Prosecution Insights
Last updated: April 19, 2026
Application No. 19/219,402

PROCESS TO PRODUCE MULTICORE OPTICAL FIBER PREFORM

Non-Final OA §103§112
Filed
May 27, 2025
Examiner
HERRING, LISA L
Art Unit
1741
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Corning Incorporated
OA Round
3 (Non-Final)
72%
Grant Probability
Favorable
3-4
OA Rounds
2y 10m
To Grant
89%
With Interview

Examiner Intelligence

Grants 72% — above average
72%
Career Allow Rate
587 granted / 810 resolved
+7.5% vs TC avg
Strong +17% interview lift
Without
With
+16.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
28 currently pending
Career history
838
Total Applications
across all art units

Statute-Specific Performance

§101
1.0%
-39.0% vs TC avg
§103
47.0%
+7.0% vs TC avg
§102
5.5%
-34.5% vs TC avg
§112
35.4%
-4.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 810 resolved cases

Office Action

§103 §112
DETAILED ACTION 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. 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 . Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on Jan. 22, 2026 has been entered. The Examiner notes in the response to the advisory action dated Jan. 9, 2026, the claims filed in the after final response dated Dec. 15, 2025, were entered by the Examiner. Specification The lengthy specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification. Claim Rejections - 35 USC § 112 The Examiner notes in the response to the advisory action dated Jan. 9, 2026, the claims filed in the after final response dated Dec. 15, 2025, were entered by the Examiner and this amendment was sufficient for the Examiner to withdraw the rejection of claim 6, under 35 U.S.C. 112(b) in the advisory action dated Jan. 9, 2026. Response to Arguments Applicant’s arguments with respect to claim(s) the prior art rejection in the final office action dated Oct. 24, 2025 have been considered, but are moot due to new grounds of rejection necessitated by the amendment filed Jan. 22, 2026. A new reference has been applied in the prior art rejection below. 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. Claim(s) 19-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Pandey et al. (US 2022/0315474A1 – hereinafter Pandey) in view of Chiba (JP2011-162392A), Wei et al. (CN103241937A – hereinafter Wei), and Kajikawa et al. (“Characteristics of Over 600-km-Long 4-core MCF Drawn from a Single Preform”, Conference: 2023 Optical Fiber Communications Conference and Exhibition (OFC), Conference date March 2023, Date Added to IEEE Xplore May 19, 2023, 3 pages). For the Chiba reference, the Examiner is referencing pages of the machine translation attached to the office action dated Jul. 17, 2025. Regarding claim 19, Pandey (Fig. 2, abstract, and [0083]) discloses a method of forming a multicore fiber including a plurality of discs with a plurality of core rods inserted in each disc (corresponding to a sleeve). Pandey ([0069], [0077], [0083]) discloses each of the discs includes a plurality of through holes that includes a plurality of core rods having a length 114, and ([0018]) discloses drilling the plurality of through holes in each disc. Pandey ([0081]) further discloses the sleeve (i.e. disc 104) made of silica glass. Based on the disclosures above, Pandey provides for forming a plurality of core cane holes within a sleeve (disc 104) and the sleeve is a silica-based glass. Pandey fails to disclose heating a sleeve blank above its softening temperature and molding the heated sleeve blank within a mold to form a sleeve (i.e. disc) so that exterior surfaces of the sleeve assume the shape of the mold, and the sleeve blank comprising non-uniform and undulating exterior surfaces along at least a portion of the exterior surfaces of the sleeve blank such that exterior surfaces of the sleeve being relatively more uniform than exterior surfaces of the sleeve blank. However, Chiba (pg. 2 and Figs 1a-1d) discloses a method of molding a quartz glass into a cylindrical shape, which is similar to the disc shape of Pandey. Chiba also discloses heating and melting a quartz glass bulk or ingot (corresponding to a sleeve blank) to a temperature ranging from 1500 degrees C to 2000 degrees C and molding the heated sleeve blank within a mold (“outer cylinder 14” and “bottom plate 12”) such that the quartz glass molded body has the same dimensions as the inner diameter of the outer cylinder. Additionally, Kajikawa (Fig. 1 and pg. 1) teaches a glass made from an OVD process and in Fig. 1 illustrates the glass made from the process has an undulating wavy exterior surface. Accordingly, based on the additional teachings by Chiba and Kajikawa, it would be obvious to a person having ordinary skill in the art, the sleeve (i.e. disc 104) of Pandey prior to forming a plurality of core can holes within the sleeve could be formed by heating and melting a quartz bulk or ingot, such as a blank supplied from an OVD process, as taught by Kajikawa, within a mold such that the molded body has the same dimensions as the inner diameter of the outer cylinder. The modified method of Pandey in view of Chiba and Kajikawa provides for the claimed step of heating a sleeve blank, as claimed, and the sleeve blank comprising non-uniform and undulating exterior surfaces along at least a portion of the exterior surfaces of the sleeve blank. The combination of Pandey in view of Chiba and Kajikawa, is merely combining prior art elements according to known methods yield predictable results Pandey in view of Chiba and Kajikawa fails to disclose the exterior surfaces of the sleeve are relatively more uniform than the exterior surfaces of the sleeve blank. However, Wei ([0004] teaches molding an optical fiber preform rod and teaches an adjustable casting mold to greatly increase the uniformity of the preform rod casting improves the optical performance of the preform rod. The method of Pandey in view of Chiba and Kajikawa and the method of Wei provides for molding a component of an optical fiber preform. Accordingly, based on the additional teachings that uniformity of a cast preform for an optical fiber greatly improves optical performance, it would be obvious to a person having ordinary skill in the art, in the method of Pandey in view of Chiba and Kajikawa, the optical performance of the molded sleeve for the optical fiber preform in the modified method could be improved by increasing the uniformity of the molded sleeve. In the process of increasing the uniformity of the molded sleeve in the modified method of Pandey, it would be obvious to a person having ordinary skill in the art, the uniformity of all surfaces, including the exterior surfaces of the molded sleeve, being relatively more uniform than the non-uniform and undulating exterior surfaces of the OVD sleeve blank to provide for improved optical performance. Regarding claim 20, as discussed in the rejection of claim 19 above, Pandey discloses each disc (i.e. sleeve) includes a plurality of through holes that includes a plurality of core rods. Additionally, Pandey (abstract) further discloses a plurality of core rods inserted in a plurality of through holes in each disc (i.e. sleeve). Pandey ([0082]) also discloses the plurality of core rods may be made of up-dopant pure silica (corresponding to a core region), such as a Ge doped silica glass or made of up-dopant pure silica surrounded by down doped regions. Based on the disclosures by Pandey, it would be obvious to a person having ordinary skill in the art, the modified method of Pandey provides for inserting a core cane through each of the core cane holes, the core canes being formed each being formed of silica-based glass and the core-canes each comprising a core region. Regarding claims 21 and 22, as discussed in the rejection of claim 19 above, Chiba teaches melting a quartz glass bulk or ingot (corresponding to a sleeve blank) to a temperature ranging from 1500 degrees C to 2000 degrees C and molding the heated sleeve blank within a mold (“outer cylinder 14” and “bottom plate 12”) such that the quartz glass molded body has the same dimensions as the inner diameter of the outer cylinder. Accordingly, it would be obvious to a person having ordinary skill in the art, the modified method of Pandey provides for a melting temperature of 1500-2000 degrees C, which includes temperatures above a softening temperature, and since it is heated for melting includes heating the sleeve blank to a temperature in an overlapping range of 1500-2000 degrees C, which overlaps Applicant’s claimed range of about 1700 degrees C and greater, as claimed in claim 21, and heating the sleeve blank to a temperature have values within Applicant’s claimed range of about 2000 degrees C or less, as claimed in claim 22. Allowable Subject Matter Claims 1-3, 5-13, 17-18 is/are allowed. The following is a statement of reasons for the indication of allowable subject matter is discussed below. Regarding claims 1-3, 5-13, and 17-18, the prior fails to disclose or fairly suggest the method step of claim 1 including positioning a sleeve blank within a mold, the sleeve blank comprising a plurality of precursor core cane holes and the mold comprising a plurality of rods in combination with the remaining claimed steps of positioning, heating and molding, and inserting as claimed. Please see the applied prior art in non-final rejection dated Jul. 17, 2025. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to LISA HERRING whose telephone number is (571)270-1623. The examiner can normally be reached M-F: EST 6:00am-3:00pm. 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, Alison Hindenlang can be reached at 571-270-7001. 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. /LISA L HERRING/Primary Examiner, Art Unit 1741
Read full office action

Prosecution Timeline

May 27, 2025
Application Filed
Jul 15, 2025
Non-Final Rejection — §103, §112
Sep 18, 2025
Applicant Interview (Telephonic)
Sep 18, 2025
Examiner Interview Summary
Oct 13, 2025
Response Filed
Oct 22, 2025
Final Rejection — §103, §112
Dec 15, 2025
Response after Non-Final Action
Jan 22, 2026
Request for Continued Examination
Jan 28, 2026
Response after Non-Final Action
Feb 20, 2026
Non-Final Rejection — §103, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12595203
OPTICAL FIBER GLASS PREFORM AND METHOD FOR MANUFACTURING OPTICAL FIBER GLASS PREFORM
2y 5m to grant Granted Apr 07, 2026
Patent 12577141
GLASS AND METHOD FOR PRODUCING THE SAME, AND MEMBER AND APPARATUS USING THE SAME
2y 5m to grant Granted Mar 17, 2026
Patent 12578525
OPTICAL FIBER WITH INVERSE TRIANGULAR TRENCH DESIGN
2y 5m to grant Granted Mar 17, 2026
Patent 12577142
HEAT CHAMFERING APPARATUS AND METHOD
2y 5m to grant Granted Mar 17, 2026
Patent 12570566
OPTICAL FIBER MANUFACTURING METHOD AND APPARATUS
2y 5m to grant Granted Mar 10, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
72%
Grant Probability
89%
With Interview (+16.9%)
2y 10m
Median Time to Grant
High
PTA Risk
Based on 810 resolved cases by this examiner. Grant probability derived from career allow rate.

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