Patents by Inventor Steven J. Augst
Steven J. Augst has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20210349281Abstract: High-power light absorbers (HPLAs) can exhibit low back-scattered light, mitigate stray light, and withstand high optical power. The absorbers can be used with or without baffling as beam dumps for high-power lasers. An HPLA may include a substrate made of high thermally conductive material with an anti-reflection (AR) coating formed on the substrate. A thin layer of highly absorbing material may be located between the AR coating and substrate. The substrate can be cooled with a fluid, such as water or air.Type: ApplicationFiled: December 22, 2020Publication date: November 11, 2021Inventors: Steven J. AUGST, Peter O'Brien, Jonathan Wilson
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Patent number: 11108209Abstract: Stimulated Brillouin scattering (SBS) limits the maximum power in fiber lasers with narrow linewidths. SBS occurs when the power exceeds a threshold proportional to the beam area divided by the effective fiber length. The fiber lasers disclosed here operate with higher SBS power thresholds (and hence higher maximum powers at kilohertz-class linewidths) than other fiber lasers thanks to several techniques. These techniques include using high-absorption gain fibers, operating the laser with low pump absorption (e.g., ?80%), reducing the length of un-pumped gain fiber at the fiber output, foregoing a delivery fiber at the output, foregoing a cladding light stripper at the output, using free-space dichroic mirrors to separate signal light from unabsorbed pump light, and using cascaded gain fibers with non-overlapping Stokes shifts. The upstream gain fiber has high absorption and a larger diameter for high gain, and subsequent gain fiber has a smaller diameter to improve beam quality.Type: GrantFiled: May 1, 2020Date of Patent: August 31, 2021Assignee: Massachusetts Institute of TechnologyInventors: Steven J. Augst, Kelsey Yee, Franklin Jose
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Publication number: 20210006029Abstract: Stimulated Brillouin scattering (SBS) limits the maximum power in fiber lasers with narrow linewidths. SBS occurs when the power exceeds a threshold proportional to the beam area divided by the effective fiber length. The fiber lasers disclosed here operate with higher SBS power thresholds (and hence higher maximum powers at kilohertz-class linewidths) than other fiber lasers thanks to several techniques. These techniques include using high-absorption gain fibers, operating the laser with low pump absorption (e.g., ?80%), reducing the length of un-pumped gain fiber at the fiber output, foregoing a delivery fiber at the output, foregoing a cladding light stripper at the output, using free-space dichroic mirrors to separate signal light from unabsorbed pump light, and using cascaded gain fibers with non-overlapping Stokes shifts. The upstream gain fiber has high absorption and a larger diameter for high gain, and subsequent gain fiber has a smaller diameter to improve beam quality.Type: ApplicationFiled: May 1, 2020Publication date: January 7, 2021Inventors: Steven J. AUGST, Kelsey Yee, Franklin Jose
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Patent number: 10374379Abstract: A fiber amplifier includes an isolator, a gain fiber to amplify an input laser signal, and an optical filter disposed between the isolator and the gain fiber. The optical filter transmits the laser signal and reflects amplified spontaneous emission (ASE) propagating from the gain fiber toward the isolator. The reflected ASE reenters the gain fiber and is absorbed by the gain fiber for amplifying the input laser signal. The optical filter in the amplifier can protect the usually expensive isolator and reduce potential damage to the gain fiber induced by fluctuation of the input laser signal power, as well as reduce potential photodarkening at the input of the gain fiber.Type: GrantFiled: September 9, 2016Date of Patent: August 6, 2019Assignee: Massachusetts Institute of TechnologyInventor: Steven J. Augst
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Publication number: 20180261969Abstract: A fiber amplifier includes an isolator, a gain fiber to amplify an input laser signal, and an optical filter disposed between the isolator and the gain fiber. The optical filter transmits the laser signal and reflects amplified spontaneous emission (ASE) propagating from the gain fiber toward the isolator. The reflected ASE reenters the gain fiber and is absorbed by the gain fiber for amplifying the input laser signal. The optical filter in the amplifier can protect the usually expensive isolator and reduce potential damage to the gain fiber induced by fluctuation of the input laser signal power, as well as reduce potential photodarkening at the input of the gain fiber.Type: ApplicationFiled: September 9, 2016Publication date: September 13, 2018Inventor: Steven J. Augst
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Patent number: 9136667Abstract: A method and apparatus for providing a high peak power optical beam. The method includes interleaving pulse trains of different wavelengths and spatially and temporally overlapping the different wavelengths to produce an amplified output beam with very high peak power.Type: GrantFiled: August 22, 2013Date of Patent: September 15, 2015Assignee: MASSACHUSETTS INSTITUTE OF TECHNOLOGYInventors: Bien Chann, Tso Yee Fan, Antonio Sanchez-Rubio, Steven J. Augst
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Patent number: 9134538Abstract: Coherent beam combining of laser gain elements achieves high output power in a diffraction limited beam. An active beam combining system coherently combines optical beams emitted by semiconductor laser gain elements in an external resonant cavity configuration. A beam combiner in the resonant cavity combines the outputs of the laser gain elements into a single coherent output beam whose power is monitored by a photodetector. A processor uses the photodetector's output to adjust the phases of the respective optical beams emitted by the laser gain elements so as to increase or maximize the coherent output beam's power. The processor may vary the optical beams' phases according to a stochastic parallel gradient descent (SPGD) algorithm for active phase control. Experimental results show a beam combining efficiency of 81% with an upper limit of 90% or higher and without the scaling limits imposed on passive-phasing systems.Type: GrantFiled: February 6, 2013Date of Patent: September 15, 2015Assignee: Massachusetts Institute of TechnologyInventors: Steven J. Augst, Juan Camilo Montoya, Tso Yee Fan, Antonio Sanchez-Rubio
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Publication number: 20130342895Abstract: A method and apparatus for providing a high peak power optical beam. The method includes interleaving pulse trains of different wavelengths and spatially and temporally overlapping the different wavelengths to produce an amplified output beam with very high peak power.Type: ApplicationFiled: August 22, 2013Publication date: December 26, 2013Applicant: MASSACHUSETTS INSTITUTE OF TECHNOLOGYInventors: Bien Chann, Tso Yee Fan, Antonio Sanchez-Rubio, Steven J. Augst
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Patent number: 8531761Abstract: A method and apparatus for providing a high peak power optical beam. The method includes interleaving pulse trains of different wavelengths and spatially and temporally overlapping the different wavelengths to produce an amplified output beam with very high peak power.Type: GrantFiled: May 27, 2010Date of Patent: September 10, 2013Assignee: Massachusetts Institute of TechnologyInventors: Bien Chann, Tso Yee Fan, Antonio Sanchez-Rubio, Steven J. Augst
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Publication number: 20110292498Abstract: A method and apparatus for providing a high peak power optical beam. The method includes interleaving pulse trains of different wavelengths and spatially and temporally overlapping the different wavelengths to produce an amplified output beam with very high peak power.Type: ApplicationFiled: May 27, 2010Publication date: December 1, 2011Applicant: Massachusetts Institute of TechnologyInventors: Bien Chann, Tso Yee Fan, Antonio Sanchez-Rubio, Steven J. Augst
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Publication number: 20110280581Abstract: A method of operating a high-output-power fiber laser system includes: time multiplexing a plurality of pulses, each pulse having a pulse width, and each having a different wavelength from a plurality of seed oscillators onto a single fiber; setting each pulse width to a width less than the phonon lifetime; separating in time each pulse from each other pulse so as to leave a gap between adjacent pulses; setting a time between pulses each having a common wavelength to a time longer than a round-trip time of flight through a fiber amplifier of pulses having the common wavelength; and injecting the plurality of pulses from the single fiber into the fiber amplifier. Also to disclosed is a system capable of performing the method.Type: ApplicationFiled: May 12, 2010Publication date: November 17, 2011Applicant: MASSACHUSETTS INSTITUTE OF TECHNOLOGYInventors: Bien Chann, Steven J. Augst, Tso Yee Fan, Antonio Sanchez-Rubio