Prosecution Insights
Last updated: May 04, 2026
Application No. 18/386,192

OPTICAL SWITCH FABRICS FOR HIGH PERFORMANCE COMPUTING

Final Rejection §103
Filed
Nov 01, 2023
Examiner
LI, SHI K
Art Unit
2635
Tech Center
2600 — Communications
Assignee
Chin-Tau Lea
OA Round
2 (Final)
73%
Grant Probability
Favorable
3-4
OA Rounds
7m
Est. Remaining
78%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allowance Rate
605 granted / 825 resolved
+11.3% vs TC avg
Moderate +5% lift
Without
With
+5.2%
Interview Lift
resolved cases with interview
Typical timeline
3y 1m
Avg Prosecution
19 currently pending
Career history
844
Total Applications
across all art units

Statute-Specific Performance

§101
2.0%
-38.0% vs TC avg
§103
56.8%
+16.8% vs TC avg
§102
12.5%
-27.5% vs TC avg
§112
22.7%
-17.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 825 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 . 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. Claim(s) 12-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lea (U.S. Patent Application Pub. 2018/0167702 A1) in view of Ueda et al. (Ueda et al., “Large-Scale Optical Switch Utilizing Multistage Cyclic Arrayed-Waveguide”, IEEE Photonics Journal, Vol. 9, No.1 2017). Regarding claim 12, Lea teaches in FIG. 5 a three-stage TDM switch where the first two stages have the same structure of instant claim. That is, if one considers the inputs to the last stage (AWGR 530) as the outputs of a two-stage TDM switch, the modified two-stage TDM switch has the same structure as FIG. 5A of instant specification. Ueda et al. compares in FIG. 4 a two-stage switch versus a three-stage switch and teaches in FIG. 5 a two-stage switch. One of ordinary skill in the art would have been motivated to combine the teaching of Ueda et al. with the switch of Lea because a two-stage architecture has less loss. Thus it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use a two-stage architecture, as suggested by Ueda et al., in the TDM switch of Lea. Regarding claim 13, Lea teaches in FIG. 5 a three-stage TDM switch where the last two stages have the same structure of instant claim. That is, if one considers the outputs of the first stage (the AWGR 510) as the inputs of a two-stage TDM switch, the modified two-stage TDM switch has the same structure as FIG. 6A of instant specification. Ueda et al. compares in FIG. 4 a two-stage switch versus a three-stage switch and teaches in FIG. 5 a two-stage switch. One of ordinary skill in the art would have been motivated to combine the teaching of Ueda et al. with the switch of Lea because a two-stage architecture has less loss. Thus it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use a two-stage architecture, as suggested by Ueda et al., in the TDM switch of Lea. Allowable Subject Matter Claims 9-11 are allowed. Response to Arguments Applicant's arguments filed 9 March 2026 have been fully considered but they are not persuasive. The Applicant argues that the switch by Ueda et al. is designed for circuit switching, whereas the SA switch in Claims 5-8 is intended for packet switching. Packet switching, rather than circuit switching, forms the basis of almost all datacenters and high-performance computing systems. The argument is not persuasive. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In this case, Lea teaches in FIG. 5 packet switch (see also title and abstract). The Applicant then discusses the scheduling issues and argues: If the switch's topology is reversed, the scheduler must instead find an efficient way to send packets through the AWGs first, and then through the space switches. These two scheduling tasks are fundamentally different, especially when the scheduler is implemented in a distributed fashion. Unless the topology of a switch is completely symmetric, reversing the topology of a packet switch effectively creates a different switch—one with a different scheduler, a different topology, and different performance. The argument is not persuasive. It is noted that the features upon which applicant relies (i.e., scheduling algorithms) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). 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 nonprovisional extension fee (37 CFR 1.17(a)) 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 mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to SHI K LI whose telephone number is (571)272-3031. The examiner can normally be reached M-F 6:53 a.m. -3:23 p.m. 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, David Payne can be reached at 571 272-3024. 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. skl2 April 2026 /SHI K LI/Primary Examiner, Art Unit 2635
Read full office action

Prosecution Timeline

Nov 01, 2023
Application Filed
Jul 27, 2025
Non-Final Rejection — §103
Oct 20, 2025
Response after Non-Final Action
Oct 20, 2025
Response Filed
Mar 09, 2026
Response Filed
Apr 01, 2026
Final Rejection — §103
Apr 01, 2026
Examiner Interview (Telephonic)

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
73%
Grant Probability
78%
With Interview (+5.2%)
3y 1m (~7m remaining)
Median Time to Grant
Moderate
PTA Risk
Based on 825 resolved cases by this examiner. Grant probability derived from career allowance rate.

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