Various embodiments described include optical fiber designs and fabrication processes for ultra high numerical aperture optical fibers (UHNAF) having a numerical aperture (NA) of about 1. Various embodiments of UHNAF may have an NA greater than about 0.7, greater than about 0.8, greater than about 0.9, or greater than about 0.95. Embodiments of UHNAF may have a small core diameter and may have low transmission loss. Embodiments of UHNAF having a sufficiently small core diameter provide single mode operation. Some embodiments have a low V number, for example, less than 2.4 and large dispersion. Some embodiments of UHNAF have extremely large negative dispersion, for example, less than about −300 ps/nm/km in some embodiments. Systems and apparatus using UHNAF are also disclosed.

Ultra high numerical aperture optical fibers

Disclosed is a dispersion compensating optical fiber that includes a refractive index profile selected to provide dispersion at 1550 nm of between −90 and −150 ps/nm/km; dispersion slope at 1550 nm of less than −1.5 ps/nm 2 /km; and kappa of between 40 and 95. The profile preferably has a core surrounded by a cladding layer of refractive index Δ c , and at least three radially adjacent regions including a central core region having Δ1, a moat region having a refractive index Δ2, and an annular ring region having a refractive index Δ3, wherein Δ1>Δ3>Δc>Δ2.

Dispersion compensating optical fiber

Disclosed is a single mode optical waveguide fiber having alternating segments of positive and negative dispersion and dispersion slope. The relative indexes, the refractive index profiles and the radii of the segments are chosen to provide low total dispersion and dispersion slope. One embodiment consists of a first central major index profile (10) of outer radius r1, surrounded by a first annular segment (12) of outer radius r2, surrounded by second annular segment (14) of outer radius r3. Preferred waveguides in accordance with the invention exhibit a dispersion over the range of 1520 to 1625 nm which at all times have a magnitude which is less than 2, and more preferably less than 1 ps/nm2-km. The total dispersion of the waveguide fiber is in the range of about -2.0 to +2.0 ps/nm-km at 1550 nm. The waveguide also features a low polarization mode dispersion.

Low slope dispersion managed waveguide

Disclosed are refractive index profiles for total dispersion compensating optical waveguide fibers for use in high data rate, long length telecommunications systems. The optical waveguide fibers in accord with the invention provide substantially equal compensation of total dispersion over a range of wavelengths, thus facilitating wavelength division multiplexed systems. Also disclosed are spans of optical waveguide fiber that include a length of transmission fiber together with a length of the compensating fiber. The spans are joined end to end in series arrangement to form the optical waveguide fiber part of a telecommunication system.

Dispersion slope compensating optical fiber

A method for manufacturing optical fiber preform and fiber. According to the method, a core cane segment is formed with a refractive index delta preferably between 0.2% and 3% that is most preferably formed by an OVD method. A sleeve is formed including at least one down-doped moat preferably having a refractive index delta between −0.1% and −1.2% and at least one up-doped ring preferably having a refractive index delta between 0.1% and 1.2%. The sleeve is formed by introducing glass precursor and dopant compounds into a cavity of a preferably silica glass tube (e.g., one of an MCVD and PCVD method). The core cane segment is inserted into the sleeve and the sleeve is collapsed onto the core cane segment to form a core-sleeve assembly. The core-sleeve assembly is again drawn into a cane and additional cladding is preferably formed thereon. Optical fiber may be drawn from the preform in a conventional draw apparatus. According to another embodiment, the method of manufacturing a multi-segment optical fiber preform comprising the steps of forming a core cane including a first up-doped portion and a down-doped portion, forming a sleeve on an inside of a tube including a second up-doped portion, inserting the core cane into the sleeve, and collapsing the sleeve around the core cane to form a cane-sleeve assembly.

Method of manufacturing multi-segmented optical fiber and preform

Disclosed is a dispersion compensating optical fiber that includes a core surrounded by a cladding layer of refractive index nCL. The core includes at least three radially adjacent regions, a central core region, a moat region having a refractive index nM that is sufficiently lower than nCL such that ΔM ≤ -0.4 %, and a ring region. As the ring region exhibits sufficiently high refractive index at a sufficiently long distance from the outer edge of the moat region, the fiber can exhibit low values of negative dispersion slope at low values of negative dispersion and yet exhibit good bending loss. This ring region is also capable of imparting to the fiber a relatively high cutoff wavelength, so that the present invention is particularly well suited for use in L-band systems. A particularly suitable fiber has an index profile in which that part of the ring region at the transition between the moat and the ring region has a refractive index such that its delta value is close to zero. Also disclosed is a method of forming the fiber of the present invention.

Dispersion compensating fiber

L'invention concerne une fibre de compensation de la dispersion comprenant une âme entouree d'une couche de metallisation d'indice de refraction nCL. L'âme presente au moins trois zones radialement adjacentes, une zone âme centrale, une zone douve ayant un indice de refraction nM suffisamment inferieur a nCL de maniere que ΔM ≤ -0,4 % ainsi qu'une zone anneau. Comme la zone anneau fait preuve d'un indice de refraction suffisamment eleve a une distance suffisamment eloignee du bord externe de la zone douve, la fibre peut avoir des valeurs faibles de pente de dispersion negative a des valeurs faibles de dispersion negative, ce qui entraine une bonne perte par courbure. La zone anneau est aussi en mesure de conferer a la fibre une longueur d'onde seuil relativement elevee afin qu'elle s'adapte aux systemes a bande L. Une fibre particulierement adaptee est celle dont la partie de la zone anneau au niveau de la transition entre la zone douve et la zone annulaire a un indice de refraction tel que sa valeur delta est voisine de zero. L'invention concerne aussi un procede de formation de cette fibre.

Fibre de compensation de la dispersion

A method is disclosed for recovering germanium from a gaseous mixture which includes a germanium-containing compound in vapor or particulate form, acid in vapor form, and water vapor. The gaseous mixture is contacted with a liquid containing water under conditions effective to dissolve the germanium-containing compound in the liquid. The acidity of the resulting liquid mixture is increased under conditions effective to vaporize the germanium-containing compound. The vaporized germanium-containing compound is contacted with one or more aqueous solutions under conditions effective to dissolve and precipitate the germanium-containing compound in at least one of the one or more aqueous solutions, and the resulting precipitate is separated from the at least one of the one or more aqueous solutions. The methods described herein are particularly well suited for recovering germanium from the waste gases produced during optical waveguide manufacturing processes. Germanium recovered by this method can thereafter be used in the production of semiconductors, optical waveguide fibers and optical components.

Lei Jiang

Papers

Dispersion compensating fiber

Fibre de compensation de la dispersion

Methods for the separation of compounds from acidic aqueous solutions