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 November 19, 2025 has been fully considered and entered.
Claim Objections
Regarding claims 1 and 11, the limitation “a light source remote from the first communication device and the second communication device” is objected to because the light source appears to be disposed in the second communication device and thus cannot be remote from the second communication device. Both claims previously recite “a waveguide configured to receive photons from an optical fiber coupled to the first communication device and the second communication device.” Since the first communication device corresponds to “Alice” in Fig. 2, the second device must be “Charlie”, since they are coupled together by fiber 308. This is also supported by the disclosure, such as paragraph 0040 stating “Alice and Bob may each be separately communicatively coupled with Charlie via optical fibers” and paragraph 0058 describing “the optical fiber length from Charlie to Alice is ten km longer than the length of the optical fiber from Charlie to Bob.” Since Charlie (306 in Fig. 2) corresponds to the second communication device and contains the laser (312), the laser cannot be remote from the second communication device. For the purposes of examination, the limitation will be changed to “a light source remote from the first communication device”.
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 1-4, 9-14, 19 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Fish et al. (US 9,647,426 B1) in view of Hu et al. (CN 209517161 U).
Regarding claims 1 and 11, Fish discloses a method of assembling and a photonic integrated circuit comprising: a waveguide (550 in Fig. 5A is an optical path, which inherently must include some element to guide an optical wave) configured to receive photons (the optical path receives light, which comprises photons) from an optical fiber (column 5, lines 40-42) and direct the photons in a loop formed by the waveguide; an intensity modulator (510; column 4, lines 45-50 describes how the optical amplifiers adjust the intensity of the light) coupled with the waveguide within the loop formed by the waveguide and configured to adjust a number of the photons between a key level and a decoy level (adjusting the intensity of the light corresponds to the claimed adjusting a number of the photons between a key level and a decoy level, since adjusting the intensity inherently changes the number of photons and the key level and the decoy level have not been further defined in the claims); and a phase shifter (508; column 4, lines 45-50 describes how the modulators adjust the phase of the light) coupled with the waveguide within the loop formed by the waveguide and configured to change a phase of the photons, wherein the waveguide is configured to direct one or more of the photons back out of the optical fiber after the one or more of the photons has passed through the loop formed by the waveguide with a polarization state of the one or more of the photons rotated by 90 degrees (see column 5, lines 34 to column 6, line 22; specifically Fig. 5A shows TE + TM light entering the photonic integrated circuit and TM + TE light exiting; Fig. 5B shows the path of TE-mode light traversing the optical path and exiting as TM-mode light).
Still regarding claims 1 and 11, Fish teaches the claimed invention except for a variable optical attenuator. Hu discloses a quantum key distribution system (Fig. 6) using a photonic integrated circuit for a first communication device (“Alice” contains quantum terminal unit 1 comprising a photonic integrated circuit) configured to communicate with a second communication device (401), the photonic integrated circuit comprising a waveguide configured to receive photons and coupled to the first communication device and the second communication device and a waveguide loop (phase modulator 107, polarization modulator 108, intensity modulator 109 and adjustable attenuator 110 form a loop, which must include a waveguide to direct the photons within the loop), the photons generated at a full light level by a light source (401) remote from the first communication device (401 is remote from waveguide loop in quantum terminal unit 1 of Alice) and comprising an intensity modulator (109) adjacent to a variable optical attenuator (110) which is configured to reduce the signal intensity from the full light level to a reduced light level (Hu specifically states “adjusting the variable optical attenuator so as to ensure the average photon number is [at an] appointed value”) and a phase shifter (107) configured to randomly modulate a phase of the photons in a light pulse (claim 7). Hu further discloses quantum keys used to send information carried by single photons and an attenuated laser pulse with an average number of photons per pulse being below 1 (Hu states “the average photon number of variable optical attenuator to ensure reflection to a quantum channel is less than 1”). Since both inventions relate to optical devices, one of ordinary skill in the art at the time of the invention would have found it obvious to use a variable optical attenuator to reduce a light level such that there is no more than one photon during key generation as disclosed by Hu in the photonic integrated circuit of Fish for the purpose of encoding and transmitting information with enhanced security. Since Hu discloses the variable optical attenuator directly adjacent to the intensity modulator (see Fig. 6), in the proposed combination it would be obvious to dispose the variable optical attenuator next to the intensity modulator in the photonic integrated circuit taught by Fish, which would be within the loop formed by the waveguide. Further, Fish discloses directing light to the photonic integrated circuit from an optical fiber (see column 5, lines 40-42).
Regarding claims 2 and 12, Fish discloses a polarizing beamsplitter and polarization rotator (504) configured to be coupled with an optical fiber and to receive photons from the optical fiber, the polarizing beamsplitter and polarization rotator configured to direct incident horizontally polarized photons in one direction in the waveguide and to direct incident vertically polarized photons in an opposite direction in the waveguide (see column 5, lines 40-55; the TE and TM polarization states are also known as the horizontal and vertical polarizations respectively).
Regarding claims 3, 4, 13 and 14, Fish further discloses optical taps (520, 525) coupled with the waveguide and configured to direct a portion of the photons to photodetectors (514), wherein the one or more of the intensity modulator or the phase shifter is or are disposed along the waveguide between the optical taps in Figs. 5A. The proposed combination of Fish and Hu teaches the claimed invention except for specifically stating the photodetectors used for detection of bright light attacks. However, one of ordinary skill in the art at the time of the invention would have found it obvious to use the photodetectors to detect any abnormal state of the light, including bright light attacks for the purpose of ensuring the photonic integrated circuit is functioning optimally.
Regarding claims 9 and 19, Fish discloses the photonic integrated circuit does not include a Faraday mirror since the drawings and specification do not refer to any Faraday mirror.
Regarding claims 10 and 20, Fish further discloses filters to select different wavelength bands in column 2, lines 23-26. The proposed combination of Fish and Hu teaches the claimed invention except for specifically stating a narrow band optical filter at an entrance of the waveguide. However, one of ordinary skill in the art at the time of the invention would have found it obvious to use any type of optical filter, including narrow band optical filters which are well-known and commonly used in the art, for the purpose of selecting a desired wavelength range for operation of the photonic integrated circuit.
Response to Arguments
Applicant's arguments, filed November 19, 2025, with respect to claims have been considered but are moot in view of the new grounds of rejection.
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 11, 2026