Varying beam parameter product of a laser beam
AssigneesLumentum Operations LLC, Amada Holdings Co., Ltd.
InventorsMartin H. Muendel, Dahv Kliner
Life of this patent
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Abstract
An optical delivery waveguide for a material laser processing system includes a small lens at an output end of the delivery waveguide, transforming laser beam divergence inside the waveguide into a spot size after the lens. By varying the input convergence angle and/or launch angle of the laser beam launched into the waveguide, the output spot size can be continuously varied, thus enabling a continuous and real-time laser spot size adjustment on the workpiece, without having to replace the delivery waveguide or a process head. A divergence of the laser beam can also be adjusted dynamically and in concert with the spot size.
Claims42
An optical device for varying a beam parameter product of a laser beam, the optical device comprising:
- an input port for inputting the laser beam into the optical device;
- a beam launcher optically coupled to the input port;
- and
- an optical waveguide subassembly optically coupled to the beam launcher, the optical waveguide subassembly comprising
- an optical waveguide having first and second ends, a core, and a cladding surrounding the core, the core and the cladding extending between the first and second ends of the optical waveguide, and
- an exit lens coupled to the second end;
- wherein the beam launcher is configured for launching the laser beam at a convergence angle and a launch angle into the core of the optical waveguide at the first end of the optical waveguide, wherein the beam launcher is configured for varying one or more of the convergence angle and the launch angle;
- wherein in operation, the launched laser beam propagates from the first to the second end of the optical waveguide and through the exit lens, forming a first laser beam waist proximate the exit lens, the first laser beam waist having a diameter,
- wherein a distribution of local ray angles at the second end of the optical waveguide is substantially rotationally symmetric about an optical axis of the optical waveguide proximate the second end, and
- wherein, when the beam launcher varies the convergence angle or the launch angle, the diameter of the first laser beam waist is varied, thereby varying a beam parameter product of the laser beam exiting the exit lens.
An optical device for varying a beam parameter product of a laser beam, the optical device comprising:
- an input port for inputting the laser beam into the optical device;
- an optical waveguide subassembly optically coupled to the input port, the optical waveguide subassembly comprising an optical waveguide having first and second ends and an exit lens coupled to the second end;
- and
- a divergence adjusting element coupled to the optical waveguide between the first and second ends thereof, for adjusting a divergence of the laser beam inside the optical waveguide, thereby varying a waist diameter or a divergence of the laser beam exiting the exit lens, thereby varying a beam parameter product of the laser beam exiting the exit lens.
A method for varying a beam parameter product of a laser beam, the method comprising:
- providing an optical waveguide having first and second ends, a core, and a cladding surrounding the core, the core and the cladding extending between the first and second ends of the optical waveguide, and an exit lens coupled to the second end;
- launching the laser beam at a convergence angle or at a launch angle into the first end of the optical waveguide;
- propagating the launched laser beam in the optical waveguide from the first end to the second end, so as to enable ray angles of the laser beam guided by the optical waveguide to form a substantially rotationally symmetric distribution at the second end, while substantially preserving a distribution of magnitudes of local ray angles with respect to an optical axis of the optical waveguide;
- directing the laser beam through the exit lens, forming a first laser beam waist in the laser beam exiting the exit lens, wherein the first laser beam waist is substantially rotationally symmetric due to a rotational symmetry of the ray angles at the second end of the optical waveguide;
- and
- varying the convergence angle or the launch angle, to vary a beam parameter product of the laser beam exiting the exit lens.
Dependencies are inferred from the claim text.