Abstract: A fiber laser amplifier system including a beam splitter that splits a feedback beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier for amplifying the fiber beam. A tapered fiber bundle couples the output ends of all of the fiber amplifiers into a combined fiber providing a combined output beam. A beam sampler samples a portion of the output beam from the tapered fiber bundle and provides a sample beam. A single mode fiber receives the sample beam from the beam sampler and provides the feedback beam.

Abstract: A fiber laser amplifier system including a plurality of master oscillators each generating a signal beam at a different wavelength. A splitter for each master oscillator splits the signal beam into a plurality of fiber beams to be separately amplified. A separate tapered fiber bundle receives the amplified beam for each master oscillator, where each tapered fiber bundle includes a plurality of input end fibers, a plurality of output end fibers and a center bundle portion, where each input end fiber is coupled to a separate one of the fiber amplifiers, where the bundle portion combines all of the fiber beams received by the input end fibers into a single combined beam and each output end fiber is capable of receiving the combined beam separately from the other output end fibers. A separate optical output channel receives one of the output end fibers from each tapered fiber bundle.

Abstract: A fiber laser amplifier system including a beam splitter that splits a feedback beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier for amplifying the fiber beam. A tapered fiber bundle couples all of the output ends of all of the fiber amplifiers into a combined fiber providing a combined output beam. An end cap is optically coupled to an output end of the tapered fiber bundle to expand the output beam. A beam sampler samples a portion of the output beam from the end cap and provides a sample beam. A single mode fiber receives the sample beam from the beam sampler and provides the feedback beam.

Abstract: An optical system including a plurality of fibers each providing a fiber beam and at least one tapered fiber bundle. The tapered fiber bundle includes a plurality of input end fibers, a plurality of output end fibers and a center bundle portion, where each input end fiber is coupled to a separate one of the fibers, and where the bundle portion combines all of the fiber beams received by the input end fibers into a single combined beam and each output end fiber is capable of receiving the combined beam separately from the other output end fibers. The optical system also includes a plurality of optical output channels where each optical output channel is coupled to a separate one of the output end fibers.

Abstract: A fiber laser amplifier system including a plurality of master oscillators each generating a signal beam at a different wavelength. A splitter for each master oscillator splits the signal beam into a plurality of fiber beams to be separately amplified. A separate tapered fiber bundle receives the amplified beam for each master oscillator, where each tapered fiber bundle includes a plurality of input end fibers, a plurality of output end fibers and a center bundle portion, where each input end fiber is coupled to a separate one of the fiber amplifiers, where the bundle portion combines all of the fiber beams received by the input end fibers into a single combined beam and each output end fiber is capable of receiving the combined beam separately from the other output end fibers. A separate optical output channel receives one of the output end fibers from each tapered fiber bundle.

Abstract: An optical system including a plurality of fibers each providing a fiber beam and at least one tapered fiber bundle. The tapered fiber bundle includes a plurality of input end fibers, a plurality of output end fibers and a center bundle portion, where each input end fiber is coupled to a separate one of the fibers, and where the bundle portion combines all of the fiber beams received by the input end fibers into a single combined beam and each output end fiber is capable of receiving the combined beam separately from the other output end fibers. The optical system also includes a plurality of optical output channels where each optical output channel is coupled to a separate one of the output end fibers.

Abstract: A fiber laser amplifier system including a plurality of master oscillators each generating a signal beam at a different wavelength. A splitter is provided for each master oscillator that splits the signal beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier. A tapered fiber bundle couples the output ends the fiber amplifiers for each wavelength group into a combined fiber providing a combined output beam, where a separate combined output beam is provided for the wavelength for each master oscillator. An end cap is optically coupled to an output end of each of the tapered fiber bundles to expand the combined output beam. A spectral beam combination grating receives the combined beams from the tapered fiber bundles at different angles and outputs an output beam of all of the combined beams as a single beam being directed in the same direction.

Abstract: A fiber laser amplifier system including a master oscillator that generates a signal beam. A splitter splits the signal beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier for amplifying the fiber beam. A tapered fiber bundle couples all of the output ends of all of the fiber amplifiers into a combined fiber providing a combined output beam. An end cap is optically coupled to an output end of the tapered fiber bundle to expand the output beam.

Abstract: A fiber laser amplifier system including a plurality of master oscillators each generating a signal beam at a different wavelength. A splitter is provided for each master oscillator that splits the signal beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier. A tapered fiber bundle couples the output ends the fiber amplifiers for each wavelength group into a combined fiber providing a combined output beam, where a separate combined output beam is provided for the wavelength for each master oscillator. An end cap is optically coupled to an output end of each of the tapered fiber bundles to expand the combined output beam. A spectral beam combination grating receives the combined beams from the tapered fiber bundles at different angles and outputs an output beam of all of the combined beams as a single beam being directed in the same direction.

Abstract: A fiber laser amplifier system including a master oscillator that generates a signal beam. A splitter splits the signal beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier for amplifying the fiber beam. A tapered fiber bundle couples all of the output ends of all of the fiber amplifiers into a combined fiber providing a combined output beam. An end cap is optically coupled to an output end of the tapered fiber bundle to expand the output beam.

Abstract: A fiber laser amplifier system including a beam splitter that splits a feedback beam into a plurality of fiber beams where a separate fiber beam is sent to a fiber amplifier for amplifying the fiber beam. A tapered fiber bundle couples all of the output ends of all of the fiber amplifiers into a combined fiber providing a combined output beam. An end cap is optically coupled to an output end of the tapered fiber bundle to expand the output beam. A beam sampler samples a portion of the output beam from the end cap and provides a sample beam. A single mode fiber receives the sample beam from the beam sampler and provides the feedback beam.

Abstract: A transmissive or reflective diffractive optical element, comprising: a substrate having a top surface, the top surface being etched into a pattern, the pattern including a periodic surface pattern of grooves formed such that when an incoming light beam is shone onto the top surface, the incoming light beam will be split into a plurality of diffracted light beams, the plurality of diffracted light beams including a plurality of primary diffracted order beams and a plurality of secondary diffracted order beams, wherein the primary diffracted order beams have a primary aggregate efficiency above ninety percent, wherein the plurality of secondary diffracted order beams have a secondary aggregate efficiency of lower than ten percent, and wherein a maximum power of the primary diffracted order beams and a minimum power of the primary diffracted order beams differ by at least ten percent of an average power of the primary diffracted order beams.

Abstract: A transmissive or reflective diffractive optical element, comprising: a substrate having a top surface, the top surface being etched into a pattern, the pattern including a periodic surface pattern of grooves formed such that when an incoming light beam is shone onto the top surface, the incoming light beam will be split into a plurality of diffracted light beams, the plurality of diffracted light beams including a plurality of primary diffracted order beams and a plurality of secondary diffracted order beams, wherein the primary diffracted order beams have a primary aggregate efficiency above ninety percent, wherein the plurality of secondary diffracted order beams have a secondary aggregate efficiency of lower than ten percent, and wherein a maximum power of the primary diffracted order beams and a minimum power of the primary diffracted order beams differ by at least ten percent of an average power of the primary diffracted order beams.

Abstract: A fiber laser system and a related method for its use, in which one or more fiber laser amplifiers are cryogenically cooled and optimized to operate at a desirably high efficiency. Versions of the laser system using either thulium or erbium doped fibers are disclosed. In a high power version of the system, the outputs of multiple fiber lasers are coherently combined. Cooling by a selected liquefied gas, such as nitrogen, is applied to the fiber laser amplifiers and, optionally, to pump diodes and to optical elements used to combine the outputs of the fiber laser amplifiers.

Abstract: An optical beam combiner and a related method for its operation, in which multiple coherent input beams are directed onto a diffractive optical element (DOE) along directions corresponding to diffraction orders of the DOE, such that the DOE generates a single output beam in a direction corresponding to a desired diffraction order, and suppresses outputs in directions corresponding to unwanted diffraction orders. The phases of the input beams are actively controlled to ensure and maintain the condition that only a single diffraction mode is present in the output of the DOE.