J-fiber Gmbh

Leoni Kabel Gmbh

Fibercore Limited

Wolfgang Hämmerle

Lothar Brehm

Christian Genz

Matthias Auth

Falk Wirth

Mohd Aslami

Dau Wu

Robert Hanf

Jörg Kötzing

Mikhail I Guskov

Elke Poppotz

Harald Hein

Thomas Gutsche

Eugenie B Danilov

Elke Poppitz

Hans Engler

The invention relates to a method for producing a glass-fibre preform with a core of a polygonal cross section by using a rod-in-tube method and comprising the method steps of: providing a core rod () of a polygonal core rod cross section (), producing a sectored sandwich tube () from a starting tube (), wherein the lateral surface of the starting tube () is slit in the longitudinal direction into a series of outer segments (), and so the tube cross section of the starting tube () is subdivided into a series of sectors of a circle (), inserting the core rod () into the sectored sandwich tube () and aligning it and, in the case of one embodiment, inserting the core rod () and the sectored sandwich tube () into an outer casing tube () with a complete annular cross section and melting the sectored sandwich tube () and possibly the outer casing tube () onto the sectored sandwich tube (), wherein the outer segments () of the sectored sandwich tube () are fused to the respective side surfaces () of the core rod ().

Method for producing a glass-fibre preform with a core of a polygonal core cross section

The invention relates to a method for producing a polarization-maintaining optical fiber, consisting of a core region and stress-generating elements embedded in the fiber body, having the following method steps: producing a core preform for the core region using internal deposition on a substrate tube, the internally coated substrate tube subsequently being collapsed, generating recesses on the core preform by virtue of the material on the outer surface of the core preform being removed parallel to the longitudinal axis of the core preform at diametrically opposed positions, filling the recesses with stress-generating rods, with the tightest possible rod packing, in a freely selectable first filling geometry, possibly filling the recesses in addition with non-stress-generating rods in a second filling geometry, sheathing the filled core preform with a jacketing tube, preparing the sheathed core preform for a fiber-drawing process, and drawing the sheathed arrangement to form the optical fiber. A preform for producing a polarization-maintaining optical fiber contains a core preform, having a core region and a lateral region, and also contains a jacketing tube, which encloses the core preform, as well as stress-generating elements contained in the lateral region, wherein the stress-generating elements are provided in the form of recesses in the lateral region, wherein the recesses are filled with doped rods and/or undoped rods, and wherein the rod filling forms a first and/or a second arrangement geometry.

Polarization-maintaining optical fibre and preform and method for producing the same

The invention relates to a bend insensitive gradient index multi-mode light conducting fiber comprising a leakage mode dependent optical core diameter that is uniform over its length and a numerical aperture that is uniform over its length, wherein for a light wavelength of 850 nm and an overfilled launch (OFL), the optical core diameter for a fiber length in a range between 2 m and 100 m decreases by less than 5% and the numerical aperture decreases by less than 2.5% and the curvature related attenuation increase for two turns and a curvature radius of 7.5 mm is less than 0.2 db.

Bend insensitive gradient index multi-mode light conducting fiber

The invention relates to an optical fiber, in particular a laser fiber, containing a doped glass fiber core () and cladding () around the latter with a refraction index profile which decreases outwards from the fiber core. The optical fiber is distinguished by at least one intermediate layer () being disposed between the glass fiber core and the cladding to reduce the mechanical tension therebetween. In one advantageous embodiment, the intermediate layer is doped in such a way as to ensure a stepped mechanical tension distribution between the glass fiber core and the cladding, and is co-doped in such a way as to reduce the refractive index and counteract the refraction index-increasing effect of the intermediate layer doping. The invention further relates to an application of at least one doped barrier layer to a core region during preparation of the preform to avoid diffusion of special core dopants from the core during the collapse process, and to allow the diffusion of special dopants between the barrier layer and the core layer.

Optical fiber, in particular a laser fiber containing a doped glass fiber core and cladding around the fiberglass core

The invention relates to a bend insensitive gradient index multimode light conducting fiber comprising a leakage mode dependent optical core diameter that is uniform over its length and numerical aperture that is uniform over its length, a core (), an inner cladding (), a refraction index trench () and an outer cladding (), wherein the core () includes a core radius R, an alpha-refraction index profile and a core refraction index difference dnwith respect to the outer cladding (), wherein the refraction index trench () includes a refraction index trench radius Rand a trench refraction index difference dnwith respect to the outer cladding (), wherein the outer cladding () includes an outer cladding radius Rand a refraction index between 1.40 and 1.55, wherein for a light wavelength of 850 nm and an overfilled launch (OFL), the optical core diameter for a fiber length in a range between 2 m and 300 m decreases by less than 5% and the numerical aperture decreases by less than 2.5% and the curvature related attenuation increase for two turns and a curvature radius of 7.5 mm is less than 0.2 db.

A method for producing a glass fiber, through longitudinally drawing a preform in a drawing kiln, wherein cooling the glass fiber is performed in at least three time periods, wherein the glass fiber is exposed to a first time based cooling rate above a crystallization temperature range, to a second time based cooling rate that is greater than the first time based cooling rate within the crystallization temperature range, and to a third time based cooling rate which is smaller than the second time based cooling rate below the crystallization temperature range.

Method for producing a glass fiber and device

A method and apparatus for making optical fiber preforms using simultaneous plasma deposition on the inside and outside surface of a starting tube. A starting tubular member is rotated, CFOT chemicals are selectively injected into the plasma torch, and CFIT chemicals are selectively injected to flow through the hollow of the tube. The plasma torch is traversed along the tubular member to simultaneously deposit soot on the inside and outside surface. The soot on one or both surfaces may be consolidated into a silica layer as it is deposited. The plasma torch is traversed again to deposit additional soot, and/or consolidate previously deposited soot, on one or both surfaces. The process is repeated until a predetermined amount of silica is formed on the tubular member. The tubular member is then collapsed. Optionally, additional plasma deposition is performed during or after the collapsing.

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Jena, Germany

Wolfgang Hämmerle