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 .
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.
Claim Objections
Claim 5 objected to because of the following informalities: Claim 5 contains a period after the equation and at the end of the claim. Each claim must begin with a capital letter and end with a period. MPEP 608.01(m). Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 12 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 12 depends from claim 8 that depends from claim 1. Claim 12 recites “a portion of the core of Raman fiber amplifier that is outside of the GeO2 doping is doped with alumina (Al203).” Neither claim 8 nor claim 1 defines a Raman fiber amplifier with GeO2. Accordingly, the GeO2 doping lacks antecedent basis and it is unclear if applicant intends to define a GeO2 doping region in claim 12 or if the claim should depend from claim 11. For the purpose of this Office Action, the Office will interpret claim 12 to recite “a portion of the core of Raman fiber amplifier that is outside of a GeO2 doping is doped with alumina (Al2O3)”.
Claim Rejections - 35 USC § 103
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-5, 8, and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Yao et al. (CN210779481U), hereafter Yao, in view of Liu et al. (“High-Power Operation of Silica-Based Raman Fiber Amplifier at 2147 nm”), hereafter Liu, in further view of Marciante (WO2015057482A1), hereafter Marciante.
Regarding claim 1, Yao discloses a high-power Raman fiber laser (Title) comprising: a seed laser configured to operate in a first spectral window (Fig. 1 element 1; [0036]); a plurality of pump lasers, each including a cladding (Fig. 1 element 2; [0037]1) configured to operate in a spectral window ([0037]), a pump/seed combiner to combine outputs of the pump lasers and output of the seed laser (Fig. 1 element 3; Fig. 2; [0038]); the pump/seed combiner having a tapered portion including a cladding (Fig. 2 shows a combiner having an unlabeled cladding; [0038] describes the combiner as being tapered); and a Raman fiber amplifier having a core and a cladding surrounding the core (Fig. 1 element 4; [0040]), wherein the seed laser is launched into the core ([0005]; [0040]), and pump laser output beams are launched into the cladding ([0005]; [0011]). Yao does not explicitly disclose the fiber pump lasers comprising of thulium (Tm)doped fiber laser (TDFL), and configured to operate in a 1935-2020 nm spectral window; the Raman fiber amplifier configured to amplify the seed laser to produce an amplified output signal having a wavelength in the first spectral window, wherein a brightness of the cladding of the Raman fiber amplifier is configured to match to a combined brightness of the plurality of pump lasers. However, Liu discloses the fiber pump lasers comprising of thulium (Tm)doped fiber laser (TDFL) (Abstract “thulium-doped all-fiber MOPA”), and configured to operate in a 1935-2020 nm spectral window (Abstract “The 1963 nm thulium-doped all-fiber MOPA”); the Raman fiber amplifier configured to amplify the seed laser to produce an amplified output signal having a wavelength in the first spectral window (Abstract “a 2147 nm silica-based Raman fiber amplifier…seeded with a 2147 nm thulium-doped all-fiber laser at the same time”). An advantage is to provide the materials and wavelength for a large number of applications including LIDAR, gas sensing, and optical communication (Sec. 1 first full paragraph). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Yao with the fiber pump lasers comprising of thulium (Tm)doped fiber laser (TDFL), and configured to operate in a 1935-2020 nm spectral window; the Raman fiber amplifier configured to amplify the seed laser to produce an amplified output signal having a wavelength in the first spectral window as disclosed by Liu in order to provide the materials and wavelength for a large number of applications including LIDAR, gas sensing, and optical communication. Yao in view of Liu do not explicitly disclose wherein a brightness of the cladding of the Raman fiber amplifier is configured to match to a combined brightness of the plurality of pump lasers. However, Marciante discloses that the etendue of the Raman amplifier should be equal to the etendue of the pump source (Abstract). An advantage is to increase the pump intensity in the Raman amplifier ([0010]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu with a brightness of the cladding of the Raman fiber amplifier is configured to match to a combined brightness of the plurality of pump lasers as disclosed by Marciante in order to increase the pump intensity in the Raman amplifier.
Regarding claim 2, Liu further discloses the first spectral window comprises wavelengths in 2100-2200 nm range (Abstract). Yao in view of Liu in further view of Marciante do not explicitly disclose Tm-doping concentration of each of the plurality of pump lasers is equal or greater than 5% wt. However, the Office takes Official Notice that the optimization of dopant concentration is well known in the art in order to balance factors such as absorption and gain versus quenching and heat generation. Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Yao in view of Liu in further view of Marciante with Tm-doping concentration of each of the plurality of pump lasers is equal or greater than 5% wt, since it is known in the art to optimize the dopant concentration in order to balance factors such as absorption and gain versus quenching and heat generation and since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980).
Regarding claim 3, Yao further discloses maintaining the brightness at a fusion point between the combiner and the Raman fiber ([0008]). Additionally, Marciante discloses that the etendue of the Raman amplifier should be equal to the etendue of the pump source (Abstract) in order to increase the pump intensity in the Raman amplifier ([0010]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu in further view of Marciante with a brightness of the Raman fiber amplifier is configured to match to a brightness of the cladding of the tapered portion of the pump/seed combiner, since Yao discloses maintaining brightness at a fusion point between the combiner and the Raman fiber and Marciante discloses etendue of the Raman amplifier should be equal to the etendue of the pump source in order to increase the pump intensity in the Raman amplifier.
Regarding claim 4, Yao further discloses the pump/seed combiner is fusion-spliced with the Raman fiber amplifier ([0008]).
Regarding claim 5, Yao in view of Liu in further view of Marciante do not explicitly disclose a number of the plurality of pump lasers Nmax is given by:
N
m
a
x
=
d
r
*
N
A
R
d
T
D
F
L
*
N
A
T
D
F
L
2
where, dR and NAR denote the pump-cladding diameter and pump-cladding numerical aperture (NA) of the Raman fiber amplifier, and where dTDFL and NATDFL denote the core diameter and core NA of the terminal fiber in each of the pump TDFLs. However, Yao discloses optimizing the number of pump lasers (Compare the number of pump fibers in each of Fig. 2) and limiting the mode field mismatch between the beam combiner and Raman fiber ([0008]) in order to maintain the brightness of the laser ([0008]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu in further view of Marciante with a number of the plurality of pump lasers Nmax is given by:
N
m
a
x
=
d
r
*
N
A
R
d
T
D
F
L
*
N
A
T
D
F
L
2
where, dR and NAR denote the pump-cladding diameter and pump-cladding numerical aperture (NA) of the Raman fiber amplifier, and where dTDFL and NATDFL denote the core diameter and core NA of the terminal fiber in each of the pump TDFLs, since Yao discloses optimizing the number of pump lasers and limiting the mode field mismatch between the beam combiner and Raman fiber in order to maintain the brightness of the laser and since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980).
Regarding claim 8, Yao in view of Liu in further view of Marciante do not explicitly disclose a cladding-to-mode area ratio (CMAR) of the Raman fiber amplifier is selected to limit a cladding to mode diameter ratio between 2.5 - 2.8. However, the Office takes Official Notice that optimizing a cladding-to-mode area ratio (CMAR) of optical fibers is well known in the art in order to balance pump absorption efficiency in the fiber and ease of coupling light into the fiber. Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu in further view of Marciante with a cladding-to-mode area ratio (CMAR) of the Raman fiber amplifier is selected to limit a cladding to mode diameter ratio between 2.5 - 2.8, since it is known in the art to optimize a cladding-to-mode area ratio (CMAR) of optical fibers in order to balance pump absorption efficiency in the fiber and ease of coupling light into the fiber and since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980).
Regarding claim 9, Yao in view of Liu in further view of Marciante do not explicitly disclose the core of the Raman fiber amplifier has an effective fundamental-mode field diameter of 5µm or greater. However, the Office takes Official Notice that it is well known in the art to optimize the effective fundamental-mode field diameter of an optical fiber laser to balance coupling efficiency and increased bending losses. Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu in further view of Marciante with the core of the Raman fiber amplifier has an effective fundamental-mode field diameter of 5µm or greater as is known in the art in order to balance coupling efficiency and increased bending losses and since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980).
Claims 6 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Yao in view of Liu in further view of Marciante, as applied to claim 1, in further view of McCahon et al. (US20220239055A1), hereafter McCahon.
Regarding claim 6, Yao in view of Liu in further view of Marciante do not explicitly disclose the seed laser is configured to output a sequence of pulses having a duration of 1-3 nano seconds or shorter that are time-synchronized and temporally overlapped with pulses produced by the plurality of pump lasers. However, McCahon discloses the seed laser is configured to output a sequence of pulses having a duration of 1-3 nano seconds or shorter (Fig. 6 elements 620) that are time-synchronized and temporally overlapped with pulses produced by the plurality of pump lasers ([0060]). An advantage is to provide short high power pulses based on the intended use of the device ([0006]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu in further view of Marciante with the seed laser is configured to output a sequence of pulses having a duration of 1-3 nano seconds or shorter that are time-synchronized and temporally overlapped with pulses produced by the plurality of pump lasers as disclosed by McCahon in order to provide short high power pulses based on the intended use of the device.
Regarding claim 7, Yao in view of Liu in further view of Marciante in further view of McCahon do not explicitly disclose a pulse waveform corresponding to the sequence of pulses output by the seed laser comprises a high pulse repetition frequency of 100 MHz or higher and a pulse duty factor of 1% or higher. However, McCahon further discloses optimizing the pulse repetition rate and pulse duty factor based on intended use ([0055]-[0056]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu in further view of Marciante in further view of McCahon with a pulse waveform corresponding to the sequence of pulses output by the seed laser comprises a high pulse repetition frequency of 100 MHz or higher and a pulse duty factor of 1% or higher, since McCahon discloses optimizing the pulse repetition rate and pulse duty factor based on intended use and since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980).
Claims 10-13 are rejected under 35 U.S.C. 103 as being unpatentable over Yao in view of Liu in further view of Marciante, as applied to claim 1 and 8 above, in further view of Gapontsev et al. (WO2019013862A2), hereafter Gapontsev.
Regarding claim 10, Yao in view of Liu in further view of Marciante do not explicitly disclose the Raman fiber amplifier is configured such that a favored fundamental mode in the Raman fiber amplifier has a higher gain than any other mode in the Raman fiber amplifier. However, Gapontsev discloses the Raman fiber amplifier is configured such that a favored fundamental mode in the Raman fiber amplifier has a higher gain than any other mode in the Raman fiber amplifier ([0025]). An advantage is to select the desired mode of the device based on intended use ([0025]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu in further view of Marciante with the Raman fiber amplifier is configured such that a favored fundamental mode in the Raman fiber amplifier has a higher gain than any other mode in the Raman fiber amplifier as disclosed by Gapontsev in order to to select the desired mode of the device based on intended use.
Regarding claim 11, Yao in view of Liu in further view of Marciante do not explicitly disclose a central portion of the core of Raman fiber amplifier is doped with GeO2, and wherein a fraction of the core diameter including the GeO2 doping and a magnitude of the GeO2 concentration within the fraction of the core diameter, are both varied to achieve a desired gain filtering. However, Gapontsev discloses doping a central portion of the core of the Raman fiber amplifier with GeO2, wherein a fraction of the core diameter doped with GeO2 and a magnitude of the GeO2 concentration within the fraction of the core diameter are varied to achieve a desired gain filtering ([0025]). An advantage is to achieve higher gain for the fundamental mode ([0025]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu with doping a central portion of the core of the Raman fiber amplifier with GeO2, wherein a fraction of the core diameter doped with GeO2 and a magnitude of the GeO2 concentration within the fraction of the core diameter are varied to achieve a desired gain filtering as disclosed by Gapontsev in order to achieve higher gain for the fundamental mode.
Regarding claim 12, Yao in view of Liu in further view of Marciante do not explicitly disclose a portion of the core of Raman fiber amplifier that is outside of the GeO2 doping is doped with alumina (Al203). However, Gapontsev further discloses a portion of the core of Raman fiber amplifier is doped with GeO2 ([0025]). An advantage is to achieve higher gain for the fundamental mode ([0025]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu with a portion of the core of Raman fiber amplifier is doped with GeO2 as disclosed by Gapontsev in order to achieve higher gain for the fundamental mode. Yao in view of Liu in further view of Marciante in further view of Gapontsev do not explicitly disclose a portion of the core of Raman fiber amplifier that is outside of the GeO2 doping is doped with alumina (Al203). However, the Office takes Official Notice that doping with alumina is well known in the art to optimize the refractive index profile of optical fibers. Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu in further view of Marciante in further view of Gapontsev with a portion of the core of Raman fiber amplifier that is outside of the GeO2 doping is doped with alumina (Al203) as is known in the art in order to optimize the refractive index profile of the fiber.
Regarding claim 13, Gapontsev further discloses controlling gain filtering in the Raman fiber amplifier based on at least two of: GeO2 concentration in the core, spatial variation of the GeO2 concentration between a plurality of regions of the core, a pump-cladding refractive index, core and pump-cladding diameters, and the core and cladding numerical apertures ([0025]).
Claims 14, 15, and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Yao in view of Liu.
Regarding claim 14, Yao discloses a method for operating a high-power laser (Title), the method comprising: operating a seed laser in a first spectral window (Fig. 1 element 1; [0036]); operating a plurality of pump lasers in a second spectral window, each including a cladding (Fig. 1 element 2; [0037]2); combining outputs of the pump lasers and output of the seed laser using a pump/seed combiner (Fig. 1 element 3; Fig. 2; [0038]) having a tapered portion including a cladding (Fig. 2 shows a combiner having an unlabeled cladding; [0038] describes the combiner as being tapered); and amplifying the seed laser, using a Raman fiber amplifier having a core and a cladding surrounding the core (Fig. 1 element 4; [0040]), wherein the seed laser is launched into the core ([0005]; [0040]), and pump laser output beams are launched into the cladding ([0005]; [0011]). Yao does not explicitly disclose the pump lasers comprising of thulium-doped fiber laser (TDFL) and the raman laser to produce an amplified output signal having a wavelength in the first spectral window. However, Liu discloses the fiber pump lasers comprising of thulium (Tm)doped fiber laser (TDFL) (Abstract “thulium-doped all-fiber MOPA”), and the Raman fiber amplifier configured to amplify the seed laser to produce an amplified output signal having a wavelength in the first spectral window (Abstract “a 2147 nm silica-based Raman fiber amplifier…seeded with a 2147 nm thulium-doped all-fiber laser at the same time”). An advantage is to provide the materials and wavelength for a large number of applications including LIDAR, gas sensing, and optical communication (Sec. 1 first full paragraph). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Yao with the fiber pump lasers comprising of thulium (Tm)doped fiber laser (TDFL), and the Raman fiber amplifier configured to amplify the seed laser to produce an amplified output signal having a wavelength in the first spectral window as disclosed by Liu in order to provide the materials and wavelength for a large number of applications including LIDAR, gas sensing, and optical communication. Yao in view of Liu do not explicitly disclose wherein a brightness of the cladding of the Raman fiber amplifier is configured to match to a combined brightness of the plurality of pump lasers.
Regarding claim 15, Liu further discloses the first spectral window comprises wavelengths in 2100-2200 nm range (Abstract) and the second spectral window comprises wavelengths in 1935-2020 nm range (Abstract “The 1963 nm thulium-doped all-fiber MOPA”). Yao in view of Liu do not explicitly disclose Tm-doping concentration of each of the plurality of pump lasers is equal or greater than 5% wt. However, the Office takes Official Notice that the optimization of dopant concentration is well known in the art in order to balance factors such as absorption and gain versus quenching and heat generation. Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Yao in view of Liu with Tm-doping concentration of each of the plurality of pump lasers is equal or greater than 5% wt, since it is known in the art to optimize the dopant concentration in order to balance factors such as absorption and gain versus quenching and heat generation and since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980).
Regarding claim 18, Yao in view of Liu do not explicitly disclose a cladding-to-mode area ratio (CMAR) of the Raman fiber amplifier is selected to limit a cladding to mode diameter ratio between 2.5 - 2.8. However, the Office takes Official Notice that optimizing a cladding-to-mode area ratio (CMAR) of optical fibers is well known in the art in order to balance pump absorption efficiency in the fiber and ease of coupling light into the fiber. Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu with a cladding-to-mode area ratio (CMAR) of the Raman fiber amplifier is selected to limit a cladding to mode diameter ratio between 2.5 - 2.8, since it is known in the art to optimize a cladding-to-mode area ratio (CMAR) of optical fibers in order to balance pump absorption efficiency in the fiber and ease of coupling light into the fiber and since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980).
Claim 16 are rejected under 35 U.S.C. 103 as being unpatentable over Yao in view of Liu in further view of Marciante.
Regarding claim 16, Yao in view of Liu do not explicitly disclose a brightness of the pump cladding within the Raman fiber amplifier is configured to match to a combined brightness of the plurality of pump lasers. However, Marciante discloses that the etendue of the Raman amplifier should be equal to the etendue of the pump source (Abstract). An advantage is to increase the pump intensity in the Raman amplifier ([0010]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu with a brightness of the cladding of the Raman fiber amplifier is configured to match to a combined brightness of the plurality of pump lasers as disclosed by Marciante in order to increase the pump intensity in the Raman amplifier.
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Yao in view of Liu, as applied to claim 14, in further view of McCahon.
Regarding claim 17, Yao in view of Liu do not explicitly disclose the seed laser is configured to output a sequence of pulses having a duration of 1-3 nano seconds or shorter that are time-synchronized and temporally overlapped with pulses produced by the plurality of pump lasers. However, McCahon discloses the seed laser is configured to output a sequence of pulses having a duration of 1-3 nano seconds or shorter (Fig. 6 elements 620) that are time-synchronized and temporally overlapped with pulses produced by the plurality of pump lasers ([0060]). An advantage is to provide short high power pulses based on the intended use of the device ([0006]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu with the seed laser is configured to output a sequence of pulses having a duration of 1-3 nano seconds or shorter that are time-synchronized and temporally overlapped with pulses produced by the plurality of pump lasers as disclosed by McCahon in order to provide short high power pulses based on the intended use of the device.
Claims 19 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Yao in view of Liu in further view of Gapontsev.
Regarding claim 19, Yao in view of Liu do not explicitly disclose doping a central portion of the core of the Raman fiber amplifier with GeO2, wherein a fraction of the core diameter doped with GeO2 and a magnitude of the GeO2 concentration within the fraction of the core diameter are varied to achieve a desired gain filtering. However, Gapontsev discloses doping a central portion of the core of the Raman fiber amplifier with GeO2, wherein a fraction of the core diameter doped with GeO2 and a magnitude of the GeO2 concentration within the fraction of the core diameter are varied to achieve a desired gain filtering ([0025]). An advantage is to achieve higher gain for the fundamental mode ([0025]). Accordingly, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to further modify Yao in view of Liu with doping a central portion of the core of the Raman fiber amplifier with GeO2, wherein a fraction of the core diameter doped with GeO2 and a magnitude of the GeO2 concentration within the fraction of the core diameter are varied to achieve a desired gain filtering as disclosed by Gapontsev in order to achieve higher gain for the fundamental mode.
Regarding claim 20, Gapontsev further discloses controlling gain filtering in the Raman fiber amplifier based on at least two of: GeO2 concentration in the core, spatial variation of the GeO2 concentration between a plurality of regions of the core, a pump-cladding refractive index, core and pump-cladding diameters, and the core and cladding numerical apertures ([0025]).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. See attached Notice of References Cited.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOSHUA KING whose telephone number is (571)270-1441. The examiner can normally be reached Monday to Friday 10am-5pm MT.
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/Joshua King/ Primary Examiner, Art Unit 2828 09/27/2025
1 The Office notes that a person of ordinary skill in the art would understand the doped fiber lasers described in [0037] to have a cladding in order to form an optical fiber.
2 The Office notes that a person of ordinary skill in the art would understand the doped fiber lasers described in [0037] to have a cladding in order to form an optical fiber.