Abstract: A method for producing a preform for producing a multi-core fiber. The method includes removing a first part-tube segment having a first part-tube segment cross-sectional area from a center of a receiving tube having a receiving tube internal diameter so that the receiving tube has a first core rod receiving cut-out, axially introducing a central filling rod having a filling rod external diameter into the receiving tube so that the receiving tube contains the central filling rod, inserting a first core rod having a first core rod cross-sectional area into the core rod receiving cut-out so that the receiving tube contains the core rod, axially introducing the receiving tube containing the first core rod and the central filling rod into a jacketing tube so as to obtain a jacketing tube containing the receiving tube, and fusing the jacketing tube containing the receiving tube to form the preform.

Abstract: A preform manufactured by a method which includes removing a part-tube segment from a center of a receiving tube so that the receiving tube has a core rod receiving cut-out which is formed as a remaining annular sector with two opposite edges, axially introducing a central filling rod into the receiving tube so that the receiving tube contains the central filling rod, inserting a core rod in a radial direction from outside into the core rod receiving cut-out between the two opposite edges of the remaining annular sector so that the receiving tube contains the first core rod, axially introducing the receiving tube containing the core rod and the central filling rod into a jacketing tube so as to obtain a jacketing tube containing the receiving tube, and fusing the jacketing tube containing the receiving tube to form the preform.

Abstract: The invention relates to a method and a device for producing a preform for glass fiber production. The method comprises the steps of providing a carrier gas with a desired, precisely adjusted temperature, loading the carrier gas with halide vapor, mixing the loaded carrier gas with additional gases, and producing the preform in a reaction chamber with substrate.

Abstract: A device for coating a fiber includes a fiber receiving arrangement and a coating arrangement which includes an application unit which wets the fiber with a coating agent, and a curing unit arranged downstream of the application unit which optically cures the coating agent. The curing unit includes a lamp which emits at least one light beam which is aimed directly or indirectly at a surface of the fiber. A main radiation direction of the lamp includes a beam angle between the main radiation direction and a longitudinal direction of the fiber of less than 40°. The fiber receiving arrangement and the application unit are movable relative to each other in the longitudinal direction of the fiber via a translational motion arrangement so that a wetting process is implemented substantially along an entire length of the fiber.

Abstract: A method for a defined deposition of a glass layer on an inner wall of a preform for an optical fiber and/or for setting a refractive index profile of the preform for a multi-mode fiber. The method includes providing the preform having a cavity and an inner wall which defines an inner diameter of the preform, and spreading a deposition gas at a flow speed (v) in the cavity of the preform so as to provide the defined deposition of the glass layer. The defined deposition is performed at a reduced change in the flow speed a*?v, where a<1. Based on the defined deposition, a change in the flow speed (?v): ? ? ? v = 4 ? ? Q ? · ( 1 d i 2 - 1 d i + 1 2 ) forms at a volume flow (Q), a first diameter (di), and a second diameter (di+1).

Abstract: A method for a defined deposition of a glass layer on an inner wall of a preform for an optical fiber and/or for setting a refractive index profile of the preform for a multi-mode fiber. The method includes providing the preform having a cavity and an inner wall which defines an inner diameter of the preform, and spreading a deposition gas at a flow speed (v) in the cavity of the preform so as to provide the defined deposition of the glass layer. The defined deposition is performed at a reduced change in the flow speed a*?v, where a<1. Based on the defined deposition, a change in the flow speed (?v): ? ? ? v = 4 ? ? Q ? · ( 1 d i 2 - 1 d i + 1 2 ) forms at a volume flow (Q), a first diameter (di), and a second diameter (di+1).

Abstract: 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.

Abstract: A device for coating a fiber includes a fiber receiving arrangement and a coating arrangement which includes an application unit which wets the fiber with a coating agent, and a curing unit arranged downstream of the application unit which optically cures the coating agent. The curing unit includes a lamp which emits at least one light beam which is aimed directly or indirectly at a surface of the fiber. A main radiation direction of the lamp includes a beam angle between the main radiation direction and a longitudinal direction of the fiber of less than 40°. The fiber receiving arrangement and the application unit are movable relative to each other in the longitudinal direction of the fiber via a translational motion arrangement so that a wetting process is implemented substantially along an entire length of the fiber.

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: 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: 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.

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: 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: 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.