Abstract: A device for monitoring a process in laser material processing, comprising a laser generating a light beam, wherein the light beam may impinge on a lens matrix disposed between the light source and a beam splitter. The lens matrix may comprise microlenses, operable to generate a matrix of light beams from the impinging light beam. Part of the matrix of light beams may be directed to a mirror in a reference arm and part may be directed to an unknown surface in a measuring arm. The reflection of these beams may be used to generate an interference signal to be evaluated.

Abstract: A fiber coupler is provided, which includes a tubular enveloping structure and several optical fibers arranged in the enveloping structure, each of which has a fiber core and a fiber cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fiber core to the diameter of the fiber cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fiber to the diameter of the fiber core, increases in the first direction for each optical fiber.

Abstract: A fiber coupler is provided, which includes a tubular enveloping structure and several optical fibers arranged in the enveloping structure, each of which has a fiber core and a fiber cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fiber core to the diameter of the fiber cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fiber to the diameter of the fiber core, increases in the first direction for each optical fiber.

Abstract: A fiber coupler is provided, which includes a tubular enveloping structure and several optical fibers arranged in the enveloping structure, each of which has a fiber core and a fiber cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fiber core to the diameter of the fiber cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fiber to the diameter of the fiber core, increases in the first direction for each optical fiber.

Abstract: A fibre coupler is provided, which includes a tubular enveloping structure and several optical fibres arranged in the enveloping structure, each of which has a fibre core and a fibre cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fibre core to the diameter of the fibre cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fibre to the diameter of the fibre core, increases in the first direction for each optical fibre.