DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
Claims 1-11 and 13-21 are currently pending.
Applicant’s amendment, filed 07 April 2026, overcomes the prior rejection(s). However, the amendment introduces a new ground(s) of rejection.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1, 5-6, 8-9, 13-14 and 17-19 are rejected under 35 U.S.C. 102(a)(1) and 102(a)(2) as being anticipated by Mourou (US20090219610A1).
Regarding claim 1, Mourou discloses an optical system (Fig. 3, optical pulse amplifier 31, as further detailed in Fig. 5, optical pulse amplifier 51; ¶¶ 2, 31-32), comprising:
a dividing element, arranged to divide an input laser beam into a number of spatially separate sub-beams (Fig. 5, splitter 54a; ¶¶ 33-34);
at least one optical amplifier, through which the spatially separate sub-beams propagate (Fig. 5, fiber amplifiers 52d and LMA fiber amplifiers 57 of separate branches; ¶¶ 34-35),
at least one path-length adjustment element, which is arranged to adjust the path length of at least one of the sub-beams (Fig. 5, optical length/phase modulators at the input of stage IV; ¶ 48, path-delay control “can be accomplished by using fiber stretching (through piezoelectric modulators, for example) in each optical branch”; ¶ 49, feedback controls the “optical-path modulator” to match optical path lengths);
a combination element, arranged to coherently superimpose the sub-beams in an output laser beam (Fig. 3, fiber bundle 36 and pupil 37 producing amplified pulse 38; ¶ 46, coherently combine all optical-branch outputs into a single coherent beam), the combination element arranged shortly before a beam outlet opening of the system or at a location of an application (Fig. 3, output fiber bundle 36/pupil 37; Figs. 6A-6C, final fiber array/pupil; ¶ 41, last-stage fibers are “organized in an fiber array to form a pupil configuration” and the “pupil is used to focus the output signals to a target”; ¶ 47, “fiber-array output aperture”); and
at least one optical functional element from the group of a spectral broadening element, an optical modulator and a pulse compressor, wherein the at least one optical functional element is arranged after the at least one optical amplifier in the beam path, through which the spatially separate sub-beams propagate (Fig. 3, pulse compressor 35 after fiber network 33/transport fibers 34; ¶ 31; Fig. 5, pulse compressor(s) 59 in stage SV after branch amplifiers 52d/57; ¶¶ 35, 44).
Regarding claim 5, Mourou discloses the optical system of claim 1, and further discloses: wherein the sub-beams form a two-dimensional array in a plane transverse to the propagation direction (Fig. 3, fiber bundle 36/pupil 37; ¶ 30, “fiber bundle transverse distribution”; ¶ 31, “fiber bundle…associated to a pupil 37 to form a fiber array”; Figs. 6A-6C; ¶ 41, last-stage fibers “organized in an fiber array to form a pupil configuration”).
Regarding claim 6, Mourou discloses the optical system of claim 1, and further discloses: wherein provision is made for an error signal detector, which is arranged to derive an error signal from the output laser beam or from the sub-beams, and a controller, which is arranged to derive from the error signal at least one control signal to control the at least one path-length adjustment element (¶ 47, “fiber array output is sampled with a beam-splitter and then imaged into a photo-detector array,” producing a beat/phase signal used to control phase modulators; ¶ 49, beat frequency is converted into an “electronic feedback signal” to “control the optical-path modulator” and match path lengths).
Regarding claim 8, Mourou discloses the optical system of claim 1, and further discloses: wherein the at least one path-length adjustment element is arranged ahead of the at least one optical amplifier in the beam path (Fig. 5, stage IV branch including splitter 53c followed by Pockel cell 55/fiber amplifier 52d; ¶¶ 34, 48, optical length/phase modulators “could be at the input of each fiber in the IV-th stage”).
Regarding claim 9, Mourou discloses the optical system of claim 1, and further discloses: wherein the combination element is located at a location of an application of the output laser beam (¶ 44, “Coherent beam combining would need to be accomplished after pulse recompression (in the far-field)”; Figs. 6A-6C; ¶ 41, “used to focus the output signals to a target”).
Regarding claim 13, Mourou discloses the optical system of claim 1, and further discloses: wherein the at least one path-length adjustment element is located between the dividing element and the at least one optical amplifier (Fig. 5, splitter 53c feeding stage IV branch before fiber amplifier 52d; ¶¶ 34, 48, optical length/phase modulators may be located “at the input of each fiber in the IV-th stage”).
Regarding claim 14, Mourou discloses an optical system (Fig. 3, optical pulse amplifier 31, as further detailed in Fig. 5, optical pulse amplifier 51), comprising:
a dividing element, arranged to divide an input laser beam into a number of spatially separate sub-beams (Fig. 5, splitter 54a; ¶¶ 33-34);
at least one single-pass optical amplifier, through which the spatially separate sub-beams propagate (Fig. 5, optical fiber amplifiers 51b, 52d and LMA fiber amplifiers 57; ¶ 7, “a plurality of optical fiber amplifiers, each optical fiber amplifier being connected to one of said plurality of outputs”; ¶¶ 33-35, each branch includes fiber amplifiers, where the fiber amplifiers are further characterized in Fig. 7, fiber amplifier 71/Yb-fiber 74; ¶ 39, input pulse 73 is pumped into Yb-fiber 74, and where single-pass is supported by the disclosed linear fiber amplifier path);
at least one path-length adjustment element, which is arranged to adjust the path length of at least one of the sub-beams (Fig. 5, optical length/phase modulators at the input of stage IV; ¶ 48, path-delay control “can be accomplished by using fiber stretching (through piezoelectric modulators, for example) in each optical branch”; ¶ 49, feedback controls the “optical-path modulator” to match optical path lengths);
a combination element, arranged to coherently superimpose the sub-beams in an output laser beam (Fig. 3, fiber bundle 36 and pupil 37 producing amplified pulse 38; ¶ 46, coherently combine all optical-branch outputs into a single coherent beam), the combination element arranged shortly before a beam outlet opening of the system or at a location of an application (Fig. 3, output fiber bundle 36/pupil 37; Figs. 6A-6C, final fiber array/pupil; ¶ 41, last-stage fibers are “organized in an fiber array to form a pupil configuration” and the “pupil is used to focus the output signals to a target”; ¶ 47, “fiber-array output aperture”); and
at least one optical functional element from the group of a spectral broadening element, an optical modulator, an optical isolator and a pulse compressor, wherein the at least one optical functional element is arranged after the at least one optical amplifier in the beam path, through which the spatially separate sub-beams propagate (Fig. 3, pulse compressor 35 after fiber network 33/transport fibers 34; ¶ 31; Fig. 5, pulse compressor(s) 59 in stage SV after branch amplifiers 52d/57; ¶¶ 35, 44).
Regarding claim 17, Mourou discloses the optical system of claim 14, and further discloses: wherein the sub-beams form a two- dimensional array in a plane transverse to the propagation direction (Figs. 6A-6C, fiber bundle cross sections with fibers distributed in two transverse dimension).
Regarding claim 18, Mourou discloses an optical system (Fig. 3, optical pulse amplifier 31, as further detailed in Fig. 5, optical pulse amplifier 51), comprising:
a dividing element, arranged to divide an input laser beam into a number of spatially separate sub-beams (Fig. 5, splitter 54a; ¶¶ 33-34);
at least one optical amplifier, through which the spatially separate sub-beams propagate (Fig. 5, optical fiber amplifiers 51b, 52d, LMA fiber amplifier 57; ¶¶ 33-35);
a path-length adjustment element arranged in series between the dividing element and the optical amplifier to adjust the path length of at least one of the sub-beams (Fig. 5, stage-IV branch inputs before fiber amplifier 52d / stage-IV fibers; ¶ 48, “control absolute time delays between each of the optical paths… using fiber stretching (through piezoelectric modulators, for example) in each optical branch”; ¶ 48, “Location of these optical-length/optical-phase modulators could be at the input of each fiber in the IV-th stage of the system”; ¶ 48, feedback applied to “fiber-length and phase modulators” to correct “length and phase mismatch”);
a combination element, arranged to coherently superimpose the sub-beams in an output laser beam (Fig. 3, fiber bundle 36 and pupil 37 producing amplified pulse 38; ¶ 46, coherently combine all optical-branch outputs into a single coherent beam), the combination element arranged shortly before a beam outlet opening of the system or at a location of an application (Fig. 3, output fiber bundle 36/pupil 37; Figs. 6A-6C, final fiber array/pupil; ¶ 41, last-stage fibers are “organized in an fiber array to form a pupil configuration” and the “pupil is used to focus the output signals to a target”; ¶ 47, “fiber-array output aperture”); and
an optical functional element from the group of a spectral broadening element, an optical isolator, an optical modulator and a pulse compressor, wherein the optical functional element is arranged after the at least one optical amplifier in the beam path, through which the spatially separate sub-beams propagate (Fig. 3, pulse compressor 35 after fiber network 33/transport fibers 34; ¶ 31; Fig. 5, pulse compressor(s) 59 in stage SV after branch amplifiers 52d/57; ¶¶ 35, 44).
Regarding claim 19, Mourou discloses the optical system of claim 18, and further discloses: comprising a controller (¶ 47, “proper electronic circuitry”; ¶ 48, feedback applied to “fiber-length and phase modulators”; ¶ 49, “Feedback control loop” controls optical path modulators), wherein provision is made for an error signal detector that is arranged to derive an error signal from the output laser beam or from the sub-beams (Fig. 3, fiber-array output from fiber bundle 36 / pupil 37; ¶ 47, “small fraction of fiber array output is sampled with a beam-splitter and then imaged into a photo-detector array”; ¶ 49, “measuring a beat frequency from each individual detector one could determine optical path difference”), and the controller is arranged to derive from the error signal at least one control signal to control the at least one path-length adjustment element (¶ 48, feedback signal applied to “each fiber-length and phase modulators” to correct “length and phase mismatch”; ¶ 49).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Mourou in view of Rothenberg (US20080084598A1).
Regarding claim 2, Mourou discloses the optical system of claim 1, however does not discloses: wherein the dividing element and/or the combination element are each formed as diffractive beam splitters. Rothenberg teaches the limitation, specifically: a diffractive optical element configured to split one beam into multiple diffracted beams (Fig. 4, DOE phase pattern 43; Fig. 5, five diffracted orders; ¶ 36, “DOEs can be designed to efficiently combine or split an arbitrarily large number of beams, in 1D or 2D arrays,” and a single incident beam is split among “five diffracted orders”); and a diffractive optical element configured, in reverse, to combine plural beams into one coherent output beam (Fig. 1, DOE 25 combining collimated beams 24 into output beam 27; ¶¶ 26, 38, “Coherent diffractive beam combining is achieved by using the DOE ‘in reverse’”; ¶ 11, “The DOE operates as a beam combiner to allow efficient coherent combination of the beams at a desired diffraction order”). It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the splitter and/or coherent combining arrangement of Mourou with the diffractive optical element beam splitter/combiner of Klenke, because doing so would predictably improve beam combination efficiency, reduce optical element count, and minimize distortion/thermal issues in high power beam combining (Rothenberg, ¶¶ 28, 35, 43).
Claims 3-4 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Mourou in view of Klenke (US20170179666A1).
Regarding claim 3, Mourou discloses the optical system of claim 1, however does not discloses: wherein the dividing element and/or the combination element are each formed as a reflective element with zones of different reflectivity. Klenke teaches a dividing/splitting element formed by a partially reflective element having different-reflectivity zones (Fig. 1, splitting element 1, partially reflective element 2, zones a-d; ¶ 48, “partially reflective element 2 consists of N…zones a, b, c, d having different reflectivity”), and a corresponding combining element formed the same way (Figs. 2-4, combining element 4; ¶ 49, “combining element 4…has the same construction as partially reflective element 2′ and reflective element 3′” and “superposes the partial beams T1 to TN in one output beam A”). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the splitter/combiner architecture of Mourou with the reflective-zone splitting and combining elements of Klenke with a reasonable expectation of success, because doing so would predictably provide scalable, compact, and dispersion-controlled beam division and recombination.
Regarding claim 4, Mourou in view of Klenke teaches the optical system of claim 3, and further teaches: wherein the dividing element and/or the combination element each comprise two or more reflective elements at which the laser radiation is reflected consecutively one or multiple times (Klenke, Fig. 1, partially reflective element 2 and reflective element 3; ¶ 48, “input beam E is reflected to and fro multiple times between the partially reflective element 2 and the plane-parallel reflective element 3”; Figs. 2-4, combining element 4 with elements 2′/3′; ¶ 49).
Regarding claim 7, Mourou discloses the optical system of claim 1, however does not discloses: wherein the at least one optical amplifier is an optically pumped multicore waveguide, which is doped with rare earth ions and in which a plurality of waveguide structures is integrated, wherein each waveguide structure is arranged to carry one of the sub-beams. Klenke teaches the limitation, specifically: an optically pumped doped multicore fiber amplifier in which partial beams are amplified in respective cores (Fig. 3, monolithic multichannel element MV; ¶ 51, MV can be “a multicore fiber”; ¶ 39, “partial beams are then amplified in the cores of an optically pumped multicore fiber, which is doped with, for example, erbium or ytterbium”; ¶ 41, “an optically pumped, doped multicore fiber…having a plurality of signal cores can be used…wherein the laser pulses are split and recombined”), and further teaches that multiple optical elements may be integrated into a single monolithic multichannel element through which the partial beams propagate spatially separately (¶ 26). It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the plurality of separate fiber amplifier branches of Mourou with the optically pumped rare-earth-doped multicore waveguide amplifier of Klenke, because doing so would predictably reduce complexity and alignment burden, improve compactness and stability, and enable scalable parallel amplification within a single integrated structure.
Claims 10 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Mourou in view of Ciu (“Spectral phase effects and control requirements of coherent beam combining for ultrashort ultrahigh intensity laser systems,” published 2016)1.
Regarding claim 10, Mourou discloses the optical system of claim 1, however does not disclose: wherein the pulse compressor is an arrangement of one or more grating pairs or prism pairs, wherein each grating or prism pair is penetrated by each of the spatially separate sub-beams single or multiple times. Ciu teaches the limitation in Fig. 2 in which each channel includes a pulse compressor (§2, p. 10126, “compression in every channel”); each compressor implemented as a grating pair or prism pair (§3.C, p. 10129, “grating double, prism double”). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the pulse compressor of Mourou with the teachings of Ciu with the motivation to preventing pulse broadening and peak-power loss (Ciu, §2, p. 10126), thereby yielding a system with greater pulse control and improved beam quality/precision.
Regarding claim 20, Mourou discloses the optical system of claim 1, however does not disclose: wherein the optical functional element is a pulse compressor formed as an arrangement of one or more grating pairs or prism pairs, and wherein each grating or prism pair is penetrated by each of the spatially separate sub- beams single or multiple times. Ciu teaches the limitation in Fig. 2 in which each channel includes a pulse compressor (§2, p. 10126, “compression in every channel”); each compressor implemented as a grating pair or prism pair (§3.C, p. 10129, “grating double, prism double”). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the pulse compressor of Mourou with the teachings of Ciu with the motivation to preventing pulse broadening and peak-power loss (Ciu, §2, p. 10126), thereby yielding a system with greater pulse control and improved beam quality/precision.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Mourou in view of Wilcox (US20180031851A1).
Regarding claim 15, Mourou discloses the optical system of claim 14, however does not discloses: wherein one or more of the dividing element and the combination element is formed as a diffractive beam splitter. Wilcox teaches the limitation in Fig. 2, DOE2 & Fig. 3, 315; ¶¶ 31-32, 38. It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the optical system of Mourou with the teachings of Wilcox with a reasonable expectation of success because Wilcox teaches that diffractive optical elements can split or combine beams with high efficiency while compensating angular dispersion, thereby reducing or eliminating pulse-front tilt and angular-dispersion penalties while maintaining efficient beam handling (Wilcox, Fig. 2; ¶¶ 30-31, 39).
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Mourou in view of KlenkeNPL (“Coherently combined 16-channel multicore fiber laser system,” published 2018)2.
Regarding claim 16, Mourou discloses the optical system of claim 14, however does not discloses: wherein one or more of the dividing element and the combination element is formed as a reflective element with zones of different reflectivity. KlenkeNPL teaches the limitation in Fig. 1, beam splitter SMS 1/SMS 2 and beam combiner SMS 1/SMS 2; p. 1520, SMS made from a high-reflective mirror and an element with 0%, 50%, 66%, and 75% reflectivity zones; p. 1520, post-amplification beam combination using another two SMS elements. It would have been obvious to a person of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the optical system of Mourou with the teachings of KlenkeNPL with a reasonable expectation of success in order to reduce the number of required optical components, improve scalability to a larger number of channels, preserve filled aperture coherent beam combination, and enhance average power handling.
Claims 1, 11, 18 and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Klenke in view of Rothhardt (“1 MHz repetition rate hollow fiber pulse compression to sub-100-fs duration at 100 W average power,” published 2011)3.
Regarding claim 1, Klenke discloses an optical system (Fig. 4, where element 1 is further detailed in Fig. 1), comprising:
a dividing element, arranged to divide an input laser beam into a number of spatially separate sub-beams (Fig. 1, splitting element 1, partially reflective element 2, reflective element 3; input beam E split into partial beams T1–TN; ¶¶ 35, 48);
at least one optical amplifier, through which the spatially separate sub-beams propagate (Fig. 4, multichannel element MV as “multicore fiber”; ¶ 51),
at least one path-length adjustment element, which is arranged to adjust the path length of at least one of the sub-beams (Fig. 4, P; ¶¶ 34, 52 “mechanically movable elements, such as… mirrors… or movable transmission wedges” for adjusting phase);
a combination element, arranged to coherently superimpose the sub-beams in an output laser beam (Fig. 4, combining element 4; ¶¶ 49, 52), the combination element arranged shortly before a beam outlet opening of the system or at a location of an application (Fig. 4, forming output beam A prior to exiting beam output opening of 4); and […].
Although the referenced embodiment of Klenke does not expressly teach: “at least one optical functional element from the group of a spectral broadening element, an optical modulator and a pulse compressor, wherein the at least one optical functional element is arranged after the at least one optical amplifier in the beam path, through which the spatially separate sub-beams propagate,” Klenke separately teaches using the same optical-array architecture for spectral broadening, where “the at least one optical element is an optical amplifier or a nonlinear optical element for spectral broadening” (¶ 23), and where the system is suitable for “spectral broadening of femtosecond pulses” in “a hollow-core fiber having a plurality of cores,” with spectral broadening occurring “separately in each core” (¶ 42). However, Klenke does not teach: “wherein the at least one optical functional element is arranged after the at least one optical amplifier in the beam path.” Rothhardt teaches that a high-power fiber chirped-pulse amplification system delivers the pulses, and that “subsequent spectral broadening in a xenon-filled hollow-core fiber and pulse compression with chirped mirrors” is used for pulse shortening and peak-power enhancement, i.e., expressly teaching subsequent broadening after the amplifier output.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the optical system of Klenke with the further teachings of Klenke and Rothhardt with a reasonable expectation for success in order to enable post-amplification spectral broadening at higher pulse energies by distributing the amplified beam among multiple cores, thereby keeping each broadening channel within its practical operating limits and increasing the spectral bandwidth of the system.
Regarding claim 11, Klenke in view of Rothhardt teaches the optical system of claim 1, and further teaches: wherein the spectral broadening element is a multicore waveguide in which a plurality of waveguide structures is integrated, wherein each waveguide structure carries one of the sub-beams (Klenke, ¶¶ 23, 42).
Regarding claim 18, Klenke discloses an optical system (Fig. 4, where element 1 is further detailed in Fig. 1), comprising:
a dividing element, arranged to divide an input laser beam into a number of spatially separate sub-beams (Fig. 1, splitting element 1, partially reflective element 2, reflective element 3; input beam E split into partial beams T1–TN; ¶¶ 35, 48);
at least one optical amplifier, through which the spatially separate sub-beams propagate (Fig. 4, multichannel element MV as “multicore fiber”; ¶ 51),
a path-length adjustment element arranged in series between the dividing element and the optical amplifier to adjust the path length of at least one of the sub-beams (Fig. 4, P; ¶¶ 34, 52 “mechanically movable elements, such as… mirrors… or movable transmission wedges” for adjusting phase; Fig. 4, P placed between splitting element 1 and amplifier MV; ¶ 34);
a combination element, arranged to coherently superimpose the sub-beams in an output laser beam (Fig. 4, combining element 4; ¶¶ 49, 52), the combination element arranged shortly before a beam outlet opening of the system or at a location of an application (Fig. 4, forming output beam A prior to exiting beam output opening of 4); and […].
Although the referenced embodiment of Klenke does not expressly teach: “an optical functional element from the group of a spectral broadening element, an optical isolator, an optical modulator and a pulse compressor, wherein the optical functional element is arranged after the at least one optical amplifier in the beam path, through which the spatially separate sub-beams propagate,” Klenke separately teaches using the same optical-array architecture for spectral broadening, where “the at least one optical element is an optical amplifier or a nonlinear optical element for spectral broadening” (¶ 23), and where the system is suitable for “spectral broadening of femtosecond pulses” in “a hollow-core fiber having a plurality of cores,” with spectral broadening occurring “separately in each core” (¶ 42). However, Klenke does not teach: “wherein the at least one optical functional element is arranged after the at least one optical amplifier in the beam path.” Rothhardt teaches that a high-power fiber chirped-pulse amplification system delivers the pulses, and that “subsequent spectral broadening in a xenon-filled hollow-core fiber and pulse compression with chirped mirrors” is used for pulse shortening and peak-power enhancement, i.e., expressly teaching subsequent broadening after the amplifier output.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the optical system of Klenke with the further teachings of Klenke and Rothhardt with a reasonable expectation for success in order to enable post-amplification spectral broadening at higher pulse energies by distributing the amplified beam among multiple cores, thereby keeping each broadening channel within its practical operating limits and increasing the spectral bandwidth of the system.
Regarding claim 21, Klenke in view of Rothhardt teaches the optical system of claim 18, and further teaches: wherein the optical functional element is a spectral broadening element formed as a multicore waveguide in which a plurality of waveguide structures is integrated, and wherein each waveguide structure carries one of the sub-beams (Klenke, ¶¶ 23, 42).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
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/ZHENGQING QI/Examiner, Art Unit 3645
/YUQING XIAO/Supervisory Patent Examiner, Art Unit 3645
1 Cui et al., "Spectral phase effects and control requirements of coherent beam combining for ultrashort ultrahigh intensity laser systems," Appl. Opt. 55, 10124-10132 (2016).
2 Klenke, A., et al. "Coherently combined 16-channel multicore fiber laser system." Optics Letters 43.7 (2018): 1519-1522.
3 Rothhardt, Jan, et al. "1 MHz repetition rate hollow fiber pulse compression to sub-100-fs duration at 100 W average power." Optics letters 36.23 (2011): 4605-4607.
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