DETAILED ACTION
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 § 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.
Claims 8-10, 12 and 13 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Yang et al. (“Yang”) (Yang, Chunyong & Xu, Chuang & Ni, Wenjun & Gan, Yu & Hou, Jin & Chen, Shaoping. (2017). Turbulence heterodyne coherent mitigation of orbital angular momentum multiplexing in a free space optical link by auxiliary light. Optics Express. 25. 25612-25624).
Regarding claim 8, Yang discloses a system for free space optical (FSO) communications, the system comprising: a transmitter configured to transmit an optical data beam containing data and a frequency offset optical pilot beam, the optical data beam and the frequency offset optical pilot beam being transmitted over free space (fig. 1 and section 2, 1st and last paragraphs, OAM beam is the optical data beam and Gaussian beam is the pilot beam, and ∆ω is the frequency offset between the OAM beam and the pilot/LO beam); at least one photodetector configured to receive the optical data beam and the frequency offset optical pilot beam (fig. 1 PDs); and a processor connected to the at least one photodetector and configured to compensate for optical distortions between the transmitter and the at least one photodetector by using a conjugate of the received frequency offset optical pilot beam to cancel distortions in the received optical data beam (fig. 1 in light of section 1, last paragraph and fig. 2 and section 3, first two paragraphs, the distorted phase counteracted, where UG* is the pilot beam conjugate).
Regarding claim 9, Yang discloses the system of claim 8, wherein the frequency offset optical pilot beam is transmitted coaxially with the optical data beam (fig. 1, PBS1 output beam).
Regarding claim 10, Yang discloses the system of claim 8, wherein the frequency offset optical pilot beam is used as an oscillator for coherent detection at a receiver that includes the at least one photodetector (fig. 1 and section 2, 1st paragraph, pilot beam split by PBS2 used as local oscillator at each BSn).
Regarding claim 12, Yang discloses the system of claim 8, wherein the frequency offset optical pilot beam is a continuous wave signal (fig. 1 and section 2, 1st paragraph, the pilot beam disclosed without modulation and used as a local oscillation relative to the QPSK data transmission means it is necessarily a continuous wave signal).
Regarding claim 13, Yang discloses the system of claim 8, wherein compensating for the optical distortions includes mixing each Laguerre-Gaussian component of the optical data beam with a corresponding conjugate Laguerre-Gaussian component of the frequency offset optical pilot beam (fig. 1 and section 2, 1st paragraph and fig. 2 and section 3, 2nd paragraph, where LG02 is the data beam component, and the pilot beam SLM(s) for the “special phase pattern”, for the interference as UG*, reads on pilot beam as corresponding conjugate LG component).
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.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Yang (Yang, Chunyong & Xu, Chuang & Ni, Wenjun & Gan, Yu & Hou, Jin & Chen, Shaoping. (2017). Turbulence heterodyne coherent mitigation of orbital angular momentum multiplexing in a free space optical link by auxiliary light. Optics Express. 25. 25612-25624).
Regarding claim 11, Yang discloses the system of claim 8, and discloses a wavelength spec of 1550 nm (section 3, 2nd paragraph, i.e. a 193 THz signal), but does not explain that a frequency difference between the optical data beam and the frequency offset optical pilot beam is orders of magnitude smaller than carrier frequencies of the optical data beam and the optical pilot beam. However, Yang discloses ∆ω for the frequency offset (section 2 last paragraph), and ∆ω being orders of magnitude smaller than 193 THz is desirable for coherent detection. 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 small ∆ω between the main and pilot signal, an orders of magnitude smaller frequence difference value than the 193 THz value, so the heterodyne coherent detection of Yang, using the signal and pilot/LO beams, is effective yet avoiding the precision needed to maintain exact equality of the signal and pilot/LO beams as would be the case for legacy homodyne coherent detection.
Allowable Subject Matter
Claims 1-7 and 14-20 are allowed.
Response to Arguments
Applicant's arguments filed 20 February 2026 have been fully considered but they are not persuasive with respect to the claim 8 claim set. Applicant argues that “the term ‘frequency offset’ appears nowhere in Yang…”; however, ∆ω in Yang is a frequency offset.
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 NATHAN M CORS whose telephone number is (571)272-3028. The examiner can normally be reached Monday-Friday.
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/NATHAN M CORS/Primary Examiner, Art Unit 2634
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