Prosecution Insights
Last updated: April 19, 2026
Application No. 18/250,750

FERRULE FOR OPTICAL CONNECTOR AND METHOD OF MANUFACTURING OPTICAL CONNECTOR

Final Rejection §103
Filed
Apr 27, 2023
Examiner
CHU, CHRIS H
Art Unit
2874
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Fujikura Ltd.
OA Round
2 (Final)
53%
Grant Probability
Moderate
3-4
OA Rounds
2y 12m
To Grant
63%
With Interview

Examiner Intelligence

Grants 53% of resolved cases
53%
Career Allow Rate
345 granted / 650 resolved
-14.9% vs TC avg
Moderate +10% lift
Without
With
+10.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 12m
Avg Prosecution
44 currently pending
Career history
694
Total Applications
across all art units

Statute-Specific Performance

§101
0.3%
-39.7% vs TC avg
§103
74.2%
+34.2% vs TC avg
§102
20.0%
-20.0% vs TC avg
§112
1.8%
-38.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 650 resolved cases

Office Action

§103
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 . DETAILED ACTION Response to Amendment Applicant’s Amendment filed on October 7, 2025 has been fully considered and entered. Claim Rejections - 35 USC § 103 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 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. 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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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. Claims 1 and 3 are rejected under 35 U.S.C. 103(a) as being unpatentable over Oka et al. (JP S52141241 from Applicant’s Information Disclosure Statement). Regarding claim 1, Oka discloses a ferrule (2 in Fig. 1) for an optical connector (see Fig. 2, ferrule is part of a connector), the ferrule comprising a main body part formed with a fiber hole (3) configured to accommodate insertion of an optical fiber (1), wherein an inner diameter dh of the fiber hole is smaller than an outer diameter df of a cladding of the optical fiber (paragraph 0002), resulting in a ratio of less than 1.0. Still regarding claim 1, Oka teaches the claimed invention except for specifically stating the ratio of the inner diameter dh of the fiber hole to the outer diameter df of the cladding of the optical fiber. However, it would have been obvious to one having ordinary skill in the art at the time of the invention to arrive at the claimed ratio, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233. Still regarding claim 1, Oka further discloses the ferrule configured to accommodate the optical fiber due to expanding when heated in paragraph 0002. Oka teaches the claimed invention except for specifically stating the claimed coefficient of linear expansion. However, one of ordinary skill in the art before the effective filing date of the claimed invention would have found it obvious to arrive at the claimed range, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233. Regarding claim 3, Oka teaches the claimed invention except for the material of the main body part. However, it would have been obvious to one having ordinary skill in the art at the time of the invention to form the main body part from polyether ether ketone (PEEK), since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416. Further, it would have been obvious to one having ordinary skill in the art at the time of the invention to arrive at the claimed ratio, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233. Response to Arguments Applicant's arguments, see pages 4-7, with respect to claims have been considered but are not persuasive. On pages 4-6, Applicant states that Oka is silent regarding any ratio that compares a diameter of the hole in the ferrule to the outer diameter of the cladding of the optical fiber. Specifically, Applicant asserts that “Oka discloses that the cladding 4 is stripped from the optical fiber.” However, Oka only discloses the coating 4 is stripped, not the cladding. See paragraph 0002, in which Oka states “the coating 4 on the tip of the [light pipe 1] is peeled off.” Thus, contrary to Applicant’s assertion, Oka does not disclose the cladding being stripped from the optical fiber, only the coating. It is well known in the art of optical fibers that the coating is a different layer than the cladding. Most fibers contain an outer protective jacket as well as various coating layers in addition to a fiber core and cladding. The cladding has a lower refractive index than a light guiding core and is essential for allowing the light within the core to propagate by total internal reflection. For example, U.S. Pat No. 6,074,101 to Bloom (in the Notice of References Cited on July 9, 2025 and therefore on the record) shows an optical fiber (Fig. 1) comprising an outer protective jacket (4), a Kevlar yarn strength member (6), and a polymer tight buffer coating (8) surrounding an optical fiber 10. Column 4, lines 47-51 describe the fiber in Fig. 1 “properly stripped and ready for attachment [to] a connector.” As seen in Fig. 1, the jacket, strength member and coating have been stripped, leaving the “bare” optical fiber (containing a core and cladding). Thus, a fiber having a coating removed does not equate to a fiber having the cladding removed. Further, even assuming arguendo the coating is somehow equated to the cladding, Oka discloses a ferrule which receives the coated fiber 4 as well as the stripped fiber 3. The ferrule comprises of Oka comprises two different hole portions - a smaller hole for receiving the stripped fiber, but also a larger hole at the flange for receiving the coated fiber. Claim 1 as currently constructed merely requires a ferrule with “a fiber hole” for insertion of an optical fiber. Thus, the larger hole in the flange which into which the coated fiber is inserted and received would still read on the claim. When Oka’s ferrule is heated, this larger hole is expanded to allow for insertion of the coated fiber and when cooled, contracts to fix the coated fiber. On pages 6-7, Applicant alleges that Oka fails to disclose the coefficient of linear expansion is a result-effective variable for securing the optical fiber. However, contrary to Applicant’s assertion, Oka specifically states in paragraph 0002 that the securing of the optical fiber is dependent on the “the coefficient of linear expansion of the fiber holder 2, the coefficient of expansion T of the optical fiber 1, the normal temperature and the temperature when heated.” The abstract also describes that the optical fiber is fixed to the holder by thermal contraction and/or thermal expansion, providing further support that the coefficient of linear expansion is the critical variable. Thus, Oka clearly and explicitly recognizes the coefficient of linear expansion of the fiber holder as a variable that affects a particular outcome or result. This recognition would lead one of ordinary skill to adjust or optimize said variable to achieve a desired result by routine experimentation. For the reasons stated above, the prima facie rejection is maintained. Conclusion THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHRIS H CHU whose telephone number is (571)272-8655. The examiner can normally be reached on Mon-Fri 9AM-5PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Uyen-Chau Le can be reached on 571-272-239797. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Any inquiry of a general or clerical nature should be directed to the Technology Center 2800 receptionist at telephone number (571) 272-1562. Chris H. Chu /CHRIS H CHU/Primary Examiner, Art Unit 2874 January 14, 2026
Read full office action

Prosecution Timeline

Apr 27, 2023
Application Filed
Jul 07, 2025
Non-Final Rejection — §103
Oct 07, 2025
Response Filed
Jan 15, 2026
Final Rejection — §103 (current)

Precedent Cases

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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
53%
Grant Probability
63%
With Interview (+10.1%)
2y 12m
Median Time to Grant
Moderate
PTA Risk
Based on 650 resolved cases by this examiner. Grant probability derived from career allow rate.

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