads for use in optical fiber telecommunications systems.

Optical head with an integrated isolator for coupling a semiconductor

An optical fiber for frequency conversion, has an annular index profile structure for obtaining zero order phase matching and optimum overlap between the fibers's resonant propagation modes, one propagating the wave w and the other the wave kw where 2.ltoreq.k.ltoreq.4 for at least one wavelength lying in the range 0.4 .mu.m to 2.6 .mu.m, with the index step .delta.n in the ring lying in the range 2.times.10.sup.-2 and 5.times.10.sup.-2, the inside radius r.sub.i of the ring lying in the range 0.5 .mu.m to 1.5 .mu.m, and the outside radius r.sub.e of the ring lying in the range 2 .mu.m to 3.5 .mu.m.

Optical fiber for frequency conversion

The core (2) of a monomode fiber is surrounded by a slightly monomode annular waveguide (6) guiding masking light having the same wavelength as the light conveyed by the core. The invention is particularly suitable for telecommunications.

Monomode optical fiber with protection against tapping of transmitted

An erbium-doped fiber laser amplifier (1), characterized by the fact that said fiber (3) is doped to a concentration lying in the range 5 ppm to 50 ppm, that the length of said fiber lies in the range 250 m to 30 m depending on the selected concentration of doping, and that the radial position of the doped zone substantially coincides with the energy maximum of the set of propagation modes in said fiber at the pumping wavelength.

Doped optical fiber laser amplifier

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Saint Cheron, France

Jacques Auge