Multi-wavelength adjustable-radial-mode fiber laser
AssigneeNufern
InventorsPeyman AHMADI, Peter Andrew ROSENTHAL
Life of this patent
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Abstract
A high-power fiber laser produces a compound output beam having a center beam and an annular beam. The center beam and the annular beam are independently adjustable in power and wavelength. The output beam is delivered from an output optical fiber having a center core and a concentric annular core. A fundamental beam generated by a seed laser is amplified by a fiber amplifier and partially converted to a second-harmonic beam by a second-harmonic generator. The residual fundamental beam and second-harmonic beam are separated, attenuated, and selectively coupled into the cores of the output optical fiber.
Claims20
A fiber laser, comprising:
- a seed laser providing a laser beam having a fundamental wavelength;
- a fiber amplifier arranged to receive and amplify the fundamental beam, the amplified fundamental beam being linearly polarized;
- a harmonic generator arranged to receive the amplified fundamental beam and partially convert the amplified fundamental beam into a laser beam having a harmonic wavelength corresponding to a harmonic of the fundamental wavelength, the partial conversion leaving a residual laser beam having the fundamental wavelength;
- a dichroic mirror arranged to intercept and spatially separate the residual fundamental beam and the harmonic beam;
- a first polarization modulator and a first polarizer arranged to receive the residual fundamental beam and to regulate power by passing at least portion thereof;
- a second polarization modulator and a second polarizer arranged to receive the harmonic beam and to regulate power by passing at least a portion thereof;
- an output optical fiber having a center core and an annular core;
- and
- a fiber combiner arranged to receive the regulated fundamental beam and the regulated harmonic beam, the fiber combiner configured to couple at least a portion of the regulated fundamental beam into a first one of the cores of the output optical fiber and to couple at least a portion of the regulated harmonic beam into a second one of the cores of the output optical fiber.
A method of laser processing a workpiece by applying laser radiation delivered through an output optical fiber, the output optical fiber having a center core and an annular core, comprising the steps of:
- generating a fundamental beam having a fundamental wavelength;
- amplifying the fundamental beam, the amplified fundamental beam being linearly polarized;
- converting a portion of the amplified fundamental beam into a harmonic beam having a wavelength corresponding to a harmonic of the fundamental wavelength, leaving a residual laser beam having the fundamental wavelength;
- separating the residual fundamental beam and the harmonic beam;
- coupling the residual fundamental beam into one of the cores of the output optical fiber;
- coupling the harmonic beam into the other core of the output optical fiber;
- and
- regulating the power of the residual fundamental beam coupled into the output optical fiber and independently regulating the power of the harmonic beam coupled into the output optical fiber;
- wherein the power of each beam is regulated by propagating the beam through a polarization modulator followed by a polarizer.
Dependencies are inferred from the claim text.