DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the America Invents Act (AIA ).
Response and Claim Status
The instant Office action is responsive to the response received January 6, 2026 and January 24, 2026 (the “Response”).
In response to the Response, the previous (1) objections to the drawings under 37 C.F.R. § 1.84; (2) objection to the Abstract under 37 C.F.R. § 1.72(b); (3) objection to claims 3–5 under 37 C.F.R. § 1.71(a); (4) rejection of claims 1–4, 6, 7, 10, and 11 on the ground of nonstatutory double patenting; (5) rejection of claims 1–11 under 35 U.S.C. § 112(b)
are WITHDRAWN.
Claims 1–9 and 11 are currently pending.
Means-plus-Function Language
The following is a quotation of 35 U.S.C. § 112(f):
ELEMENT IN CLAIM FOR A COMBINATION.—An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof
The instant application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under § 112(f) because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitations are:
“system synchronization unit” (claim 1, line 2; claim 10, line 3);
“narrow-pulse generating unit” (claim 3, line 3); and
“synchronized light detection unit” (claim 6, line 3).
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the Specification as performing the claimed function, and equivalents thereof.
System Synchronization Unit
With respect to the “system synchronization unit” (claim 1, line 2; claim 10, line 3), Applicants direct attention to page 6 of the Specification and Figure 4. See Response 9 (citing Figures 4A and 4B, and paragraphs 35 and 37 of Chen et al. (US 2024/0372630 A1)). Page 6 of the Specification recites
Referring to FIG. 4A, the system synchronization unit 101 included in the gating apparatus for the single-photon detector according to an illustrative example of the present disclosure may include a synchronized light detection unit 106, and the synchronized light detection unit 106 may be configured to convert received synchronized light of the quantum communication system (i.e., synchronized light that is synchronously emitted with optical pulses in an encoded signal) into a synchronized electrical signal, to acquire the clock 1010 of the quantum communication system.
The Examiner finds one skilled in the art would reasonably be expected to draw a photodiode converts received synchronized light into a synchronized electrical signal to acquire a clock. See MPEP § 2181(II)(A)(reciting “The disclosure of the structure (or material or acts) may be implicit or inherent in the specification if it would have been clear to those skilled in the art what structure (or material or acts) corresponds to the means- (or step-) plus-function claim limitation.”); see also id. § 2144.01. Thus, the Specification implicitly covers the corresponding structure for performing the claimed function of the “system synchronization unit” (claim 1, line 2; claim 10, line 3).
Synchronized Light Detection Unit
As discussed above, the Examiner finds one skilled in the art would reasonably be expected to draw a photodiode converts received synchronized light into a synchronized electrical signal to acquire a clock. Thus, the Specification implicitly covers the corresponding structure for performing the claimed function of the “synchronized light detection unit” (claim 6, line 3).
Narrow-Pulse Generating Unit
With respect to the “narrow-pulse generating unit” (claim 3, line 3), Applicants direct attention to page 5 of the Specification and Figure 3. See Response 10 (citing Figures 3A and 3B, and paragraph 30 of Chen et al. (US 2024/0372630 A1)).
The Examiner finds one skilled in the art would reasonably be expected to draw a gate driving circuit to narrow a pulse width of gating signals in a periodic gating signal sequence. Thus, the Specification implicitly covers the corresponding structure for performing the claimed function of the “narrow-pulse generating unit” (claim 3, line 3).
If Applicants do not intend to have the claim limitations treated under § 112(f), Applicants may amend the claims so that they will clearly not invoke § 112(f), or present a sufficient showing that the claims recite sufficient structure, material, or acts for performing the claimed function to preclude application of § 112(f).
For more information, see MPEP § 2173 et seq. and Supplementary Examination Guidelines for Determining Compliance With 35 U.S.C. 112 and for Treatment of Related Issues in Patent Applications, 76 FR 7162, 7167 (Feb. 9, 2011) (available at https://www.govinfo.gov/content/pkg/FR-2011-02-09/pdf/2011-2841.pdf).
Claim Rejections – 35 U.S.C. § 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.
Claims 1–4, 6, and 11 are rejected under 35 U.S.C. § 103 as being obvious over Chen et al. (CN 111504482 A; filed Apr. 29, 2020; published Aug. 7, 2020)(Chen ‘482)1 in view of Chen et al. (CN 110752882 A; filed July 24, 2018; published Feb. 4, 2020)(Chen ‘882)2.
Response to Arguments
Applicants argue “Chen ‘482 does not teach or suggest using the optical path difference between the long arm and the short arm of the unequal-arm interferometer set the interval between gating signals in a periodic gating signal sequence.” Response 11.
The Examiner is unpersuaded of error because Applicants’ argument is non-responsive to the rejection, which does not rely on Chen ‘482 to teach using an optical path difference between a long arm and a short arm of an unequal-arm interferometer to set an interval between gating signals in a periodic gating signal sequence.
Next, Applicants argue “Chen ‘882 does not teach or suggest using this optical path difference to set the interval between gating signals in a periodic gating signal sequence for a single-photon detector.” Response 11.
The Examiner is unpersuaded of error. The Examiner directs attention to the below Examiner’s marked-up copy of Chen ‘482’s Figure 10.
Next, Applicants argue
Chen ‘882 does not provide any technical teaching or motivation to apply the optical path difference between the long arm and the short arm of the unequal-arm interferometer to the gating signal interval of the single-photon detector. The reasons are as follows.
First, the technical fields and problems addressed are entirely different. Chen ‘882 relates to a phase encoding system with a low bit error rate and a receiving end thereof, aiming to solve the problem of polarization disturbance at the decoding end of the interferometer caused by arm differences, thereby improving interference contrast and reducing the bit error rate (See, paras.[0001]-[0010]). Its technical solution consistently revolves around the internal optical path design of the interferometer. It does not involve the gating timing of single-photon detectors, nor does it mention detector performance indicators such as dark counts or afterpulses.
Second, the purpose and function of using the optical path difference are fundamentally different from those in the amended claim 1 of the present application. In Chen ‘882, the optical path difference between the long arm and short arm is set as the time interval between the preceding and subsequent optical pulses. The purpose is to enable these pulses to meet and interfere at the beam splitter (See, paras.[0031]-[0036], claim 1). This optical path difference is solely an internal geometric parameter of the interferometer, used to control the pulse propagation path, and is not employed as a timing parameter for external circuits. The entire document (including Claims, Specification, and Drawings) never mentions using this optical path difference to set the gating signal interval for a single-photon detector. Furthermore, relevant terms such as “gate”, “gating signal”, “gate duration”, “detector timing”, “dark count”, or “after-pulse” are absent.
Response 12.
The Examiner is unpersuaded of error. The scope of analogous prior art falls under at least one of two separate tests: whether the reference’s art is from the same field of endeavor as the invention, regardless of the problem addressed and, (2) if the reference is not within the field of the inventor’s endeavor, whether the reference still is reasonably pertinent to the particular problem with which the inventor is involved. See In re Kahn, 441 F.3d 977, 986-87 (Fed. Cir. 2006).
The claimed subject matter is directed to “a gating apparatus for a single-photon detector.” Spec. 1; claim 1, line 1. Chen ‘882 is directed to a gating apparatus (fig. 3 including item 3) for a single-photon detector (“the detection module 3 may include a single photon detector” at p. 4). Based on this similarity, the Examiner finds Chen ‘882 and the claimed subject matter are within the same field of endeavor. See Kahn, 441 F .3d at 986-87.
Even assuming Chen ‘882 and the claimed subject matter are not within the same field of endeavor (but they are within the same field of endeavor), the Specification discusses the problem to be solved by the invention––”In order to solve the described problem, the present disclosure provides a gating apparatus for a single-photon detector and a quantum communication device.” Spec. p. 1. Chen ‘882 is directed to “communication field, specifically relates to a phase encoding system can provide high contrast and low error code rate and the receiving end, which is particularly suitable for the distribution of quantum keys.” Chen ‘882 p. 1. The phase encoding system of Chen ‘882 is illustrated in Figure 3 of Chen ‘882. See id. at p. 3 (reciting “FIG. 3 shows a phase encoding system”). Figure 3 of Chen ‘882 teaches a gating apparatus (fig. 3) for a single-photon detector (“the detection module 3 may include a single photon detector” at p. 4) and a quantum communication device (fig. 3, items 1, 4, 21). The Examiner finds a reference that teaches a gating apparatus for a single-photon detector and a quantum communication device would have logically commended itself to a skilled person faced with the problems in the field of providing a gating apparatus for a single-photon detector and a quantum communication device. See In re Klein, 647 F.3d 1343, 1348 (Fed. Cir. 2011); see also Kahn, 441 F .3d at 986-87.
Next, Applicants argue
[t]hird, the technical effect achieved is not reasonably expectable. The amended claim 1 of the present application achieves the technical effects of simultaneously reducing dark counts and afterpulse counts, and significantly reducing the gating duty cycle, by precisely setting the interval between gating signals in the gating signal sequence to the optical path difference of the unequal- arm interferometer. This ensures the single-photon detector opens only during the time windows where valid optical pulses are likely to arrive (See Figs.6A-6B, Fig. 7, paras.[0046]-[0048]). This technical effect is neither disclosed in Chen ‘882 nor can it be reasonably derived from its disclosed technical solution.
Response 13.
The Examiner is unpersuaded of error because Applicants’ argument is not commensurate with the scope of claim 1, which does not recite simultaneously reducing dark counts and afterpulse counts, and significantly reducing a gating duty cycle, by precisely setting the interval between gating signals in a gating signal sequence to an optical path difference of an unequal-arm interferometer. See In re Self, 671 F.2d 1344, 1348 (CCPA 1982) (limitations not appearing in the claims cannot be relied upon for patentability).
Finally, Applicants argue
it would not been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to apply the teaching of Chen ‘882 (i.e., the optical path difference) to the gating interval in Chen ‘482 to arrive at the technical solution of the amended claim 1 of the present application. The reasons are as follows.
First, regarding technical motivation, Chen ‘882 does not indicate that the optical path difference can be used to reduce dark counts or afterpulses in a single-photon detector. [O]ne [sic] of ordinary skill in the art cannot glean any motivational teaching in this regard from Chen ‘882.
Second, regarding technical effect, the present application achieves a synergistic effect (reducing dark counts, afterpulses, and the gating duty cycle) through the specific gating interval setting. This effect is neither disclosed in Chen ‘882 nor can it be reasonably expected based on its teachings concerning interferometer.
Response 13.
The Examiner is unpersuaded of error. At the outset, Applicants’ argument is not commensurate with the scope of claim 1, which does not recite reducing dark counts, afterpulses, and a gating duty cycle (a synergistic effect) in a single-photon detector by using a optical path difference. See Self, 671 F.2d at 1348.
The Examiner concludes it would have been obvious to modify the
teachings of Chen ‘482 with Chen ‘88 so that “the structure . . . is simpler and better environment is stable, at the same time.” Chen ‘882 p. 3. It is well settled that
an implicit motivation to combine exists not only when a suggestion may be gleaned from the prior art as a whole, but when the “improvement” is technology-independent and the combination of references results in a product or process that is more desirable, for example because it is stronger, cheaper, cleaner, faster, lighter, smaller, more durable, or more efficient.
DyStar Textilfarben GmbH & Co. Deutschland KG v. C.H. Patrick Co., 464
F.3d 1356, 1368 (Fed. Cir. 2006). Thus, to the extent that the Examiner’s rationale to combine the references results in a more efficient product or process, such an enhancement flows from the references’ teachings and is an adequate motivation to combine the references.
The Rejection
Regarding claim 1, while Chen ‘482 teaches a gating apparatus (figs. 7, 9) for a single-photon detector (figs. 7, 9, item 101), comprising:
a system synchronization unit (Chen ‘482 at least suggests figs. 7, 9 including software), configured to acquire a clock (fig. 8, item 401; fig. 10, item 403; see below Examiner’s marked-up copy of Chen ‘482’s Figure 10) of a quantum communication system (figs. 7, 9); and
a programmable controller (Chen ‘482 at least suggests figs. 7, 9 including a processor), configured to generate a periodic gating signal sequence (fig. 8, item 4013; fig. 10, item 4033; see below Examiner’s marked-up copy of Chen ‘482’s Figure 10) that are synchronized (fig. 8 illustrates item 401 synchronized with item 4013; fig. 10 illustrates item 403 synchronized with item 4033) with the clock of the quantum communication system,
wherein each gating signal sequence (see below Examiner’s marked-up copy of Chen ‘482’s Figure 10) in the periodic gate signal sequence includes at least two gate signals (see below Examiner’s marked-up copy of Chen ‘482’s Figure 10), and the gating signals in the each gating signal sequence are spaced apart from each other by a predetermined duration (fig. 8 illustrates the gating signals of item 4013 are spaced apart from each other by an equal predetermined duration; “gating signal 4033 as shown in the first row of Fig. 2b has the same period T as the detector gating signal 4013” at p. 5),
so that the single-photon detector in the quantum communication system turns on gating of the single-photon detector with regard to a received optical pulse (“when the system configuration single photon detector 101 receives detector gating signal 4013, the gating of the single photon detector 101 is opened, at this time” at p. 5; “the system configuration single photon detector 101 receives the detector gating signal 4013 shown in FIG. 8 fourth row, the gating of the single photon detector 101 is opened, at this time” at p. 8),
Chen ‘482 does not teach wherein the predetermined duration is an optical path difference between a long arm and a short arm of an unequal-arm interferometer that is used for performing phase encoding in the quantum communication system.
Chen ‘882 teaches an optical path difference between a long arm and a short arm (“the long arm 22 and the short arm of the optical path difference 23 is set to be identical with the time interval between the two optical pulses” at p. 3) of an unequal-arm interferometer (“unequal-arm interferometer 2” at p. 3) that is used for performing phase encoding in a quantum communication system (“phase encoding system . . . particularly suitable for the distribution of quantum keys” at p. 1; “FIG. 3 shows a phase encoding system” at p. 4) (intended use in italics).
It would have been obvious to one of ordinary skill in the art before the filing date of the invention for Chen ‘482’s predetermined duration to be an path difference between a long arm and a short arm of an unequal-arm interferometer that is used for performing phase encoding in the quantum communication system as taught by Chen ‘882 so that “the structure . . . is simpler and better environment is stable, at the same time.” Chen ‘882 p. 3.
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Examiner’s marked-up copy of Chen ‘482’s Figure 10
Regarding claim 2, Chen ‘482 does not teach wherein the quantum communication system is based on time-phase encoding or based on phase encoding.
Chen ‘882 teaches a quantum communication system (“phase encoding system . . . particularly suitable for the distribution of quantum keys” at p. 1) based on time-phase encoding or based on phase encoding (“phase encoding system” at p. 1).
It would have been obvious to one of ordinary skill in the art before the filing date of the invention for Chen ‘482’s quantum communication system to be based on time-phase encoding or based on phase encoding as taught by Chen ‘882 so that “the structure . . . is simpler and better environment is stable, at the same time.” Chen ‘882 p. 3.
Regarding claim 3, while Chen ‘482 teaches wherein the gating apparatus further comprises: the pulse width (fig. 8, item 4013; fig. 10, item 4033 include an inherent pulse width) of gating signals in the periodic gating signal sequence (fig. 8, item 4013; fig. 10, item 4033),
Chen ‘482 does not teach a narrow-pulse generating unit, configured to narrow a pulse width of the gating signals.
Chen ‘482 teaches a narrow-pulse generating unit (Chen ‘482 at least suggests figs. 7, 9 including software), configured to narrow a pulse width of the signals (“optical fibre channel to realize multi-node synchronous information transmission, multiplexing, the synchronous light can be a low frequency signal, a narrow pulse whose duty ratio is less than or equal to 1 %, and further a narrow pulse with a duty ratio less than or equal to 1 %” at p. 6).
It would have been obvious to one of ordinary skill in the art before the filing date of the invention for the inherent pulse width of Chen ‘482’s gating signals in the periodic gating signal sequence to be narrowed by a narrow-pulse generating unit as taught by Chen ‘482 to “improve[[s]] the detection efficiency of the single photon detector.” Chen ‘482 p. 3.
Regarding claim 4, while Chen ‘482 teaches wherein the programmable controller is configured to generate a periodic gating signal sequence (fig. 8, item 4013; fig. 10, item 4033),
Chen ‘482 does not teach two identical periodic gating signal sequences.
It would have been prima facie obvious to one of ordinary skill in the art before the filing date of the invention for the Chen ‘482 to duplicate the periodic gating signal sequence to produce two identical periodic gating signal sequences since “mere duplication of parts has no patentable significance unless a new and unexpected result is produced.” MPEP § 2144.04(VI)(B) (describing In re Harza, 274 F.2d 669 (CCPA 1960)).
Regarding claim 6, Chen ‘482 teaches wherein the system synchronization unit comprises: a synchronized light detection unit (Chen ‘482 at least suggests figs. 7, 9 including software), configured to convert received synchronized light of the quantum communication system into a synchronized signal, so as to acquire the clock of the quantum communication system (“a synchronous light detection unit configured to receive the synchronous light to form a synchronous electric signal; a phase-locked loop, which is configured to receive the synchronous electrical signal, forming a system recovery clock signal with a period of T” at p. 3).
Regarding claim 11, while Chen ‘482 teaches wherein the clock of the quantum communication system comprises a clock of a signal (fig. 8, item 401; fig. 10, item 403) of the quantum communication system,
Chen ‘482 does not teach the signal being an encoded signal.
Chen ‘482 teaches an encoded signal (“encoded synchronous signal;” at p. 6).
It would have been obvious to one of ordinary skill in the art before the filing date of the invention for Chen ‘482’s signal to be an encoded signal as taught by Chen ‘482 to “improve[[s]] the detection efficiency of the single photon detector.” Chen ‘482 p. 3.
Allowable Subject Matter
Claims 5 and 7–9 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.
Conclusion
THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicants are reminded of the extension of time policy as set forth in 37 C.F.R. § 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 § 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 DAVID P. ZARKA whose telephone number is (703) 756-5746. The Examiner can normally be reached Monday–Friday from 9:30AM–6PM ET.
If attempts to reach the Examiner by telephone are unsuccessful, the Examiner’s supervisor, Vivek Srivastava, can be reached at (571) 272-7304. The fax phone number for the organization where this application or proceeding is assigned is (571) 273-8300.
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/DAVID P ZARKA/PATENT EXAMINER, Art Unit 2449
1 The Examiner relies on an English translation provided by CLARIVATE ANALYTICS.
2 The Examiner relies on an English translation provided by CLARIVATE ANALYTICS.