Prosecution Insights
Last updated: April 19, 2026
Application No. 19/366,950

HOLLOW CORE OPTICAL FIBER AND A LASER SYSTEM

Non-Final OA §103
Filed
Oct 23, 2025
Examiner
RAHLL, JERRY T
Art Unit
2874
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Nkt Photonics A/S
OA Round
1 (Non-Final)
90%
Grant Probability
Favorable
1-2
OA Rounds
2y 1m
To Grant
98%
With Interview

Examiner Intelligence

Grants 90% — above average
90%
Career Allow Rate
1089 granted / 1215 resolved
+21.6% vs TC avg
Moderate +8% lift
Without
With
+8.4%
Interview Lift
resolved cases with interview
Fast prosecutor
2y 1m
Avg Prosecution
46 currently pending
Career history
1261
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
43.9%
+3.9% vs TC avg
§102
42.4%
+2.4% vs TC avg
§112
10.5%
-29.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1215 resolved cases

Office Action

§103
DETAILED ACTION 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 . Priority Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55 (received with parent US patent application 16/064,751). Information Disclosure Statement The information disclosure statements (IDS's) submitted comply with the provisions of 37 CFR 1.97. Accordingly, the examiner has considered the information disclosure statement; please see attached forms PTO-1449. Drawings The drawings submitted have been reviewed and determined to facilitate understanding of the invention. The drawings are accepted as submitted. 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 (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. 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. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1-9 and 12-20 are rejected under 35 U.S.C. 103 as being unpatentable over US Patent Application Publication 2017/0097464 to Challener et al. (hereinafter “US1”). Regarding Claim 1, US1 describes a hollow core photonic crystal fiber (PCF) (102, see Fig 2) comprising an outer cladding region (136) and seven hollow tubes (134) surrounded by the outer cladding region, each of the hollow tubes having an average outer tube diameter d2 and an average inner tube diameter d1 (shown in Fig 2), wherein each of the hollow tubes is fused to the outer cladding region to form a ring defining an inner cladding region (132) and a hollow core region (118) surrounded by the inner cladding region (see Fig 2), wherein the hollow tubes are not touching each other (see Fig 2 and [0043], wherein the hollow tubes are free of a nested sub-tube (see Fig 2), and wherein the hollow core region has a core diameter D of from about 10 μm to about 100 μm (see [0038], [0043]). US1 does not describe wherein d1/d2 is equal to or larger than about 0.8. US1 is silent as to d1 and d2 of the described hollow tubes. Before the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to form the hollow tubes of US1 such that d1/d2 is equal to or larger than about 0.8, since such a modification would have involved a mere change in the size of a component. A change in size is generally recognized as being within the level of ordinary skill in the art. In re Rose, 105 USPQ 237 (CCPA 1955). Regarding Claims 2-6 and 8, US1 does not describe the hollow core PCF structures having the claimed dimensions. Before the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to form hollow core PCT of US1 having the claimed dimensions, since such a modification would have involved a mere change in the size of a component. A change in size is generally recognized as being within the level of ordinary skill in the art. In re Rose, 105 USPQ 237 (CCPA 1955). Regarding Claim 7, US1 describes the hollow core region and the hollow tubes independently of each other (no physical passage allows for a connection between the internal spaces of the hollow region and hollow tubes, see Fig 2) comprising air or a mixture thereof (introduced via port holes 122, see [0002], [0048]). US1 is silent as to the interior of the hollow tubes. However, if no steps are undertaken during manufacturing (and no such steps are described by US1), air would inherently be introduced to the interior of the hollow tubes. Regarding Claim 9, US1 describes the hollow tubes comprising a solid glass material (see [0029]). Regarding Claims 12-14, US1 does not describe the hollow core region and/or one or more of the hollow tubes as evacuated from gas. It is common in hollow fiber structures to evacuate at a pressure of about .01 mbar or less such areas in order to ensure a uniform optical performance throughout the length of the fiber. Therefore, before the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to form the hollow tubes of US1 as evacuated as claimed. Regarding Claim 15, US1 describes a laser system for delivering laser light to a user apparatus (see Fig 1), the laser system comprising a laser light source (106) and a fiber delivery cable (102) for delivering light from the laser light source to the user apparatus (see [0036]-[0037]), wherein the fiber delivery cable comprises a hollow core PCF according to claim 1 (see Fig 2 and discussion above herein). Regarding Claims 16-17, US1 does not describe the hollow core PCF structures having the claimed dimensions. Before the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to form hollow core PCT of US1 having the claimed dimensions, since such a modification would have involved a mere change in the size of a component. A change in size is generally recognized as being within the level of ordinary skill in the art. In re Rose, 105 USPQ 237 (CCPA 1955). Regarding Claims 18-19, US1 does not describe the exact nature of the laser light source. However, laser light sources having the claimed properties are well-known in the art. Before the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use such laser light sources for the source of US1. The motivation for doing so would have been to make a simple substitution of one known element for another to obtain predictable results. Regarding Claim 20, US1 does not describe the specific method of optically and physically connecting the light source and cable. The claimed connection configurations are well-known in the art. Before the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use configurations to connect the light source and cable of US1. The motivation for doing so would have been to make a simple substitution of one known element for another to obtain predictable results. Allowable Subject Matter Claims 10-11 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 10 describes at least one of the hollow tubes has a different wall thickness than at least one other of the hollow tubes. Claim 11 describes three of the hollow tubes have a first wall thickness and four of the hollow tubes have second wall thickness, wherein the first wall thickness is different from the second wall thickness. These limitations represent subject matter not described or reasonably suggested, in conjunction with the further limitations of the present claims, by the prior art of record. Conclusion The prior art cited in the attached form PTO-892 are made of record and considered pertinent to applicant's disclosure. The cited prior art describe hollow core PCFs with cladding structures. Any inquiry concerning this communication or earlier communications from the examiner should be directed to JERRY RAHLL whose telephone number is (571)272-2356. The examiner can normally be reached M-F 9:00am-5:00pm. 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, Uyen-Chau Le can be reached at 571-272-2397. 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. /JERRY RAHLL/Primary Examiner, Art Unit 2874
Read full office action

Prosecution Timeline

Oct 23, 2025
Application Filed
Feb 17, 2026
Non-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

1-2
Expected OA Rounds
90%
Grant Probability
98%
With Interview (+8.4%)
2y 1m
Median Time to Grant
Low
PTA Risk
Based on 1215 resolved cases by this examiner. Grant probability derived from career allow rate.

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