Prosecution Insights
Last updated: April 19, 2026
Application No. 18/097,577

SHORT FIBER LENGTH MULTI-CORE FIBER (MCF) ERBIUM-DOPED FIBER AMPLIFIERS (EDFAS)

Final Rejection §102§103§112
Filed
Jan 17, 2023
Examiner
HUGHES, DEANDRA M
Art Unit
3992
Tech Center
3900
Assignee
II-VI Delaware, Inc.
OA Round
2 (Final)
78%
Grant Probability
Favorable
3-4
OA Rounds
2y 9m
To Grant
97%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
138 granted / 177 resolved
+18.0% vs TC avg
Strong +19% interview lift
Without
With
+19.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
21 currently pending
Career history
198
Total Applications
across all art units

Statute-Specific Performance

§101
3.7%
-36.3% vs TC avg
§103
21.5%
-18.5% vs TC avg
§102
14.0%
-26.0% vs TC avg
§112
29.5%
-10.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 177 resolved cases

Office Action

§102 §103 §112
Non-Final Rejection Acknowledgements 1. Claims 1-18 were presented for examination on January 17, 2023. Claim 1 is independent. Claims 1-18 are examined. 2. Examiners do not find a claim of domestic or foreign priority. 3. The presumed effective filing date is January 17, 2023, which is the filing date of the instant application. Claim Rejections - 35 USC § 112 4. Claims 1-18 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, regards as the invention. A single claim which claims both an apparatus and the method steps of using the apparatus is indefinite under 35 U.S.C. 112(b). See MPEP §2173.05(p). The limitations “wherein the amplifying comprising applying a plurality of gain sections, with each gain section associated with a corresponding fiber length, and wherein applying one or more of the plurality of gain sections comprises use of one or more loops via one or more corresponding cores in the multiple-core fiber (MCF)” render the claim indefinite because it claims both the apparatus (i.e., “a fiber amplifier”) and method steps of using the apparatus (i.e., “use of one or more loops via one or more corresponding cores in the MCF”). Claims 2-18 are rejected based on their dependency on claim 1. In the interest of compact prosecution, this limitation will be examined as a multicore fiber amplifier where the topology (e.g., figure 3, #300) may incorporate use of multiple gain sections (loops) to reduce overall physical length. See e.g., ¶[0022]. Claim Rejections - 35 USC § 102 5. Claims 1-9 and 14-16 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by US 2022/0045473 to Matsumoto et al. published Feb. 10, 2022 (“Matsumoto”). PNG media_image1.png 684 1020 media_image1.png Greyscale As to claim 1, Matsumoto discloses “[a] fiber amplifier for amplifying signal light” in figure 1, as annotated by the Examiner. Matsumoto discloses “one or more pumps configured to pump light during the amplifying” at pumping light source (#140). Matsumoto discloses “a fiber doped with an active dopant for communicating the signal light within the fiber amplifier during the amplifying” because #B0 is an multi-core erbium-doped optical fiber. See ¶[0050]. Matsumoto discloses “wherein the fiber is in optical communication with the signal light and in optical communication with the one or more pumps” because #B0 is in optical communication with multi-core fiber #A0. Matsumoto discloses “wherein the fiber comprises a multiple-core fiber (MCF)” because #B0 has four cores (i.e., #B01, #B02, #B03, and #B04). As best understood, Matsumoto discloses the gain sections associated with a corresponding fiber length because each core (i.e., #B01, #B02, #B03, and #B04) is doped with erbium and each core necessarily has an associated fiber length. Moreover, Matsumoto teaches WDMs #121 and #122 demultiplexes the L-band (e.g., #OUT113 and #OUT123) and supplies it again to cores #B03 and #B04, respectively. PNG media_image2.png 244 426 media_image2.png Greyscale As to claim 2, Matsumoto discloses “the fiber comprises an Erbium-doped fiber (EDF)” at ¶[0050]. As to claim 3, Matsumoto discloses “the fiber amplifier is configured to apply gain adjustment before or after at least one loop” because the L-band is looped back into core #B03 or #B04 via #OUT113 or #OUT123, which are doped cores. As to claim 4, Matsumoto discloses “the fiber amplifier is configured to apply the gain adjustment as a fixed adjustment” because the gain length of the cores are fixed thereby applying a fixed gain adjustment. As to claims 5-8, Matsumoto discloses a variable optical attenuator to apply a variable gain adjustment. Thus, Matsumoto discloses the following: “wherein the fiber amplifier is configured to apply the gain adjustment as a variable and/or modifiable adjustment;” “a gain adjustment component configured to apply the gain adjustment;” “wherein the gain adjustment component comprises variable optical attenuator (VOA);” “wherein the fiber comprises a structural feature for enabling applying the gain adjustment.” As to claim 9, Matsumoto discloses “the structural feature comprises a splice between two loops within the multiple-core fiber (MCF)” because the loop (e.g., OUT113 or OUT123) is spliced between two cores (#B01 and #B03) and (#B02 and #B04). 12. The fiber amplifier of claim 1, wherein the one or more pumps comprise a single pump configured to pump light for two or more of the plurality of gain sections. As to claims 14 and 16, Matsumoto discloses “the fiber comprises a structure for enabling operation of a single pump to pump light for two or more of the plurality of gain sections” because MCF-EDFA #B0 is cladding pumped by #140. As to claim 15, Matsumoto discloses “wherein the structure comprises a cladding structure” because MCF-EDFA #B0 is cladding pumped by #140. Claim Rejections - 35 USC § 103 6. Claim 10 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Matsumoto in view of US 2022/0329035 to Zhang et al. published Oct. 13, 2022 (“Zhang’). Matsumoto does not specifically disclose “the structural feature comprises an altering of structure of the fiber similar to Bragg gratings.” Zhang, however, teaches altering the Bragg gratings of a MCF to achieve phase matching of the modes. Thus, it would have been obvious to one of ordinary skill in the art to modify the MCF with the Bragg gratings taught by Zhang for the advantage of phase matching. Matsumoto does not specifically disclose “wherein the single pump comprises a multi-mode pump.” Zhang, however, teaches the pump laser (#202) pumps the few-mode amplifier to pump the MCF. Thus, it would have been obvious to modify Matsumoto with the multi-mode pump of Zhang for the advantage of gain efficiency of the short length optical fiber amplifier. 7. Claims 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over Matsumoto in view of US 2022/0115830 to Yanagimachi et al. published April 14, 2022 (“Yanagimachi”). Matsumoto does not specifically disclose “a second pump configured to operate in conjunction with the single pump…wherein the second pump comprises a single-mode pump.” Yanagimachi, however, teaches multiple single mode pumps (figure 4, #55) pumping multiple respective cores of a MC-EDF (#51). Thus, it would have been obvious to one of ordinary skill in the art, at the time of the invention, to use the multiple single-mode pumps for pumping the cores of the MC-EDF for the advantage of gain efficiency. Allowable Subject Matter 8. Although claim 11 is rejected under §112(b), as best understood, this claim contains allowable subject matter and would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims and if the §112(b) rejection is overcome. Specifically, the prior art does not teach or make obvious “the use of loops comprises assigning a different number of loops to one of the plurality of gain sections compared to a number of loops assigned to another one of the plurality gain sections” in combination with the other limitations of the claims. Conclusion 9. Any inquiry concerning this communication or earlier communications from the examiner should be directed to DEANDRA M HUGHES whose telephone number is (571)272-6982. The examiner can normally be reached Generally M-Th 8AM-6PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Hetul Patel can be reached at 571-272-4184. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. Signed: /DEANDRA M HUGHES/Reexamination Specialist, Art Unit 3992
Read full office action

Prosecution Timeline

Jan 17, 2023
Application Filed
Dec 01, 2025
Non-Final Rejection — §102, §103, §112
Apr 02, 2026
Response Filed
Apr 15, 2026
Final Rejection — §102, §103, §112 (current)

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Prosecution Projections

3-4
Expected OA Rounds
78%
Grant Probability
97%
With Interview (+19.2%)
2y 9m
Median Time to Grant
Moderate
PTA Risk
Based on 177 resolved cases by this examiner. Grant probability derived from career allow rate.

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