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 .
Drawings
The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the “swept frequency synthesizer” (claim 8) must be shown or the feature(s) canceled from the claim(s). No new matter should be entered.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Claim Rejections - 35 USC § 102
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 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.
Claim(s) 1-3, 6, 7, 9, 11-13, 16, and 18 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Huang et al. (US 2019/0238178 A1).
Regarding claim 1, Huang et al. discloses a distributed acoustic sensing (DAS) system (fig. 1), comprising: a distributed acoustic sensing (DAS) station, comprising: a DAS transmitter (optical pulse source and acoustic source), arranged to launch an outbound DAS signal through an optical fiber (¶ [0037]), over at least one span (the DAS signal is sent over a span); a DAS receiver, arranged to receive a backscatter Rayleigh signal, based upon the DAS signal (a receiver is arranged to receive a backscatter Rayleigh signal; fig. 5 and ¶ [0037]); and at least one component (pulse generating circuit; fig. 3), coupled to the DAS transmitter, the DAS receiver, or both, and arranged to increase a sensitivity for sensing of the DAS system (the frequency-hopping pulse generation circuit is coupled to the DAS transmitter and receiver and arranged to increase sensing sensitivity; ¶¶ [0003-0004, 0042]).
Regarding claims 2, Huang et al. discloses wherein the at least one component (pulse generating circuit; fig. 3) comprises: a first acousto-optic modulator (AOM-1), arranged to receive the outbound DAS signal (AOM-1 receives an outbound DAS signal; ¶ [0043]); a first amplifier (optical amplifier in recirculating loop; fig. 3 and ¶ [0042]), to receive a first output signal of the first AOM (AOM-1) and to increase an intensity of the outbound DAS signal (the recirculation loop reduces the influence of noise which increases an intensity of the DAS signal; ¶ [0044]); and a second AOM (AOM-2), arranged to receive an output of the first amplifier (AOM-2 receives an output of the optical amplifier; fig. 3); receiving the outbound DAS signal at a first acousto-optic modulator (AOM); receiving and an increasing an intensity of a first output signal of the first AOM at a first amplifier; and receiving an output of the first amplifier at a second AOM.
Regarding claim 3, Huang et al. discloses wherein a first width of the output signal of the first AOM (AOM-1) is greater than a second width of a second output signal of the second AOM (AOM-2), and wherein the second output signal is centered in time on the first output signal (a width between pulses, or period, of the DAS signal from AOM-2 can be tuned to be less than a period of AOM-1; fig. 3 and ¶ [0044]).
Regarding claims 6 and 7, Huang et al. discloses wherein the at least one component (pulse generating circuit; fig. 3) comprises: a narrow bandwidth optical filter (optical bandpass filter; ¶ [0044]), located in the DAS receiver and arranged to receive the backscatter Rayleigh signal, wherein the narrow bandwidth optical filter (BPF) has a bandwidth, the bandwidth being less than 10 GHz (bandwidth of filtered backscatter Rayleigh signal is less than 10 GHz; fig. 5); wherein the bandwidth is less than 1 GHz (bandwidth of filtered backscatter Rayleigh signal is less than 1 GHz; fig. 5).
Regarding claim 9, Huang et al. discloses a receiver power tracker (erbium-doped fiber amplifier EDFA; ¶ [0042]), arranged to attenuate or reduce an amplification of the backscatter Rayleigh signal, from a beginning of the at least one span (EDFA gain inside the recirculation loop equalizes power levels; ¶ [0044]).
Regarding method claims 11-13, 16, and 18 are the method steps thereof are met by the operation of the apparatus of Huang et al. as set forth above.
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(s) 4 and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Huang et al. (US 2019/0238178 A1) in view of Alfataierge (US 2023/0184622 A1).
Regarding claims 4 and 14, Huang et al. discloses the invention as set forth above with regard to claims 1 and 11, respectively.
Although Huang et al. is silent on the particular pulse width formula, the relationship between refractive index, gauge length, and pulse width is known in the art of DAS optical fiber sensing.
Alfataierge teaches that a pulse width is equal to n*GL/c, where n is a refractive index of the optical fiber, GL is a gauge length of the optical fiber in meters, and c is speed of light (GL
=
C
(
P
w
+
P
s
)
/
n
,where Pw is a pulse width, n is a refractive index of the optical fiber, and c is the speed of light in a vacuum and with algebraic manipulation arrives at the claimed relationship; ¶ [0021]).
It would have been obvious to one of ordinary skill in the art at the time of filing to modify the apparatus of Huang et al. with the pulse width relationship as taught in Alfataierge as this would apply a known technique to a known device to yield predictable results.
Claim(s) 5, 15, and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Huang et al. (US 2019/0238178 A1) in view of Bhatta et al. (Dynamic Measurements of 1000 Microstrains Using Chirped-Pulse Phase-Sensitive Optical Time-Domain Reflectometery).
Regarding claims 5 and 15, Huang et al. discloses the invention as set forth above with regard to claims 1 and 11, respectively, and further discloses, receiving the outbound DAS signal at a first amplifier (optical amplifier in recirculating loop; fig. 3 and ¶ [0042]); and receiving an output of the first amplifier at a narrow bandwidth optical filter (optical bandpass filter; ¶ [0044]).
Regarding claim 20, Huang et al. discloses a distributed acoustic sensing (DAS) system (fig. 1), comprising: a distributed acoustic sensing (DAS) station, comprising: a DAS transmitter (optical pulse source and acoustic source), arranged to launch an outbound DAS signal through an optical fiber (¶ [0037]), over at least one span (the DAS signal is sent over a span); a DAS receiver, arranged to receive a backscatter Rayleigh signal, based upon the DAS signal (a receiver is arranged to receive a backscatter Rayleigh signal; fig. 5 and ¶ [0037]); a first acousto-optic modulator (AOM-1), arranged to receive the outbound DAS signal (AOM-1 receives an outbound DAS signal; ¶ [0043]); a first amplifier (optical amplifier in recirculating loop; fig. 3 and ¶ [0042]), to receive a first output signal of the first AOM (AOM-1) and to increase an intensity of the outbound DAS signal (the recirculation loop reduces the influence of noise which increases an intensity of the DAS signal; ¶ [0044]); and a second AOM (AOM-2), arranged to receive an output of the first amplifier (AOM-2 receives an output of the optical amplifier; fig. 3); and a narrow bandwidth optical filter (optical bandpass filter), arranged to receive an output of the first amplifier at a narrow bandwidth optical filter (¶ [0044]).
Huang et al. is silent on the optical filter bandwidth is between 1 and 10 GHz.
Bhatta et al. teaches a DAS fiber optic sensing system (fig. 1) wherein a narrow bandwidth optical filter (second narrowband filter) has a bandwidth, the bandwidth being between 1 GHz and 10 GHz (after additional amplification, spectral cleaning by the second narrowband filter, and power adjustment, the Rayleigh back-scattered signal enters the photodetector of 9.5 GHz bandwidth; page 4891, col. 1, last paragraph).
It would have been obvious to one of ordinary skill in the art at the time of filing to modify the apparatus of Huang et al. with the filter bandwidth as taught in Bhatta et al. to provide a DAS system that more accurately measures large strains over a span (page 4893, Conclusions, first paragraph).
Claim(s) 8 and 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Huang et al. (US 2019/0238178 A1) in view of Hartog et al. (US 2013/00113629 A1).
Regarding claims 8 and 17, Huang et al. discloses the invention as set forth above with regard to claims 1 and 11, respectively.
Huang et al. is silent on a frequency shifter.
Hartog et al. teaches a fiber optic sensing system (fig. 23) including an optical frequency shifter (¶ [0128]), coupled between a transmitter (102) and receiver (522); and a swept frequency synthesizer (510), coupled to the optical frequency shifter (¶ [0130]).
It would have been obvious to one of ordinary skill in the art at the time of filing to modify the apparatus of Huang et al. with the frequency shifting of Hartog et al. to improve detection of backscatter signals in an optical fiber by frequency shifting the pulse signal (Hartog et al., ¶¶ [0043-0044]).
Allowable Subject Matter
Claims 10 and 19 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.
The prior art does not disclose or suggest “wherein the receiver power tracker comprises: an optical programable attenuator having an attenuation that is relatively larger at the beginning of the at least one span, wherein the attenuation gradually decreases to zero at an end of the at least one span; or an optical pre-amplifier having a relatively smaller current or relatively smaller gain for the outbound DAS signal from the beginning of the at least one span, and a relatively larger current or a relatively larger gain for the outbound DAS signal, when coming from an end of the at least one span” in combination with the remaining claim elements as recited in claims 10 and 19.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Erika J. Villaluna whose telephone number is (571)272-8348. The examiner can normally be reached Mon-Fri 9:00 am - 5:30 pm.
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, Stephanie Bloss can be reached at (571) 272-3555. 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.
/ERIKA J. VILLALUNA/Primary Examiner, Art Unit 2852