CTNF 18/533,407 CTNF 95807 DETAILED ACTION Notice of Pre-AIA or AIA Status 07-03-aia AIA 15-10-aia The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA. Information Disclosure Statement The Information Disclosure Statement (lDS) submitted on 02/26/2024 is in compliance with the provisions of 37 CFR 1.97 and has been considered. Claim Objections 07-29-01 AIA Claim s 6, 9 and 11-21 are objected to because of the following informalities: Regarding claim 6, “LP 02 and” should read --LP 02 ) and--. Regarding claim 9, “an CC-MCF” should read --a CC-MCF--. Regarding claim 17, “LP 02 and” should read --LP 02 ) and--. Regarding claim 20, “an CC-MCF” should read --a CC-MCF--. Regarding claims 11-12 and 17-20, recitations of “the optical fiber” should read --the at least one optical fiber--. Claims 12-21 are further objected to by virtue of dependency . Appropriate correction is required. Claim Rejections - 35 USC § 112 07-30-02 AIA 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. 07-34-01 Claims 17-19 are 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 17 recites “N se =6 (LP 01 , L 11,a , LP 11,b , LP 21,a , LP 21,b , LP 02 …).” The term “L 11,a ” lacks reasonably clear meaning in the context of the claim because the surrounding claim language uses LP mode notation, including LP 01 , LP 11,b , LP 21,a , LP 21,b , and LP 02 . Thus, it is unclear whether applicant intended to recite the LP 11,a spatial mode or a different mode. For the purposes of examination, “L 11,a ” is understood to read --LP 11,a -- in accordance with Spec. ¶¶ 27, 30 & Table 1. Claim 18 recites “pump mode group 5 (LP 41,a , LP 41,b , LP 32,a , LP 32,b , LP 13,a , LP 13,b )” and “pump mode group 6 (LP 51,a , LP 51,b , LP 32,a , LP 32,b , LP 13,a , LP 13,b ).” Thus, claim 18 appears to assign LP 32,a , LP 32,b , LP 13,a , and LP 13,b to both pump mode group 5 and pump mode group 6, while omitting LP 22,a , LP 22,b , and LP 03 from pump mode group 5. As a result, the scope of the recited “pump mode group 5” is unclear. For purposes of examination only, “pump mode group 5” is understood to read --LP 41,a , LP 41,b , LP 22,a , LP 22,b , and LP 03 -- in accordance with Spec. ¶ 78 and corresponding apparatus claim 7. Claim 19 recites “a corresponding total number of pump spatial modes excited, given by N p =N c , is one of 2, 3, 4, 5 and 6.” The symbol “N p ” has no antecedent basis in claim 19 or in independent claim 11. Claim 11 instead defines “N pe ” as the integer specifying the number of guided pump spatial modes to be excited. Accordingly, it is unclear whether “N p ” in claim 19 is intended to refer to “N pe ” or to a different quantity. For purposes of examination only, “N p =N c ” is understood to read --N pe =N c -- in accordance with Spec. ¶¶ 31, 33, 35 and corresponding apparatus claim 8. Claim Rejections - 35 USC § 103 07-06 AIA 15-10-15 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. 07-20-aia AIA 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. 07-21-aia AIA Claim s 1-2, 10-13 and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Li (CN 108767636 A) in view of Lopez-Galmiche (“Few-mode erbium-doped fiber amplifier with photonic lantern for pump spatial mode control,” published 2016) 1 . Regarding claim 1 , Li discloses an optical fiber amplifier subsystem (Fig. 1; ¶¶ 14, 17, “an all-fiber type weakly coupled few-mode erbium-doped fiber amplifier” including “a mode selection coupler, a signal-pump combiner, and a few-mode erbium-doped fiber”), comprising: an optical fiber selected from the group consisting of a multimode fiber (MMF) and a coupled-core multi-core fiber (CC-MCF) (¶¶ 4, 15, 17, multimode fiber); a gain medium configured to provide gain for N se guided signal spatial modes in the optical fiber (¶ 36, signal and pump are coupled “into the few-mode erbium-doped fiber, thereby amplifying the mode division multiplexed signal light”); at least one pump light source configured to provide pump light [1: …] to the gain medium (¶¶ 15, 17, 36, “input single-mode pump light” converted by the mode selection coupler and coupled with the signal light into the few-mode erbium-doped fiber, where a pump light source in implicitly disclosed, as presence of pump light logically suggests a light source. See MPEP 2144.01); a pump coupler configured to perform propagation constant matching to effect mode-selective evanescent field coupling of the pump light to N pe guided pump modes in the optical fiber (¶0015, “all-fiber mode selection coupler” used “to convert single-mode pump light into a specific fundamental mode or higher-order mode in a few-mode fiber”; ¶ 22, coupler made by “fused taper method” and converts modes “based on phase matching conditions”; Fig. 2 and ¶ 36, cascaded mode selection couplers), [2: …] . Li does not expressly teach a specific numerical example in which N se and N pe satisfy N pe < N se and N pe > 1, nor does Li expressly identify the pump wavelength, specifically: (1) [pump light source configured to provide pump light] “at a pump wavelength”; and, (2) [a pump coupler] “where N se is an integer specifying a number of guided signal spatial modes to be excited and N pe is an integer specifying a number of guided pump spatial modes to be excited, and N pe <N se and N pe >1.” However, Lopez-Galmiche teaches (1) in p. 2589, Fig. 3, “two fiber-coupled 976 nm single-mode laser diodes were employed to pump the EDFA”; and further teaches (2) , where N se = 6 guided signal spatial modes (p. 2589, Fig. 1 and Table 1, “supports six LP modes (LP 01 , LP 11a , LP 11b , LP 21a , LP 21b , and LP 02 )”) and N pe = 2 guided pump modes (p. 2589, EDFA is pumped “by simultaneously injecting the LP 21a and LP 21b modes,” with “equal pump powers” launched to each mode; Abstract, “mode-selective forward pumping of the two degenerate LP21 modes operating at 976 nm”), thus teaching N pe <N se and N pe >1. 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 fiber amplifier subsystem of Li with the teachings of Lopez-Galmiche with a reasonable expectation of success in order to obtain the predictable benefit of reduced differential modal gain (Lopez-Galmiche, pp. 2588, 2590, Fig. 4(b), Abstract). Regarding claim 2 , Li in view of Lopez-Galmiche teaches the amplifier subsystem of claim 1, and further teaches: wherein the pump coupler is a fused glass pump coupler (Li, ¶ 22, the all-fiber mode selection coupler is “fabricated using a fused taper method”). Regarding claim 10 , Li in view of Lopez-Galmiche teaches the amplifier subsystem of claim 1, and further teaches: wherein the gain medium includes an erbium-doped fiber (Li, ¶¶ 17, 26). Regarding claim 11 , Li discloses a spatial-division multiplexing (SDM) optical transmission system (¶ 8, mode-division multiplexing in few-mode fiber, where each mode is used “as an independent channel signal”), comprising: first and second terminals (¶¶ 4, 36, transmission system having a “receiving end” and a transmission end where the post-amplified signal continues into the next fiber segment, wherein the endpoints of such an optical transmission system is understood to correspond to first and second terminals); an optical path operatively coupling the first terminal to the second terminal and including at least one optical fiber configured to support a plurality of spatial modes at a given optical wavelength (¶ 36, transmission through “few-mode fiber”; ¶ 8, mode-division multiplexing uses modes as independent channels); and at least one multimode optical amplifier subsystem disposed along the optical path for amplifying the plurality of spatial modes propagating in the optical fiber (¶ 36, long-distance mode-division multiplexing transmission system, after attenuation through few-mode fiber “it is necessary to connect a few-mode erbium-doped fiber amplifier for amplification,” and that the amplified mode-division multiplexed signal “enters the next segment of few-mode fiber for continued transmission”), the at least one multimode optical amplifier subsystem including: a gain medium configured to provide gain for N se guided signal spatial modes in the optical fiber (¶¶ 17, 36, “few-mode erbium-doped fiber” as the gain medium and signal-pump combiner injects the mode-division multiplexed signal light and converted pump light into the few-mode erbium-doped fiber “thereby amplifying the mode-division multiplexed signal light”); at least one pump light source configured to provide pump light [1: …] to the gain medium (¶¶ 15, 17, 36, input single-mode pump light converted by the mode selection coupler and coupled with the signal into the few-mode erbium-doped fiber, where a pump light source in implicitly disclosed, as presence of pump light logically suggests a light source. See MPEP 2144.01); a pump coupler configured to perform propagation constant matching to effect mode-selective evanescent field coupling of the pump light to N pe guided pump spatial modes in the optical fiber (¶ 15, all-fiber mode selection coupler that converts single-mode pump light into a selected fundamental or higher-order mode in few-mode fiber; ¶ 22, coupler is made by a “fused taper method” and performs mode conversion “based on phase matching conditions,”; Fig. 2 and ¶ 36, cascaded mode selection couplers), [2: …] . Li does not expressly teach a specific numerical example in which N se and N pe satisfy N pe < N se and N pe > 1, nor does Li expressly identify the pump wavelength, specifically: (1) [pump light source configured to provide pump light] “at a pump wavelength”; and, (2) [a pump coupler] “where N se is an integer specifying a number of guided signal spatial modes to be excited and N pe is an integer specifying a number of guided pump spatial modes to be excited, and N pe <N se and N pe >1.” However, Lopez-Galmiche teaches (1) in p. 2589, Fig. 3, “two fiber-coupled 976 nm single-mode laser diodes were employed to pump the EDFA”; and further teaches (2) , where N se = 6 guided signal spatial modes (p. 2589, Fig. 1 and Table 1, “supports six LP modes (LP 01 , LP 11a , LP 11b , LP 21a , LP 21b , and LP 02 )”) and N pe = 2 guided pump modes (p. 2589, EDFA is pumped “by simultaneously injecting the LP 21a and LP 21b modes,” with “equal pump powers” launched to each mode; Abstract, “mode-selective forward pumping of the two degenerate LP21 modes operating at 976 nm”), thus teaching N pe <N se and N pe >1. 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 fiber amplifier subsystem of Li with the teachings of Lopez-Galmiche with a reasonable expectation of success in order to obtain the predictable benefit of reduced differential modal gain (Lopez-Galmiche, pp. 2588, 2590, Fig. 4(b), Abstract). Regarding claim 12 , Li in view of Lopez-Galmiche teaches the optical transmission system of claim 11, and further teaches: wherein the optical fiber is selected from the group consisting of a multimode fiber (MMF) and a coupled-core multi-core fiber (CC-MCF) (Li, ¶ 4, “few-mode fiber as a new spatial multiplexing method”; ¶ 8, mode-division multiplexing in few-mode fiber using modes as independent channel signals). Regarding claim 13 , Li in view of Lopez-Galmiche teaches the optical transmission system of claim 11, and further teaches: wherein the pump coupler is a fused glass pump coupler (Li, ¶ 22, the all-fiber mode selection coupler is “fabricated using a fused taper method”). Regarding claim 21 , Li in view of Lopez-Galmiche teaches the optical transmission system of claim 11, and further teaches: wherein the gain medium includes an erbium-doped fiber (Li, ¶¶ 17, 26) . 07-21-aia AIA Claim s 3 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Li in view of Lopez-Galmiche further in view of Chen (US 20160033719 A1) . Regarding claim 3 , Li in view of Lopez-Galmiche teaches the amplifier subsystem of claim 1, however does not teach: wherein the pump coupler has a fiber core with a refractive index profile that renders unequal the propagation constants of different pump spatial modes that reside in common pump spatial mode groups to thereby provide mode-selective coupling. Chen teaches a multimode optical fiber directed to reducing mode degeneracy and explains that, for conventional circular-core LP 11 and LP 21 four-fold modes, “the propagation constants … are equal” even though their mode field profiles differ (¶¶ 1-2; Fig. 4, ¶¶ 36, 42). Chen then teaches introducing assistant cores to form a two-fold symmetric refractive index distribution, causing the original four-fold modes to split into X and Y modes, with the two split modes showing increased effective index difference (Figs. 1, 3-4, ¶¶ 29-30, 36, 42). Chen further teaches that increased index difference suppresses mode coupling and “can also ensure effective and selective mode coupling when it is applied to form fiber couplers” (Fig. 4, ¶¶ 31, 36, 42). 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 pump coupler of Li in view of Lopez-Galmiche with the teachings of Chen with a reasonable expectation of success in order to predictably improve the ability to selectively couple pump light into particular spatial pump modes while suppressing unwanted coupling among modes in common LP mode groups (Chen, ¶¶ 29-32, 36, 42). Regarding claim 14 , Li in view of Lopez-Galmiche teaches the optical transmission system of claim 11, however does not teach: wherein the pump coupler has a fiber core with a refractive index profile that renders unequal the propagation constants of different pump spatial modes that reside in common pump spatial mode groups to thereby provide mode-selective coupling. Chen teaches a multimode optical fiber directed to reducing mode degeneracy and explains that, for conventional circular-core LP 11 and LP 21 four-fold modes, “the propagation constants … are equal” even though their mode field profiles differ (¶¶ 1-2; Fig. 4, ¶¶ 36, 42). Chen then teaches introducing assistant cores to form a two-fold symmetric refractive index distribution, causing the original four-fold modes to split into X and Y modes, with the two split modes showing increased effective index difference (Figs. 1, 3-4, ¶¶ 29-30, 36, 42). Chen further teaches that increased index difference suppresses mode coupling and “can also ensure effective and selective mode coupling when it is applied to form fiber couplers” (Fig. 4, ¶¶ 31, 36, 42). 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 pump coupler of Li in view of Lopez-Galmiche with the teachings of Chen with a reasonable expectation of success in order to predictably improve the ability to selectively couple pump light into particular spatial pump modes while suppressing unwanted coupling among modes in common LP mode groups (Chen, ¶¶ 29-32, 36, 42) . 07-21-aia AIA Claim s 4 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Li in view of Lopez-Galmiche further in view of Frolov (US 20040156096 A1) . Regarding claim 4 , Li in view of Lopez-Galmiche teaches the amplifier subsystem of claim 1, and further teaches: wherein the at least one pump light source includes a plurality of […] light sources configured to launch pump light into different pump modes (Li, ¶¶ 21, 36, one or more cascaded mode selection couplers convert multiple input single-mode pump lights into different modes, as previously combined with Lopez-Galmiche, p. 2589, Fig. 3, “two fiber-coupled 976 nm single-mode laser diodes” pumping the EDFA by “simultaneously injecting the LP 21a and LP 21b modes,” with equal pump powers launched to each mode). Li in view of Lopez-Galmiche does not teach: [a plurality of] “mutually incoherent” [light sources]. Frolov teaches pump distribution from “one or more pump laser sources” into multiple amplifier/pump ports (¶¶ 4, 39, 44) where “two or more separate lasers emitting independently are usually mutually incoherent” (¶¶ 41, 51; Fig. 8). 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 at least one pump light source of Li in view of Lopez-Galmiche with the teachings of Frolov with a reasonable expectation of success in order to avoid additional phase locking hardware while preserving pump power and pump mode control (Frolov, ¶¶ 41-42, 44, 51). Regarding claim 15 , Li in view of Lopez-Galmiche teaches the optical transmission system of claim 11, and further teaches: wherein the at least one pump light source includes a plurality of […] light sources configured to launch pump light into different pump modes (Li, ¶¶ 21, 36, one or more cascaded mode selection couplers convert multiple input single-mode pump lights into different modes, as previously combined with Lopez-Galmiche, p. 2589, Fig. 3, “two fiber-coupled 976 nm single-mode laser diodes” pumping the EDFA by “simultaneously injecting the LP 21a and LP 21b modes,” with equal pump powers launched to each mode). Li in view of Lopez-Galmiche does not teach: [a plurality of] “mutually incoherent” [light sources]. Frolov teaches pump distribution from “one or more pump laser sources” into multiple amplifier/pump ports (¶¶ 4, 39, 44) where “two or more separate lasers emitting independently are usually mutually incoherent” (¶¶ 41, 51; Fig. 8). 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 at least one pump light source of Li in view of Lopez-Galmiche with the teachings of Frolov with a reasonable expectation of success in order to avoid additional phase locking hardware while preserving pump power and pump mode control (Frolov, ¶¶ 41-42, 44, 51) . 07-21-aia AIA Claim s 5-6 and 16-17 are rejected under 35 U.S.C. 103 as being unpatentable over Li in view of Lopez-Galmiche further in view of Kang (“Modelling of Multimode Erbium-doped Fibre Amplifiers for Mode-division Multiplexed Transmission Systems,” published 2015) 2 . Regarding claim 5 , Li in view of Lopez-Galmiche teaches the amplifier subsystem of claim 1, however does not teach: wherein the gain medium includes one or more dopants distributed such that the gain medium has a doping profile, wherein the doping profile is a result of having been designed jointly with the powers of the respective pump modes. Kang teaches a multimode EDFA design in which DMG results from overlap among “pump modes, the signal modes and the distribution of the erbium dopant,” and teaches selecting LP 01p and LP 41p pump modes because they overlap central- and ring-doped regions, respectively (Chapter 5, §5.1.1, pp. 93-94); further teaching that large gain differences can be addressed by shaping the erbium-doping profile and that small gain differences can be managed by “fine tuning the power ratio between the two pump modes LP 01p and LP 41p ” (Chapter 5, §5.1.1, p. 95). 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 gain medium of Li in view of Lopez-Galmiche with the teachings of Kang with a reasonable expectation of success in order to improve gain equalization among the guided signal spatial modes (Kang, Chapter 5, §5.1, pp. 93-96). Regarding claim 6 , Li in view of Lopez-Galmiche teaches the amplifier subsystem of claim 1, however does not teach: wherein the optical fiber is an MMF in which N se =6 (LP 01 , LP 11,a , LP 11,b , LP 21,a , LP 21,b , LP 02 and the guided pump modes include modes from at least one of pump mode group 4 (LP 31,a , LP 31,b , LP 12,a , LP 12,b ) and pump mode group 5 (LP 41,a , LP 41,b , LP 22,a , LP 22,b , LP 03 ). Kang teaches on p. 113 the optical fiber is an MMF in which N se = 6 (LP 01 , LP 11,a , LP 11,b , LP 21,a , LP 21,b , LP 02 ) and further teaches at least one of pump mode from guided pump mode group 5 on p. 114, “LP 01p and LP 41p are chosen to efficiently pump the 4-mode-group EDF”; Fig. 5.1). 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 fiber of Li in view of Lopez-Galmiche with the teachings of Kang with a reasonable expectation of success in order to improve gain equalization among the guided signal spatial modes (Kang, Chapter 5, §5.1, pp. 93-96; §5.2, p. 97). Regarding claim 16 , Li in view of Lopez-Galmiche teaches the optical transmission system of claim 11, however does not teach: wherein the gain medium includes one or more dopants distributed such that the gain medium has a doping profile, wherein the doping profile is a result of having been designed jointly with the powers of the respective pump modes. Kang teaches a multimode EDFA design in which DMG results from overlap among “pump modes, the signal modes and the distribution of the erbium dopant,” and teaches selecting LP 01p and LP 41p pump modes because they overlap central- and ring-doped regions, respectively (Chapter 5, §5.1.1, pp. 93-94); further teaching that large gain differences can be addressed by shaping the erbium-doping profile and that small gain differences can be managed by “fine tuning the power ratio between the two pump modes LP 01p and LP 41p ” (Chapter 5, §5.1.1, p. 95). 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 gain medium of Li in view of Lopez-Galmiche with the teachings of Kang with a reasonable expectation of success in order to improve gain equalization among the guided signal spatial modes (Kang, Chapter 5, §5.1, pp. 93-96). Regarding claim 17 , Li in view of Lopez-Galmiche teaches the optical transmission system of claim 11, however does not teach: wherein the optical fiber is an MMF in which N se =6 (LP 01 , L 11,a , LP 11,b , LP 21,a , LP 21,b , LP 02 and the guided pump modes include modes from at least one of pump mode group 4 (LP 31,a , LP 31,b , LP 12,a , LP 12,b ) and pump mode group 5 (LP 41,a , LP 41,b , LP 22,a , LP 22,b , LP 03 ). Kang teaches on p. 113 the optical fiber is an MMF in which N se = 6 (LP 01 , LP 11,a , LP 11,b , LP 21,a , LP 21,b , LP 02 ) and further teaches at least one of pump mode from guided pump mode group 5 on p. 114, “LP 01p and LP 41p are chosen to efficiently pump the 4-mode-group EDF”; Fig. 5.1). 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 fiber of Li in view of Lopez-Galmiche with the teachings of Kang with a reasonable expectation of success in order to improve gain equalization among the guided signal spatial modes (Kang, Chapter 5, §5.1, pp. 93-96; §5.2, p. 97) . 07-21-aia AIA Claim s 7 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Li in view of Lopez-Galmiche further in view of Ono (US 20210257802 A1) . Regarding claim 7 , Li in view of Lopez-Galmiche teaches the amplifier subsystem of claim 1, however does not teach: wherein the optical fiber is an MMF in which N se =10 (LP 01 , LP 11,a , LP 11,b , LP 21,a , LP 21,b , LP 02 , LP 31,a , LP 31,b , LP 12,a , LP 12,b ) and the guided pump modes include modes from at least one of pump mode group 5 (LP 41,a , LP 41,b , LP 22,a , LP 22,b , LP 03 ) and pump mode group 6 (LP 51,a , LP 51,b , LP 32,a , LP 32,b , LP 13,a , LP 13,b ). Ono teaches an erbium-doped multimode optical amplifier (¶¶ 19, 22) whose signal light propagates ten modes when odd/even modes are distinguished: LP 01 , LP 11o , LP 11e , LP 21o , LP 21e , LP 02 , LP 31o , LP 31e , LP 12o , and LP 12e (¶ 22) with odd/even mapping broadly to the claim’s a/b notation (¶¶ 25, 27). Ono further teaches that the excitation light may propagate as LP 41 , LP 22 , and LP 03 (¶ 41) and that a mixed pump/excitation mode may include one, two, or three modes from LP 41o/e , LP 22o/e , and LP 03 (¶ 41). 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 fiber of Li in view of Lopez-Galmiche with the teachings of Ono with a reasonable expectation of success in order to reduce inter-mode gain deviation in long-haul MDM optical transmission (Ono, ¶¶ 22, 25, 41). Regarding claim 18 , Li in view of Lopez-Galmiche teaches the optical transmission system of claim 11, however does not teach: wherein the optical fiber is an MMF in which N se =10 (LP 01 , LP 11,a , LP 11,b , LP 21,a , LP 21,b , LP 02 , LP 31,a , LP 31,b , LP 12,a , LP 12,b ) and the guided pump modes include modes from at least one of pump mode group 5 (LP 41,a , LP 41,b , LP 32,a , LP 32,b , LP 13,a , LP 13,b ) and pump mode group 6 (LP 51,a , LP 51,b , LP 32,a , LP 32,b , LP 13,a , LP 13,b ). Ono teaches an erbium-doped multimode optical amplifier (¶¶ 19, 22) whose signal light propagates ten modes when odd/even modes are distinguished: LP 01 , LP 11o , LP 11e , LP 21o , LP 21e , LP 02 , LP 31o , LP 31e , LP 12o , and LP 12e (¶ 22) with odd/even mapping broadly to the claim’s a/b notation (¶¶ 25, 27). Ono further teaches that the excitation light may propagate as LP 41 , LP 22 , and LP 03 (¶ 41) and that a mixed pump/excitation mode may include one, two, or three modes from LP 41o/e , LP 22o/e , and LP 03 (¶ 41). 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 fiber of Li in view of Lopez-Galmiche with the teachings of Ono with a reasonable expectation of success in order to reduce inter-mode gain deviation in long-haul MDM optical transmission (Ono, ¶¶ 22, 25, 41) . Allowable Subject Matter Claims 8-9 and 20 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Claim 19 would be allowable if rewritten to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA), 2nd paragraph, set forth in this Office action and to include all of the limitations of the base claim and any intervening claims. A statement of reasons for the indication of allowable subject matter are as follows. The references of record, whether considered individually or in any reasonable combination, do not teach or suggest the optical fiber amplifier subsystem of claim 1, further comprising: a coupled-core multi-core fiber (CC-MCF) in which a number of cores N c is one of 2, 3, 4, 5, and 6; signal spatial supermodes associated with LP 11 ,a and LP 11,b excited such that N se = 2N c is one of 4, 6, 8, 10, and 12; and pump spatial modes associated with an axially symmetric mode excited such that N pe = N c is one of 2, 3, 4, 5, and 6, as recited in claim 8. Nor do the references teach or suggest the optical fiber amplifier subsystem of claim 1, further comprising: a CC-MCF in which N c is one of 2, 3, 4, 5, and 6; signal spatial supermodes associated with LP 01 , LP 11,a , and LP 11,b excited such that N se = 3N c is one of 6, 9, 12, 15, and 18; and pump spatial modes associated with an axially symmetric mode excited such that N pe = N c is one of 2, 3, 4, 5, and 6, as recited in claim 9. Further, the references of record, whether considered individually or in any reasonable combination, do not teach or suggest the SDM optical transmission system of claim 11, further comprising the corresponding CC- MCF limitations of claims 19 and 20, corresponding to the optical fiber amplifier subsystem of claims 8 and 9, respectively. Li teaches the mode selection coupler converts single-mode pump light into a selected mode of a few-mode fiber, and that multiple pump lights may be converted to different modes in a few-mode fiber by cascaded mode selection couplers. However, Li does not teach employment of the supermodes of a coupled-core multi-core fiber, and remains silent towards an N c core-count relationship of N se = 2N c or N se = 3N c , where N pe = N c for axially symmetric pump spatial. Lopez-Galmiche teaches a six-mode few-mode erbium-doped fiber amplifier using a mode-selective photonic lantern for pump spatial mode control. Although Lopez-Galmiche discusses SDM generally, including few-mode fibers, multimode fibers, and multicore fibers, it does not teach the claimed CC-MCF structure, the claimed coupled-core signal supermodes associated with LP11 a /LP 11b or LP 01 /LP 11a /LP 11b , or the claimed axially symmetric pump spatial modes having a pump-mode count equal to N c . Chen, Frolov, Kang and Ono fail to remedy the deficiencies of Li and Lopez-Galmiche. 07-96 The remaining prior art made of record and not relied upon is considered pertinent to applicant’s disclosure. Bai (US 20120262780 A1) discloses a multimode optical amplifier for MDM systems including a “pump preparation module” providing “a plurality of pump modes,” an amplification module accepting a multimode signal and pump output, and a gain control module for adjusting pump-mode balance (¶¶ 7-10, 24-25); however, does not disclose the CC-MCF supermode relationships of claims 8-9 and 19-20. Chang (US 9240667 B2) discloses an optical pumping apparatus for few-mode fiber amplification, including an optical pump source, optical power divider, modal multiplexer, few-mode fiber amplifier, and application of a multiplexed optical pump to modes of the few-mode fiber amplifier to reduce gain difference among modes (Col. 1:35-60; Col. 5:3-36; Figs. 6-7); however, does not disclose the claimed CC-MCF supermode relationships of claims 8-9 and 19-20. In sum, the cited prior art lacks any teaching or motivation that would lead a person of ordinary skill in the art to implement the features of claims 8-9 and 19-20, thereby failing to render the claimed invention anticipated or obvious. Accordingly, claims 8-9 and 20 would be allowable if rewritten in independent form, including all limitations of its base claim and any intervening claims. Claim 19 would be allowable if rewritten to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA), 2nd paragraph, set forth in this Office action and to include all of the limitations of the base claim and any intervening claims. 07-43-03 AIA As allowable subject matter has been indicated, applicant's reply must either comply with all formal requirements or specifically traverse each requirement not complied with. See 37 CFR 1.111(b) and MPEP § 707.07(a). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ZHENGQING QI whose telephone number is 571-272-1078. The examiner can normally be reached Monday - Friday 9:00 AM - 5:00 PM ET. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. 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If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ZHENGQING QI/Examiner, Art Unit 3645 Application/Control Number: 18/533,407 Page 2 Art Unit: 3645 Application/Control Number: 18/533,407 Page 3 Art Unit: 3645 Application/Control Number: 18/533,407 Page 4 Art Unit: 3645 Application/Control Number: 18/533,407 Page 5 Art Unit: 3645 Application/Control Number: 18/533,407 Page 6 Art Unit: 3645 Application/Control Number: 18/533,407 Page 7 Art Unit: 3645 Application/Control Number: 18/533,407 Page 8 Art Unit: 3645 Application/Control Number: 18/533,407 Page 9 Art Unit: 3645 Application/Control Number: 18/533,407 Page 10 Art Unit: 3645 Application/Control Number: 18/533,407 Page 11 Art Unit: 3645 Application/Control Number: 18/533,407 Page 12 Art Unit: 3645 Application/Control Number: 18/533,407 Page 13 Art Unit: 3645 Application/Control Number: 18/533,407 Page 14 Art Unit: 3645 Application/Control Number: 18/533,407 Page 15 Art Unit: 3645 Application/Control Number: 18/533,407 Page 16 Art Unit: 3645 Application/Control Number: 18/533,407 Page 17 Art Unit: 3645 Application/Control Number: 18/533,407 Page 18 Art Unit: 3645 Application/Control Number: 18/533,407 Page 19 Art Unit: 3645 Application/Control Number: 18/533,407 Page 20 Art Unit: 3645 Application/Control Number: 18/533,407 Page 21 Art Unit: 3645 1 G. Lopez-Galmiche, Z. Sanjabi Eznaveh, J. E. Antonio-Lopez, A. M. Velazquez Benitez, J. Rodriguez Asomoza, J. J. Sanchez Mondragon, C. Gonnet, P. Sillard, G. Li, A. Schülzgen, C. M. Okonkwo, and R. Amezcua Correa, “Few-mode erbium-doped fiber amplifier with photonic lantern for pump spatial mode control,” Opt. Lett. 41, 2588-2591 (2016). 2 Kang, Qiongyue (2015) “Modelling of Multimode Erbium-doped Fibre Amplifiers for Mode-division Multiplexed Transmission Systems.” University of Southampton, Optoelectronics Research Centre, PhD thesis, 182 pp.
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