Abstract: 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, a core (1), an inner cladding (2), a refraction index trench (3) and an outer cladding (4), wherein the core (1) includes a core radius R1, an alpha-refraction index profile and a core refraction index difference dn1 with respect to the outer cladding (4), wherein the refraction index trench (3) includes a refraction index trench radius R3 and a trench refraction index difference dn3 with respect to the outer cladding (4), wherein the outer cladding (4) includes an outer cladding radius R4 and a refraction index between 1.40 and 1.55, wherein for a light wavelength of 850 nm and a full core excitation (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 numeric aperture decreases by less than 2.

Abstract: The invention relates to an optical fiber, in particular a laser fiber, containing a doped glass fiber core (1) and cladding (2) 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 (3, 4, 5) 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.

Abstract: 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.

Abstract: 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 (1), an inner cladding (2), a refraction index trench (3) and an outer cladding (4), wherein the core (1) includes a core radius R1, an alpha-refraction index profile and a core refraction index difference dn1 with respect to the outer cladding (4), wherein the refraction index trench (3) includes a refraction index trench radius R3 and a trench refraction index difference dn3 with respect to the outer cladding (4), wherein the outer cladding (4) includes an outer cladding radius R4 and 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.

Abstract: An optical fiber has a core region, a cladding region and at least one spacer layer disposed between the core region and the cladding region. The core region is positively doped and has a positive refractive index with respect to the glass matrix of the optical fiber. The cladding region is negatively doped and has a refractive index of at most zero with respect to the glass matrix. The numerical aperture of the optical fiber is composed of variable proportions of the positively doped core region and the negatively doped cladding region and results from the refractive indices of both regions.

Abstract: A sensor fiber for the detection of changes of temperature, bending, and/or torsion includes a multicore optical waveguide with a fiber Bragg grating (FBG) structure. One embodiment contains at least two FBG cores and a surrounding cladding. The sensor fiber is characterized by one or more distinction and orientation means which produce a marker zone to assign and label each individual FBG core.

Abstract: Methods for making a preform for a graded-index multimode fiber by using an inside deposition process are disclosed. The methods are characterized by an iterative refractive index profile correction with the following steps: determining a target refractive index profile for the preform to be produced, carrying out an inside deposition process with fixed volume flows for the reacting gases inside a tube and a given burner speed for all deposited layers, collapsing the tube and measuring the actual refractive index profile, comparing the target profile with the actual profile and calculating a correction value of index differences, converting this correction value in corrected burner speeds as varying process parameter, carrying out a inside deposition process with fixed gas flows and corrected burner speeds for all layers to be deposited.

Abstract: Methods and devices for the production of glass fiber preforms are disclosed. The methods and devices are based on a modified chemical vapour deposition process wherein the reacting gases are reacted in a hot zone within a substrate tube. Glass layers are deposited by a first heating instrument moving with respect to the substrate tube. The reaction gases are subjected to a temperature treatment before entering the hot zone of the main burner to encourage an evenly distributed chemical reaction, deposition and doping concentration over the length of the substrate tube. This is based on the position of the substrate tube with respect to the heating instrument and the resulting different heating of the reaction gases.

Abstract: Methods for making active laser fibers include the production of an optical fiber with disturbed (or deviated) cylindrical symmetry on the glass surface of the fiber. The methods include a preform containing a central core made of glass. In one embodiment, the preform is circular and surrounded by additional glass rods and an outer glass jacket tube. In a first alternative embodiment, this preform is merged during fiber drawing. In a second alternative embodiment, the preform merged in a process forming a compact glass body with disturbed cylindrical symmetry. This compact preform is drawn into a fiber under conditions maintaining the disturbed cylindrical symmetry.

Abstract: 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 a numerical aperture that is uniform over its length, a core (1), an inner cladding (2), a refraction index trench (3) and an outer cladding (4), wherein the core (1) includes a core radius R1, an alpha-refraction index profile and a core refraction index difference dn1 with respect to the outer cladding (4), wherein the refraction index trench (3) includes a refraction index trench radius R3 and a trench refraction index difference dn3 with respect to the outer cladding (4), wherein the outer cladding (4) includes an outer cladding radius R4 and 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.

Abstract: A burner for the partial oxidation of liquid, carbonaceous fuel with steam and an oxygen-containing gas a well as the process in which this burner is used, wherein the parts of the outlet orifice of the burner directed towards the combustion chamber are wholly or partly provided with a coating or with a diffusion layer for protection against thermal load and/or corrosion.

Abstract: A reactor is described for the production of C2 to C8 olefins from gaseous oxygenate and H2O and one or more material flows containing C2 C4, C5, C6, C7, C8 olefin and paraffin at 400° to 470° C., wherein several reaction stages which the material flow can pass through from the top to the bottom, each consisting of a support base with a catalyst layer situated on it, are arranged in a closed, upright container.

Abstract: The invention relates to an optical waveguide and a semifinished product for producing an optical waveguide having optimized diffraction properties, comprising a trench structure that has a radius-dependent graded refractive index curve and/or a concentric depressed refractive index profile within a core zone (2) and/or within a cladding zone (4). In one embodiment of the optical waveguide and semifinished product, the structure is formed from a succession of differently doped regions containing dopants that are introduced into a base matrix and lower and/or increase the refractive index.

Abstract: The invention relates to an optical fiber, in particular a laser fiber, containing a doped glass fiber core (1) and cladding (2) 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 (3, 4, 5) 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.

Abstract: 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.

Abstract: The invention relates to a multi-nozzle, tubular plasma deposition burner (1) for producing preforms as semi-finished products for optical fibers, wherein a media stream containing glass starting material and a carrier gas is fed to the burner (1), means for feeding at least one dopant using at least one precursor gas and a substantially perpendicular orientation of the burner gas longitudinal axis relative to the center axis of the substrate (4). According to the invention, a first partial stream of a first gas or gas mixture, in particular a precursor gas, is fed to the plasma and to the substrate (4) by way of at least one nozzle running in the burner longitudinal axis and a second partial stream of the first gas or of another gas or gas mixture, in particular a precursor gas, is fed to the plasma and the substrate by way of another nozzle (5); said gases or gas mixtures are fed in such a way that said partial streams combine in the vicinity of the substrate.

Abstract: The invention relates to a reactor for the production of C2 to C8 olefins from gaseous oxygenate and H2O and one or more material flows containing C2 C4, C5, C6, C7, C8 olefin and paraffin at 400° to 470° C., wherein several reaction stages which the material flow can pass through from the top to the bottom, each consisting of a support base with a catalyst layer situated on it, are arranged in a closed, upright container.

Abstract: The burner has at least two fuel-carrying tubes which are arranged in parallel, the distance between adjacent fuel-carrying tubes being 5 to 30 cm. Each fuel-carrying tube is surrounded by a steam-carrying tube, which at its orifice end has a supply line for oxygen-containing gas. The steam-carrying tubes are surrounded by a common first cooling chamber through which cooling liquid is passed, the first cooling chamber constituting an annular chamber and extending into the area of the orifice ends of the steam-carrying tubes. Coaxial to the first cooling chamber a common second cooling chamber preferably is provided, which is surrounded by the first cooling chamber.

Abstract: A piston is provided which serves to produce a pressure surge in a wind tunnel. Under the action of a gas pressure of at least 20 bars the piston is propelled in a first passage from an initial position to a target surface. Under the compression produced by the approaching piston, a diaphragm disposed at the end of the first passage is torn. The resulting pressure surge is transmitted in a second passage, which is filled with a testing gas, to a thin sheet. That thin sheet is torn so that the testing gas can enter a testing chamber as a supersonic shock wave. The piston is provided at its rear end with a locking extension, which cooperates with a stationary holder when the piston is in its initial position.

Abstract: For collection of dust from gases at temperatures up to 900.degree. C. and under presssures up to 20 bars by means of gas-permeable two-dimensional filter elements, an apparatus is proposed which comprises a pressure-resisting cylindrical outer housing, which contains a gas-tight pear-shaped inner housing, which is movably mounted in the outer housing by a means of a heat-insulating carrying structure and is provided with a tubular gas-outlet port and comprises a cambered bottom, which contains cylindrical filter elements. A pressure-confining gas-tight compensator is provided between the tubular gas-outlet port of the inner housing and the outer housing. Because the "pressure-confining" and "supporting" functions are separate, the internal components, which will be subjected to temperatures up to 900.degree. C., can be joined to the pressure-confining wall of the outer housing, which must not be heated above 200.degree. C.