Prosecution Insights
Last updated: April 19, 2026
Application No. 17/553,133

OPTIMIZED CORE PARTICLES FOR OPTICAL FIBER PREFORM AND OPTICAL FIBER PREFORM THEREOF

Non-Final OA §103§112
Filed
Dec 16, 2021
Examiner
DEHGHAN, QUEENIE S
Art Unit
1741
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Sterlite Technologies Limited
OA Round
6 (Non-Final)
62%
Grant Probability
Moderate
6-7
OA Rounds
3y 5m
To Grant
73%
With Interview

Examiner Intelligence

Grants 62% of resolved cases
62%
Career Allow Rate
519 granted / 839 resolved
-3.1% vs TC avg
Moderate +11% lift
Without
With
+11.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 5m
Avg Prosecution
52 currently pending
Career history
891
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
52.9%
+12.9% vs TC avg
§102
13.2%
-26.8% vs TC avg
§112
26.1%
-13.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 839 resolved cases

Office Action

§103 §112
DETAILED ACTION 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 July 28, 2025 has been entered. Priority Acknowledgment is made of applicant's claim for foreign priority based on an application filed in Europe on August 27, 2021. Applicant has not filed a certified copy of the EP 20748402.3 application as required by 37 CFR 1.55. Because a certified copy of the foreign priority has not been provided, the earliest filing date recognized by the office is December 16, 2021. 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 7 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 7 recites the powder-in-cylinder assists in stretching the optical fiber preform. The powder in cylinder technique is understood to involve inserting core particles inside a cladding tube. Thus, it is unclear how this technique “assist in stretching a preform”. Please clarify. 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. Claims 1, 4, 6-8 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Prasad et al. (WO 2020157766) in view of Bi et al. (2005/0019504). Prasad teaches a method for manufacturing an optical fiber preform comprising steps of optimizing the size of particles of calcium aluminum silicate powder to form optimized core particles, filling the inside of a fluorine doped glass tube with the optimized core particles, sintering the optimized core particles inside the fluorine doped glass tube such that the particles adhere smoothly with the tube, thereby forming an optical fiber preform, and drawing an optical fiber from the optical fiber preform (abstract, [0002], [0008], [0009]), wherein the calcium aluminum silicate powder forms a core section of the preform and the fluorine dopes glass tube forms a cladding section of the optical fiber preform ([0008]). Furthermore, Prasad teaches the core section has a low attenuation of about 0.1 decibel per kilometer ([0010]). While Prasad doesn’t specify the wavelength for measuring attenuation of the optical fiber, it would have been obvious to one of ordinary skill in the art to have measured the attenuation of the optical fiber measured at 1550nm, as it is known to be a common operating wavelength for optical fibers. This further exemplified by Bi, who teaches producing core particles for an optical fiber preform ([0047]). Bi further teaches the core particles can be expected to produce a core section characterized by low attenuation of less than or equal to 0.1 dB/km at 1550 nm ([0224]). Regarding claim 4, Prasad teaches the optimized core particles has a diameter in the range of about 30 microns to 50 microns ([0009]). Regarding claim 6, Prasad teaches the preform is manufacture by a powder-in-cylinder technique ([0012]). Regarding claim 7, Prasad teaches the optical fiber preform is stretched to form a plurality of solid preform rods having a diameter smaller than the optical fiber preform ([0012],[0028]). Regarding claim 8, Prasad teaches sintering at a temperature in the range of 1500°C-1600°C ([0013]). Regarding claim 10, Prasad teaches the fluorine doped glass tube has low viscosity as compared to non-doped glass ([0011], [0027]). Response to Arguments Applicant's arguments July 28, 2025 have been fully considered but they are not persuasive. Applicant argues the instant application has a priority date of January 29, 2019 and the cited reference, WO 2020157766, has priority of January 29, 2019. The office does not recognize a priority to an Indian application Number 201911003616 with a priority date of January 29, 2019. Instead, the recognized priority date is August 27, 2021. Please note the petition was dismissed. Since the publication date of WO 2020157766 is August 6, 2020, it is more than one year before the recognized filing date of August 27, 2021, which makes it a valid prior art, even if filed by the same inventor. Applicant noted a declaration in their arguments. However, no declaration was received. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to QUEENIE S DEHGHAN whose telephone number is (571)272-8209. The examiner can normally be reached Monday-Friday 8:00-4:30. 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 on 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. /QUEENIE S DEHGHAN/Primary Examiner, Art Unit 1741
Read full office action

Prosecution Timeline

Dec 16, 2021
Application Filed
Aug 11, 2023
Non-Final Rejection — §103, §112
Nov 14, 2023
Response Filed
Jan 18, 2024
Final Rejection — §103, §112
Apr 16, 2024
Request for Continued Examination
Apr 17, 2024
Response after Non-Final Action
Jun 11, 2024
Non-Final Rejection — §103, §112
Sep 09, 2024
Response Filed
Oct 22, 2024
Final Rejection — §103, §112
Jan 23, 2025
Request for Continued Examination
Jan 26, 2025
Response after Non-Final Action
Apr 29, 2025
Final Rejection — §103, §112
Jul 28, 2025
Request for Continued Examination
Jul 29, 2025
Response after Non-Final Action
Sep 30, 2025
Non-Final Rejection — §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

6-7
Expected OA Rounds
62%
Grant Probability
73%
With Interview (+11.1%)
3y 5m
Median Time to Grant
High
PTA Risk
Based on 839 resolved cases by this examiner. Grant probability derived from career allow rate.

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