Prosecution Insights
Last updated: April 19, 2026
Application No. 18/148,547

ULTRA-LOW LOSS OPTICAL FIBERS FOR LONG HAUL COMMUNICATIONS

Final Rejection §103
Filed
Dec 30, 2022
Examiner
CHU, CHRIS H
Art Unit
2874
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Sterlite Technologies Limited
OA Round
6 (Final)
53%
Grant Probability
Moderate
7-8
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 21, 2025 has been fully considered and entered. Claim Objections Regarding claim 1, “mode filed diameter” is misspelled should be changed to “mode field diameter”. Appropriate correction is required. 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, 7-12, 14, 15, 18 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Nagayama et al. (US 2002/0044753 A1) in view of Bickham et al. (US 8,315,495 B2). Regarding claim 1, Nagayama discloses an optical fiber (Fig. 7), comprising: a core region (600) defined by a core relative refractive index; and a cladding region surrounding the core region (700), wherein the cladding region is down-doped with only a down-dopant for the entire radial cladding thickness (paragraph 0134); wherein the cladding region comprises an inner cladding region (701) and an outer cladding region (702), the inner cladding region is defined by an inner cladding relative refractive index, the outer cladding region is defined by an outer cladding relative refractive index, wherein the inner cladding relative refractive index is less than the outer cladding relative refractive index (Fig. 7; paragraphs 0130, 0134); and wherein the optical fiber is an ultra-low loss optical fiber (see abstract). Still regarding claim 1, Nagayama teaches the claimed invention except for specifically stating the core relative refractive index is in a range of -0.06% to +0.06% and the outer cladding relative refractive index is in a range of -0.25% to -0.28%. However, Nagayama discloses the core average relative refractive index difference is in a range of 0.01% to 0.12% (paragraph 0137) and the outer cladding average relative refractive index difference is ≥ -0.26% (paragraph 0136). As such, it would have been obvious to one having ordinary skill in the art at the time of the invention to arrive at the claimed relative refractive index ranges 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, Nagayama teaches the claimed invention except for specifically stating the core radius and mode field diameter. Bickham discloses an optical fiber comprising a core region (Figs. 1A, 1B, 3 and 15) with a radius between 6.1 µm and 6.5 µm (Table 1, Example 2), and wherein the optical fiber has a mode field diameter (MFD) of 12.5±0.5 nm wavelength (Table 2A, Example 2). Since both inventions relate to optical fibers, one having ordinary skill in the art at the time of the invention would have found it obvious to use the core radius and mode field diameter as disclosed by Bickham in the fiber of Nagayama for the purpose of increasing the effective area of the optical fiber. Further, Bickham discloses a cable cutoff wavelength of 1537 nm in Table 2A, but states that the effective fiber cutoff is lower than the theoretical cutoff and the cable cutoff wavelength is typically lower than the measured fiber cutoff due to higher levels of bending and mechanical pressure in the cable environment (column 4, lines 25-53). As such, one of ordinary skill would find it obvious to arrive at the claimed cable cutoff wavelength of 1530 nm in order to control the propagation of desired modes, and 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, the proposed combination of Nagayama and Bickham teaches the claimed invention except for specifically stating the macro-bend loss. 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 macro-bend loss in order to minimize transmission losses, and 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 claims 7-9, Nagayama discloses the inner cladding region (701) has a first fluorinated (paragraph 0134) region T1 defined by a thickness r2 – r1, which is a difference between an inner cladding radius and a core radius, the outer cladding region (702) has a second fluorinated region T2 defined by a thickness r3 - r2, which is a difference between an outer cladding radius and the inner cladding radius, and wherein the thickness of the first fluorinated region T1 is less than the thickness of the second fluorinated region T2 in Fig. 7. Regarding claims 10 and 12, the proposed combination of Nagayama and Bickham teaches the claimed invention except for specifically stating the inner and outer cladding radii. 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 inner cladding radius and outer cladding radius, 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 11, the proposed combination of Nagayama and Bickham teaches the claimed invention except for specifically stating the relative refractive index of the inner cladding. 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 relative refractive index of the inner cladding, 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 claims 14 and 15, the proposed combination of Nagayama and Bickham teaches the claimed invention except for specifically stating the attenuation. 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 attenuation in order to minimize transmission losses, and 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 18, the proposed combination of Nagayama and Bickham teaches the claimed invention except for specifically stating the macro-bend loss. 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 macro-bend loss in order to minimize transmission losses, and 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 19, the proposed combination of Nagayama and Bickham teaches the claimed invention except for specifically stating the dispersion slope. 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 dispersion slope in order to arrive at a higher capacity waveguide with a larger effective area, and 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.id crystal moleculesand specifically stating the exposure voltage greater than a Response to Arguments Applicant's arguments, filed October 21, 2025, with respect to claims have been considered but are moot in view of the new grounds of rejection above. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, 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 February 5, 2026
Read full office action

Prosecution Timeline

Dec 30, 2022
Application Filed
Oct 19, 2023
Non-Final Rejection — §103
Jan 22, 2024
Response Filed
Apr 29, 2024
Final Rejection — §103
Jul 11, 2024
Request for Continued Examination
Jul 15, 2024
Response after Non-Final Action
Oct 03, 2024
Non-Final Rejection — §103
Dec 22, 2024
Response Filed
Mar 11, 2025
Final Rejection — §103
Jun 06, 2025
Request for Continued Examination
Jun 09, 2025
Response after Non-Final Action
Jul 18, 2025
Non-Final Rejection — §103
Oct 21, 2025
Response Filed
Feb 05, 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

7-8
Expected OA Rounds
53%
Grant Probability
63%
With Interview (+10.1%)
2y 12m
Median Time to Grant
High
PTA Risk
Based on 650 resolved cases by this examiner. Grant probability derived from career allow rate.

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