Fiber laser based production of laser drilled microvias for multi-layer drilling, dicing, trimming or milling applications

A method for laser machining a target workpiece, comprising the steps of:

• generating and directing at least one pulse stack into a selected region of the target workpiece, including the steps of
• generating a plurality of sequences of laser beam pulses from a fiber laser wherein the pulses of each sequence of pulses are separated by a corresponding repetition interval, and
• combining the plurality of sequences of laser beam pulses into at least one pulse stack output that includes a laser beam pulse from each sequence of laser beam pulses wherein an inter-stack interval between sequential pulse stacks and an inter-pulse interval between the pulses of each pulse stack is determined by an initial firing time and a repetition rate of the pulses of each sequence of pulses, and
• focusing and directing the at least one pulse stack output into the selected region of the target workpiece.

A method for laser machining a target workpiece, comprising the steps of:

• generating an output laser beam including a sequence of at least one of a continuous wave output component, a pseudo-continuous wave output component and a pulse sequence output component into a selected region of the target workpiece, including the steps of
• generating a sequence of output components in each of a plurality of component fiber lasers, and
• combining the sequence of output components from each of the plurality of component fiber lasers into a single fiber laser output beam, and
• focusing and directing the single fiber laser output beam into the selected region of the target workpiece.

A multi-pumped fiber laser, comprising:

• an optical fiber,
• a first end structure, including
• a first optical path including a first beam splitter for coupling an output of a first pump laser to the first end of the optical fiber to drive the optical fiber, and
• a second optical path including the first beam splitter for coupling the first end of the optical fiber to an optical reflecting element assembly to form a first reflecting end of the resonant optical cavity,
• a second end structure, including
• a third optical path including a second beam splitter for coupling an output of a second pump laser to a second end of the optical fiber to drive the optical fiber, and
• a fourth optical path including the second beam splitter for coupling the second end of the optical fiber to a second optical reflecting element assembly to form a second reflecting end of the resonant optical cavity, and
• an output path, including
• a third beam splitter located in the fourth optical path for coupling an output from the second end of the optical fiber passing through the fourth optical path to a beam output of the fiber laser.

A fiber laser for generating laser beam pulse stacks, comprising:

• an optical fiber,
• a first end structure, including
• a first optical path for coupling an output of a first pump laser to the first end of the optical fiber to drive the optical fiber, and
• a second optical path forming a first reflecting end of the resonant optical cavity,
• a second end structure, including
• a third optical path for coupling an output of a second pump laser to a second end of the optical fiber to drive the optical fiber, and
• a fourth optical path forming a second reflecting end of the resonant optical cavity, and
• an output path for directing a beam output of the optic fiber to a beam output of the fiber laser, wherein
• the first and second pump lasers are synchronized to generate a plurality of sequences of laser beam pulses from the optic fiber wherein
• the pulses of each sequence of pulses are separated by a corresponding repetition interval, and
• the plurality of sequences of laser beam pulses form at least one pulse stack output that includes a laser beam pulse from each sequence of laser beam pulses wherein an inter-stack interval between sequential pulse stacks and an inter-pulse interval between the pulses of each pulse stack is determined by an initial firing time and a repetition rate of the pulses of each sequence of pulses.

A fiber laser for generating laser beam pulse stacks, comprising:

• a plurality of component fiber lasers for generating individual sequences of output pulses, and
• an optical structure for combining the of each of the plurality of component fiber lasers into a single fiber laser output, wherein
• the sequences of output pulses from at least certain selected component fiber lasers are synchronized in time so that
• the pulses of each sequence of pulses are separated by a corresponding repetition interval, and wherein
• an inter-stack interval between sequential pulse stacks and an inter-pulse interval between the pulses of each pulse stack is determined by an initial firing time and a repetition rate of the pulses of each sequence of pulses.

A laser for generating an output laser beam including a sequence of at least one of a continuous wave output component, a pseudo-continuous wave output component and a pulse sequence output component, comprising:

• a plurality of component fiber lasers,
• each component fiber laser generating an output component including at least one of a continuous wave output component, a pseudo-continuous wave output component and a pulse sequence output component, and
• an optical structure for combining the output components of each of the plurality of component fiber lasers into a single fiber laser output, wherein
• the output components generated by at least selected ones of the plurality of component fiber lasers are synchronized in time so that the single fiber laser output includes a sequence of at least one of a continuous wave output component, a pseudo-continuous wave output component and a pulse sequence output component.