Prosecution Insights
Last updated: May 04, 2026
Application No. 18/337,713

DIFFERENTIAL FREQUENCY GENERATION

Non-Final OA §102§103
Filed
Jun 20, 2023
Priority
Jan 12, 2023 — provisional 63/438,750
Examiner
HARVEY, MINSUN OH
Art Unit
2828
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
Government Of The United States AS Represented By The Secretary Of The Air Force
OA Round
1 (Non-Final)
75%
Grant Probability
Favorable
1-2
OA Rounds
6m
Est. Remaining
99%
With Interview

Examiner Intelligence

Grants 75% — above average
75%
Career Allowance Rate
9 granted / 12 resolved
+7.0% vs TC avg
Strong +27% interview lift
Without
With
+27.3%
Interview Lift
resolved cases with interview
Typical timeline
3y 5m
Avg Prosecution
1 currently pending
Career history
13
Total Applications
across all art units

Statute-Specific Performance

§103
54.4%
+14.4% vs TC avg
§102
26.3%
-13.7% vs TC avg
§112
19.3%
-20.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 12 resolved cases

Office Action

§102 §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 Acknowledgment is made of applicant’s claim for domestic benefit through application 63/483750. Information Disclosure Statement The information disclosure statement (IDS) submitted on June 20, 2023 was filed in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement has been considered by the examiner. Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claims 10, 13 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Keyser et al. US 20210013690. Regarding Claim 10, Keyser teaches A difference frequency generator (Fig. 1) comprising: a light source (Fig. 1, 110) in communication with a hollow core fiber (Fig. 1, 104 Paragraph 0031 “In one or more embodiments, the optical fiber 104 of the fiber assembly 106 is has a hollow core that is filled with a fluid comprising one or more of a gas and a liquid.”), the hollow fiber being filled with one of a liquid with Λ from 100 µm to 1000 µm, and σ from 0.1 µm to 10 µm, or a gas with Λ from 1000 µm to 10000 µm, and σ from 1.0 µm to 10 µm; (Fig. 5 shows the poling period in microns for Xenon and Fig. 6 shows the poling period in microns for CS2. Both are within the given Λ ranges. In addition both Figs. Show the poling periods on a sliding scale giving them the tolerance σ) two spaced apart electrodes configured to enable second order wave mixing the liquid or gas inside the hollow fiber, (Paragraph 0029 “The generally-known approach only achieved a conversion efficiency of about 0.1% and only focused on second harmonic generation. By using periodic electrodes of opposite polarity opposed to one another, our OPA is anticipated to have a conversion efficiency of approximately 30% based on modeling.”) and having an electrode period of 0.1 - 10.0% of Λ. (Fig. 6) Regarding Claim 13, Keyser teaches a hollow fiber filled with at least two mixed liquids not having mutually overlapping Raman lines. (Paragraph 0031 “In one or more embodiments, the optical fiber 104 of the fiber assembly 106 is has a hollow core that is filled with a fluid comprising one or more of a gas and a liquid.” It is inherent to every material that it will have its own Raman spectrum and Raman lines. Since no two materials have the same Raman lines there will not be complete overlapping Raman lines.) 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. The factual inquiries 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, 5, 12 are rejected as being unpatentable over 35 U.S.C. 103 over Keyser in view of Trevor L. Courtney et al. “Optical parametric generation in liquid- and gas-filed hollow core fibers” Proc. SPIE 11405, Optical Waveguide and Laser Sensors, 114050I (23 April 2020) (Found in IDS) Regarding Claim 1, Keyser teaches A liquid filled quasi-phase matched optical parametric amplification fiber laser (Fig. 2a) comprising: a light source in optical communication with a light transmitting fiber having a cladding (See annotated Fig. 2A below) and a liquid filled core therein, the liquid being a liquid adapted for OPA, (Paragraph 0033 “FIG. 2A depicts a linear fiber assembly 206a that includes gas/liquid-filled HCPCF 204 with periodic electrode structure or set 202a-202b enabling QPM OPA laser generation.” Paragraph 0037 “Liquid could be used instead of gas. FIG. 5 depicts a graphical plot 500 of electrode poling period versus signal wavelength for different xenon (Xe) pressures and HCPCF diameters. FIG. 6 depicts a graphical plot 600 for a liquid-filled HCPCF that uses carbon disulfide (CS2).” Carbon disulfide is a nonpolar molecule in the absence of an electric field, however in the presence of an electric field a nonpolar molecule becomes a polar molecule. Fig. 2A shows a bunch of electrodes around the device which creates an electric field which makes carbon disulfide a polar liquid while in the fiber. See pertinent art #1 below) Keyser does not teach the fiber having a Λ/D value ranging from 2.3 to 666.7. However, Trevor teaches the fiber having a Λ/D value ranging from 2.3 to 666.7. (Fig. 2(b) having a Λ value of between 750 microns and 1000 microns for CS2. Page 4 Paragraph 8 states a HC-PCF radius of 17.5 microns you get a Λ/D of 750/17.5 = 42.86 which is within the range. ) It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Λ/D as taught by Keyser because changing the Λ/D would optimize the amount of phase matching that is occurring (Trevor Page 4 Section 2.2 Quasi-phase-matching) (MPEP 2144.05 II). PNG media_image1.png 357 689 media_image1.png Greyscale Regarding Claim 5, Keyser teaches the liquid has a dielectric constant ranging from 1 to 40. (Carbon disulfide has a dielectric constant of 2.641 See Pertinent art #2) Regarding Claim 12, Keyser does not teach the fiber having a Λ/D value ranging from 3 to 500 and D is the separation distance between electrodes in microns. However, Trevor teaches the fiber having a Λ/D value ranging from 3 to 500 and D is the separation distance between electrodes in mircons. (Fig. 2(b) having a Λ value of between 750 microns and 1000 microns for CS2. Page 4 Paragraph 8 states a HC-PCF radius of 17.5 microns you get a Λ/D of 750/17.5 = 42.86 which is within the range. ) It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Λ/D as taught by Keyser because changing the Λ/D would optimize the amount of phase matching that is occurring (Trevor Page 4 Section 2.2 Quasi-phase-matching) (why there is optimization) (MPEP 2144.05 II). Claims 7 are rejected as being unpatentable over 35 U.S.C. 103 over Keyser and Trevor in view of Levatter US 4927231. Regarding Claim 7, Keyser in combination with Trevor does not teaches ncore > ncladding. However, Levatter teaches ncore > ncladding (Col. 2 Lines 3-7 “The liquid light guide 2 is preferably a flexible hollow tube 3 filled with a liquid (such as high purity water) which is substantially transparent to the wavelength of laser energy employed, and which has a higher index of refraction than the surrounding tube 3.”) It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the index of refractions of the core and cladding as taught by Keyser by having the core have a greater index of refraction than the cladding as disclosed by Levatter. One of ordinary skill in the art would have been motivated to make this modification in order to keep light within the core more easily due to total internal reflection. Claim 11 is rejected as being unpatentable over 35 U.S.C. 103 over Keyser. Regarding Claim 11, Keyser does not teach the generator satisfies the equation deff,QPM DFG = k*χ(2)/2 However, It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the generator as taught by Keyser because modifying the generator to satisfy the equation deff,QPM DFG = k*χ(2)/2 would optimize phase matching (Keyser Paragraph 0009) (MPEP 2144.05 II). Allowable Subject Matter Claims 2-4, 6, 8-9 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. Regarding Claim 2, Keyser does not teach the liquid further comprises Zwitterionic molecules. Regarding Claim 3, Keyser does not teach the liquid further comprises imidazolium ionic liquids having dipole moments from 12 D to 14 D. Claim 4 is dependent from Claim 3. Regarding Claim 6, Keyser does not teach the liquid comprises from 80 w/% to 95 w/% bromotrichloromethane and from 5 w% to 15 w/% perfluorohexane. Regarding Claim 8, Keyser does not teaches ncore < ncladding. Regarding Claim 9, Keyser does not teach the liquid further comprises charge transfer molecules having a bond length alternation from -0.045 to +0.045 whereby the liquid is configured for OPA and OPG. Claim 14-20 are allowed. Regarding Claim 14, Keyser teaches A method of making a liquid filled quasi-phase matched optical parametric amplification fiber laser comprising the steps of: selecting a transmissive solvent; (Fig. 6 shows CS2 is selected); and disposing the liquid in a light transmitting fiber in optical communication with a light source. (Paragraph 0031 “In one or more embodiments, the optical fiber 104 of the fiber assembly 106 is has a hollow core that is filled with a fluid comprising one or more of a gas and a liquid.”) Keyser does not teach selecting a nonlinear liquid charge transfer molecule having a uB ranging from 2 to E-48 esu to 2 E-40 esu and combining the nonlinerar liquid charge transfer molecule and the NIR transmissive solvent to yield a liquid having a dielectric constant of 1.5 to 7.5 to thereby provide a QPM OPA/G gain/SRS gain ratio greater than 1; Claims 15-20 are dependent on Claim 14. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. https://phys.libretexts.org/Courses/Kettering_University/Electricity_and_Magnetism_with_Applications_to_Amateur_Radio_and_Wireless_Technology/07%3A_Capacitance/7.06%3A_Molecular_Model_of_a_Dielectric (Page 1 Paragraph 1 “Nonpolar molecules can become polar in the presence of an external electric field, which is called induced polarization”) https://en.wikipedia.org/wiki/Carbon_disulfide_(data_page)#:~:text=log10%20of%20Carbon%20disulfide,Uses%20formula:%20obtained%20from%20CHERIC Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEPHEN SUTTON KOTTER whose telephone number is (571)270-1859. The examiner can normally be reached Monday - Friday 8:00-5:00. 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, MinSun Harvey can be reached at 571-272-1835. 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. /STEPHEN SUTTON KOTTER/Examiner, Art Unit 2828 /MINSUN O HARVEY/Supervisory Patent Examiner, Art Unit 2828
Read full office action

Prosecution Timeline

Jun 20, 2023
Application Filed
Apr 09, 2026
Non-Final Rejection — §102, §103 (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

1-2
Expected OA Rounds
75%
Grant Probability
99%
With Interview (+27.3%)
3y 5m (~6m remaining)
Median Time to Grant
Low
PTA Risk
Based on 12 resolved cases by this examiner. Grant probability derived from career allowance rate.

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