Abstract: The invention concerns an apparatus and its use for laser welding. A laser welding apparatus comprise at least one first laser device, each providing at least one first optical feed fiber with a first laser beam; at least one second laser device, each providing at least one second optical feed fiber with a second laser beam; means for generating a composite laser beam comprising a first output laser beam and a second output laser beam for welding a workpiece; wherein the first output laser beam has a circular cross-section and the second output laser beam has an annular shape concentric to the first output laser beam. The second laser device is a fiber laser device or a fiber-coupled laser device.

Abstract: The invention concerns an apparatus and its use for laser welding. A laser welding apparatus comprise at least one first laser device, each providing at least one first optical feed fiber with a first laser beam; at least one second laser device, each providing at least one second optical feed fiber with a second laser beam; means for generating a composite laser beam comprising a first output laser beam and a second output laser beam for welding a workpiece; wherein the first output laser beam has a circular cross-section and the second output laser beam has an annular shape concentric to the first output laser beam. The second laser device is a fiber laser device or a fiber-coupled laser device.

Abstract: An apparatus and its use for laser processing along with a method and an optical component. A first laser device provides a first optical feed fiber and a second laser device provides a second optical feed fiber. A beam combining means connected to the first and second feed fibers and to a multi-core optical fiber is adapted to form a composite laser beam by having the first optical feed fiber aligned with a first core of the multi-core optical fiber and the second optical feed fiber aligned with at least one second core of the multi-core optical fiber. The first and second cores outputs a composite laser beam to a workpiece to be processed. A control unit individually controls the power density of the output laser beams.

Abstract: The invention concerns an apparatus and its use for laser welding. A laser welding apparatus comprise at least one first laser device, each providing at least one first optical feed fiber with a first laser beam; at least one second laser device, each providing at least one second optical feed fiber with a second laser beam; means for generating a composite laser beam comprising a first output laser beam and a second output laser beam for welding a workpiece; wherein the first output laser beam has a circular cross-section and the second output laser beam has an annular shape concentric to the first output laser beam. The second laser device is a fiber laser device or a fiber-coupled laser device.

Abstract: A pump reflector for efficiently recycling unabsorbed pump radiation in a diode-pumped fiber laser includes a core for guiding a laser beam, a pump cladding, and a tapered capillary tube. Pump radiation is adiabatically guided in the tapered capillary tube, which includes a mirror that is reflective for the pump radiation. The pump reflector may be packaged as a fiber component for co-propagating or counter-propagating fiber laser amplifiers and resonators.

Abstract: The invention concerns an apparatus and its use for laser processing. The invention also concerns a method and an optical component. According to the invention, at a first laser device, providing a first optical feed fiber and a second laser device providing a second optical feed fiber is provided. A beam combining means connected to the first and second feed fibers and to a multi-core optical fiber is adapted to form a composite laser beam by having the first optical feed fiber aligned with a first core of the multi-core optical fiber and the second optical feed fiber aligned with at least one second core of the multi-core optical fiber. The first and second cores outputs a composite laser beam to a workpiece to be processed. A control unit individually controls the power density of the output laser beams.

Abstract: The invention relates to an optical assembly for producing such. The invention also relates to the use of the optical assembly. Laser radiation received via a bundle of individual optical feed fibers is guided to a fiber laser fiber. Each feed fiber has a cladding layer surrounding the core of the fiber to provide total internal reflection in said core, and the cladding layers of the fibers are fused at least partially together to form a zone containing the cores of the feed fibers arranged in a cylindrical configuration inside said zone This configuration provides the shaping of an annular laser beam that can be fed into a fiber laser fiber having an annular light guiding zone and to present the annular laser beam e.g. to a workpiece.

Abstract: The present invention provides a packaging for a fiber optic component, such as an optical fiber, wherein the heating induced strain to the fiber optic component is minimized, wherein the packaging comprises a first support member having a first coefficient of thermal expansion (k1). The packaging further comprises a second support member, which is resiliently mounted to the first support member for minimizing transfer of thermal expansion induced strain of the first support member to the second support member. The second support member comprises a longitudinal groove open at least on one side of the second support member for receiving a fiber optic component, wherein the second support member has a tensile strength considerably higher than that of the fiber optic component.

Abstract: The invention concerns a fiber-optic component, in particular a fiber coupler, and method for manufacturing thereof. The component comprises a housing (25), at least one first optical element (21) capable of guiding light and having an output end, the first optical element (21) being affixed to said housing (25) at a mounting zone (26A), and at least one second optical element (22, 23) optically coupled to the first optical element (21) at a coupling zone (27) for receiving light from the output end of the first optical element (21). According to the invention, the component comprises at least one zone (29) of light-scattering material arranged in the vicinity of the first optical element (21) at a region between the coupling zone (27) and the mounting zone (26A). By means of the invention, the effect potentially harmful reverse radiation in fiber-optic components can be mitigated.

Abstract: A fiber optic mode scrambler includes a multi-mode optical fiber formed with a core and a cladding around the core and a non-adiabatic cross-sectional shape change zone in the optical fiber. The fiber further has a bending region extending over a length of the optical fiber. The optical fiber has a non-zero curvature at the bending region and a device for maintaining the curvature of the optical fiber at the bending region. Mode scramblers can be provided that are accurately adjusted to match with different desired optical characteristics. A well-controlled manufacturing method for the mode scrambler is also described.

Abstract: A fiber optic mode scrambler includes a multi-mode optical fiber formed with a core and a cladding around the core and a non-adiabatic cross-sectional shape change zone in the optical fiber. The fiber further has a bending region extending over a length of the optical fiber. The optical fiber has a non-zero curvature at the bending region and a device for maintaining the curvature of the optical fiber at the bending region. Mode scramblers can be provided that are accurately adjusted to match with different desired optical characteristics. A well-controlled manufacturing method for the mode scrambler is also described.

Abstract: The present invention provides a packaging for a fiber optic component, such as an optical fiber, wherein the heating induced strain to the fiber optic component is minimized, where the packaging comprises a first support member having a first coefficient of thermal expansion (k1). The packaging further comprises a second support member, which is resiliently mounted to the first support member for minimizing transfer of thermal expansion induced strain of the first support member to the second support member. The second support member comprises a longitudinal groove open at least on one side of the second support member for receiving a fiber optic component, wherein the second support member has a tensile strength considerably higher than that of the fiber optic component.

Abstract: The invention concerns a fiber-optic component, in particular a fiber coupler, and method for manufacturing thereof. The component comprises a housing (25), at least one first optical element (21) capable of guiding light and having an output end, the first optical element (21) being affixed to said housing (25) at a mounting zone (26A), and at least one second optical element (22, 23) optically coupled to the first optical element (21) at a coupling zone (27) for receiving light from the output end of the first optical element (21). According to the invention, the component comprises at least one zone (29) of light-scattering material arranged in the vicinity of the first optical element (21) at a region between the coupling zone (27) and the mounting zone (26A). By means of the invention, the effect potentially harmful reverse radiation in fiber-optic components can be mitigated.

Abstract: The invention relates to a pump coupler (2) and a manufacturing method. The pump coupler (2) comprises a least one signal fiber (50) for outputting optical energy, multiple pump fibers (31) for inputting optical energy into the signal fiber (50), and a coupling structure (40) for coupling the optical energy of the pump fibers (31) into the signal fiber (50). A signal feed-through fiber (32) goes through the coupling structure (40). In accordance with the invention the coupling structure (40) is a tapering capillary tube (40) having a first wide end (65) and a second narrow end (70), the pump fibers (31) are connected to the wide end of the capillary tube (40), and at least the narrow end (70) of the capillary tube (70) is collapsed around the signal fiber (32).

Abstract: An active multimode optical fiber consisting of a first core section (11), a thin barrier layer (12) material having a thickness (d2) and a lower refractive index than that of the first core section by an index difference (?n), a second core section (13) having a refractive index equal or higher than that of the first core section, and a cladding (14) having an index lower than that of the first core section. Said index difference and said thickness are selected so that a fundamental core mode couples less strongly with said cladding modes than higher order core modes. A scheme of changing the symmetry of the fiber for reduced sensitivity of the fundamental mode of the first core section to resonance effects.

Abstract: The invention relates to an optical fiber combiner and a method for the manufacture thereof. The combiner has a tapering support preform with a plurality of capillary bores, a plurality of input fibers including a core and a cladding around the core and being arranged in parallel in the capillary bores of a support preform, and an output fiber coupled to the tapered end of the support preform in optical connection with the input fibers. The cladding thickness to core thickness ratio of at least one of the input fibers is decreased at the region of the support preform. The invention provides an optically high quality fiber combiner.

Abstract: The invention relates to a pump coupler (2) and a manufacturing method. The pump coupler (2) comprises a least one signal fiber (50) for outputting optical energy, multiple pump fibers (31) for inputting optical energy into the signal fiber (50), and a coupling structure (40) for coupling the optical energy of the pump fibers (31) into the signal fiber (50). A signal feed-through fiber (32) goes through the coupling structure (40). In accordance with the invention the coupling structure (40) is a tapering capillary tube (40) having a first wide end (65) and a second narrow end (70), the pump fibers (31) are connected to the wide end of the capillary tube (40), and at least the narrow end (70) of the capillary tube (70) is collapsed around the signal fiber (32).

Abstract: The invention relates to a pump coupler (2) and a manufacturing method. The pump coupler (2) comprises a least one signal fiber (50) for outputting optical energy, multiple pump fibers (31) for inputting optical energy into the signal fiber (50), and a coupling structure (40) for coupling the optical energy of the pump fibers (31) into the signal fiber (50). A signal feed-through fiber (32) goes through the coupling structure (40). In accordance with the invention the coupling structure (40) is a tapering capillary tube (40) having a first wide end (65) and a second narrow end (70), the pump fibers (31) are connected to the wide end of the capillary tube (40), and at least the narrow end (70) of the capillary tube (70) is collapsed around the signal fiber (32).

Abstract: The invention relates to a saturable absorber structure (10) with multiple-layer epitaxial heterostructure absorbers. Typically the structure comprises first absorber layers of a quantum well semiconductor QW-material, which has a nonlinearly on radiation intensity dependent optical absorption; first contacting layers of a first optically transparent semiconductor material against a surface or surfaces of said first absorber layers; and a first Bragg-reflector (23). The first contacting layers have lattice fit or pseudomorphism with said first absorber layers. The absorber layer (13, 13a, 13b) of the QW-material has a thickness (S) of at maximum 60 nm.

Abstract: A method for preparing stents, with a stent blank subjected to a work process, in which the desired pattern is cut through the stent blank by evaporating the stent material with a diode-pumped fibre laser. The used fibre laser is preferably a picosecond laser having a minimum power of 20 W and a repetition frequency above 1 MHz.