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 OFFICE ACTION
Information Disclosure Statement
The information disclosure statement (IDS) submitted on December 19, 2024, and December 11, 2025 in compliance with the provisions of 37 CFR 1.97 has been considered by the examiner and made of record in the application file.
Claim Status
Claims 1-20 are pending in this application and are under examination in this Office Action. No claims have been allowed.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
Claims 4 and 15 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Regarding claim 4,
Claim 4 depends from claim 2 and recites that “updating the SRS transfer coefficient comprises” acquiring a third OTDR trace and “determining an SRS transfer correction coefficient according to the first OTDR trace and the third OTDR trace.” Claim 4 then recites “updating the SRS transition coefficient according to the SRS transition correction coefficient.”
There is a lack of antecedent basis for “the SRS transition coefficient” and “the SRS transition correction coefficient” because claim 4 previously introduced an “SRS transfer coefficient” and an “SRS transfer correction coefficient,” not an SRS transition coefficient or an SRS transition correction coefficient. The change from “transfer” to “transition” introduces different terminology for the same claimed updating operation without identifying whether the newly recited “transition” coefficients are intended to be the previously recited “transfer” coefficients or separate and distinct coefficients.
Moreover, the ambiguity is not cured by the specification. Paragraph [0056] likewise first describes “updating the SRS transfer coefficient” and determining an “SRS transfer correction coefficient,” but then states that the “SRS transition coefficient” is updated according to the “SRS transition correction coefficient.” Thus, the intrinsic disclosure
repeats the same inconsistent terminology rather than defining a distinction between an SRS transfer coefficient and an SRS transition coefficient. As written, it is unclear whether claim 4 intends one pair of coefficients or two different pairs of coefficients. Accordingly, the metes and bounds of claim 4 are not reasonably certain, and claim 4 is indefinite.
Regarding claim 15,
Claim 15 depends from claim 13 and recites that “updating the SRS transfer coefficient comprises” acquiring a third OTDR trace and “determining an SRS transfer correction coefficient according to the first OTDR trace and the third OTDR trace.” Claim 15 then recites “updating the SRS transition coefficient according to the SRS transition correction coefficient.”
There is a lack of antecedent basis for “the SRS transition coefficient” and “the SRS transition correction coefficient” because claim 15 previously introduced an “SRS transfer coefficient” and an “SRS transfer correction coefficient,” not an SRS transition coefficient or an SRS transition correction coefficient. The terminology is material because claim 15 expressly states that the step is directed to updating the SRS transfer coefficient, yet the final limitation requires updating an SRS transition coefficient using an SRS transition correction coefficient.
The specification does not provide an objective basis for treating the recited “transition” coefficients as distinct from, or necessarily identical to, the recited “transfer”
coefficients. Instead, paragraph [0056] repeats the same inconsistent terminology. As written, it is unclear whether the final updating step of claim 15 operates on the previously recited SRS transfer coefficient using the previously recited SRS transfer correction coefficient, or instead requires different transition coefficients that are otherwise undefined. Accordingly, the metes and bounds of claim 15 are not reasonably certain, and claim 15 is indefinite.
Accordingly, claims 4 and 15 are indefinite under 35 U.S.C. § 112(b).
Claim Rejections – 35 U.S.C. § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for the 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.
As reiterated by the Supreme Court in KSR, and as set forth in MPEP 2141 (R-01.2024), II, the factual inquiries of Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), applied for establishing a background for determining obviousness under 35 U.S.C. § 103, are summarized as follows:
Determining the scope and content of the prior art;
Ascertaining the differences between the prior art and the claims at issue;
Resolving the level of ordinary skill in the pertinent art; and
Considering objective evidence indicative of obviousness or non-obviousness, if present.
This application currently names joint inventors. In considering patentability of the claims, the examiner presumes that the subject matter disclosed in the prior art was created by another (i.e., not by the inventive entity) unless proven otherwise. Applicant is advised of the obligation under 37 C.F.R. § 1.56 to point out the inventor and effective filing dates of each claim, and any evidence of common ownership/assignment as of the effective filing date, so that the examiner may properly consider the applicability of 35 U.S.C. § 102(b)(2)(C) for any potential 35 U.S.C. § 102(a)(2) prior art against the claimed invention(s).
For purposes of the rejection below, Li et al. (WO2023284444A1, PCT/CN2022/097350) is relied upon as AIA 35 U.S.C. § 102(a)(2) prior art. Li's PCT international filing date is June 7, 2022, which precedes the June 30, 2022 priority date identified for the present application. Under MPEP §§ 2154.01(a)-(b), a WIPO-published PCT application designating the United States is deemed published under 35 U.S.C. § 122(b) for AIA § 102(a)(2) purposes, and its prior-art effect is determined under AIA § 102(d) with respect to the subject matter relied upon. The WIPO publication names a different inventive entity. This reliance remains subject to any evidence establishing an applicable § 102(b)(2) exception.
Claims 1, 11, and 12 are rejected under 35 U.S.C. § 103 as being unpatentable over Li et al. (WO2023284444A1) in view of Holland (US6519026B1) and Rad et al. (US20160072576A1).
Claim 1
Li expressly teaches the same overall problem addressed by claim 1: correcting an OTDR trace whose apparent fiber attenuation is distorted by stimulated Raman scattering produced by simultaneously transmitted service light.
Li explains that an OTDR trace is measured under different service-light conditions, the SRS transfer amount is calculated from those measurements, and an OTDR curve not affected by SRS is recovered.
More particularly, Li states: “the fiber loss coefficient measured when there is no service light is about 0.19dB/km, and after injecting C band service light and C band+L band service light respectively, the measured fiber loss coefficient is about 0.25dB/km and 0.35dB respectively /km. ... In view of this, the technical solution of the present application proposes an optical time domain reflectometer signal detection method, respectively measuring OTDR test curves under two different service light conditions. Through these two curves, and the energy relationship injected by the service light during the two measurements, the magnitude of the SRS transfer energy of the OTDR signal light is calculated, and then the OTDR signal curve that is not affected by the SRS is recovered, and the correct measurement result is obtained.” [Li, translated p. 10; FIG. 5].
Thus, Li expressly provides the claimed use of a first condition in which service light is absent, determination of the fiber-loss behavior from that condition, a second condition in which service light is present, determination of an SRS contribution from the changed condition, and correction of the OTDR measurement by removal of the SRS contribution.
With respect to the expressly recited disabled/enabled service-wavelength states, Li further teaches: “The dotted line shown in Figure 7 represents the OTDR curve not affected by SRS measured after turning off all service lights in the offline scenario, that is, the OTDR curve without SRS effect.... The solid line represents the OTDR test curve measured after all the service lights (that is, including 120 service lights according to the interval of 50 GHz), that is, trace1, and the included SRS transfer energy is ΔPSRS1.... The dotted line represents the OTDR test curve measured after closing half of the service optical channels at equal intervals ... which is trace2, and the SRS transfer energy contained is ΔPSRS2.... ΔPSRS1 and ΔPSRS2 can be calculated ... and finally the restored OTDR curve can be obtained according to formulas (11) and (12).” [Li, translated p. 15; FIG. 7].
Accordingly, Li expressly teaches taking an OTDR trace when service wavelengths are disabled and taking one or more OTDR traces when service wavelengths are enabled.
The fact that Li also describes a partially loaded state does not detract from the express teaching of the all-service-off state and the all-service-on state.
For the claimed first and second OTDR traces and calculation of the SRS transfer from the traces, Li teaches: “before calculating the magnitude of the first SRS energy transfer, the first OTDR test curve corresponding to the first service light and the second OTDR test curve
corresponding to the second service light need to be measured respectively.... Then, the difference in energy transfer size between the above two OTDR measurement results satisfies: Δtrace=trace1-trace2.... Δtrace = trace1 - trace2 = ΔPSRS1 - ΔPSRS2.” [Li, translated pp. 13-14; formulas (4)-(5)].
Li then expressly corrects the measured trace by removing the calculated SRS transfer: “according to the first OTDR test curve trace1 ... the OTDR signal curve trace0 not affected by SRS can be recovered as: trace0 = trace1 - ΔPSRS1.... Similarly, according to the second OTDR test curve trace2 and the second SRS energy transfer size ... the target OTDR test curve trace0 can also be generated.... It should be noted that the recovered OTDR signal curves ... are exactly the same.” [Li, translated p. 14; formulas (11)-(12)].
Li therefore supplies the service-wavelength OFF/ON measurement architecture and the subtraction of the SRS transfer amount.
However, claim 1 labels the separated parameters as a “fiber loss coefficient” and an “SRS transfer coefficient,” and recites establishing a parameter-decoupling equation according to those coefficients. Holland expressly supplies that coefficient-based mathematical treatment of the same OTDR/SRS problem.
Holland explains: “where α is the attenuation coefficient (1/km) of the fiber, γ' is the effective Raman gain coefficient (1/km), g is the Raman gain factor, P is the average traffic signal power (W), A is the effective core area of the fiber (m²), and Leff is the effective length of the fiber (km).” [Holland, col. 4; equations (1)-(3); FIG. 3].
Holland further teaches determining the SRS/Raman coefficient and then correcting the OTDR trace: “using Eq. (6), the effective Raman gain coefficient γ' can be determined from the
measured “out-of-band” back-scattering.... Once the Raman gain coefficient γ' has been determined, it can then be inserted into Eq. (1) to yield the Raman gain G, which in turn is used as the basis to offset the test signal back-scattering, thereby canceling the effects of the Raman non-linearities.” [Holland, cols. 5-6].
Holland additionally makes the point-by-point trace correction explicit: “adjusting or depressing each data point along OTDR trace 155 by the Raman gain G (dB) divided by the corresponding distance Z along the fiber 105 yields OTDR trace 160.... Hence, this “out-of-band” offsetting cancels the effects of the Raman non-linearities, greatly improving the accuracy of the OTDR by restoring the back-scattered signal back to its true reading.” [Holland, col. 7; FIG. 4].
The claimed “parameter decoupling equation” is therefore taught by the combined references even though the references do not use applicant’s chosen label.
Li mathematically separates the SRS transfer term from the OTDR trace and subtracts it to recover an SRS-free trace.
Holland expressly identifies the independent fiber attenuation coefficient α and effective Raman gain coefficient γ', calculates Raman gain from those parameters, and uses the gain to correct the trace. The claimed decoupling is the same mathematical separation of ordinary fiber attenuation from SRS-induced distortion.
Rad independently reinforces the same two-condition coefficient separation and eliminates any question as to using a reference condition and an enabled Raman/SRS condition at the same OTDR wavelength.
Rad states: “the main difference between conventional OTDR trace information and OTDR trace information with Raman amplification ON is due to the contribution of the nonlinear Raman scattering.... Accordingly, it is possible to estimate the Raman gain profile G(Z), by subtracting the OTDR trace with Raman amplification OFF from the OTDR trace with Raman amplification ON.” [Rad, ¶¶ [0033]-[0034]].
Rad also teaches: “a reference trace is derived, which is indicative of a distributed optical performance of the optical fiber link with no Raman amplification.... [A] reference OTDR trace measurement with Raman Amplification OFF [is performed].... Subsequently, an in-service OTDR trace measurement is performed, using the same OTDR pulse wavelength(s) with Raman Amplification ON.... Using the reference and in-service OTDR traces ... the cumulative Raman gain profile ... can be calculated.” [Rad, ¶ [0042]; FIGS. 2-3D].
Accordingly, the combined references teach every limitation of claim 1: (i) an OTDR trace-correction method; (ii) a mathematical separation/decoupling of fiber attenuation and SRS/Raman transfer; (iii) an OTDR trace with service light disabled; (iv) determination of fiber loss from the no-service/no-Raman condition; (v) an OTDR trace with service light enabled; (vi) determination of the SRS transfer from the two conditions; and (vii) correction of a test trace using the separately determined fiber-loss and SRS/Raman parameters.
One of ordinary skill in the art would have been motivated to combine Li, Holland, and Rad because all three references address the identical measurement error: an OTDR trace is distorted when Raman/SRS energy transfer is present in a wavelength-multiplexed optical fiber.
Li provides the closest service-channel OFF/ON implementation and expressly restores an SRS-free curve from traces measured under different service-light conditions.
Holland provides the explicit attenuation coefficient and Raman gain coefficient equations, including numerical calculation of the Raman coefficient and point-by-point correction of the trace.
Rad provides the same-wavelength reference/in-service OTDR architecture and expressly derives a Raman-gain profile and attenuation/loss profile from the reference and active traces. A skilled artisan seeking to implement Li with physically meaningful, reusable correction parameters would have had a direct reason to employ the coefficient formulation of Holland and the reference/in-service profile calculation of Rad.
The combination would merely apply known coefficient-based Raman correction mathematics to the very service-light SRS correction problem identified by Li, with the predictable result of separating ordinary fiber loss from SRS-induced trace distortion and improving OTDR accuracy. No change in the principle of operation of any reference would be required.
Therefore, claim 1 would have been obvious.
Claim 11
Claim 11 is an independent electronic-device claim. It requires a memory storing a computer program and a processor that executes the program to perform the same OTDR trace-correction operations recited in claim 1: establishing a parameter-decoupling equation using a fiber-loss coefficient and an SRS transfer coefficient; acquiring a first OTDR trace with the OTN
service wavelength disabled; determining the fiber-loss coefficient; acquiring a second OTDR trace with the service wavelength enabled; determining the SRS transfer coefficient from the first and second traces; and correcting an OTDR test trace according to the two separated coefficients.
Li expressly teaches the processor-and-memory structure. Li states: “the communication device 2000 includes a processor 2010, a transceiver 2020 and a memory 2030. Wherein, the processor 2010, the transceiver 2020 and the memory 2030 communicate with each other through an internal connection path, the memory 2030 is used to store instructions, and the processor 2010 is used to execute the instructions stored in the memory 2030.... The memory 2030 may include read-only memory and random-access memory, and provide instructions and data to the processor.... The processor 2010 may be used to execute the instructions stored in the memory 2030, and when the processor 2010 executes the instructions stored in the memory, the processor 2010 is used to execute the steps and/or process.” [Li, translated p. 17; FIG. 10].
Li also teaches the substantive service-wavelength OFF/ON trace-acquisition and SRS-removal operations performed by that processor.
Li explains: “the technical solution of the present application proposes an optical time domain reflectometer signal detection method, respectively measuring OTDR test curves under two different service light conditions. Through these two curves, and the energy relationship injected by the service light during the two measurements, the magnitude of the SRS transfer energy of the OTDR signal light is calculated, and then the OTDR signal curve that is not
affected by the SRS is recovered, and the correct measurement result is obtained.” [Li, translated p. 10; FIG. 5].
Li further expressly identifies the disabled and enabled conditions: “The dotted line shown in Figure 7 represents the OTDR curve not affected by SRS measured after turning off all service lights in the offline scenario.... The solid line represents the OTDR test curve measured after all the service lights ... [are present], that is, trace1, and the included SRS transfer energy is ΔPSRS1....” [Li, translated p. 15; FIG. 7]. Li then states that the SRS-free trace is recovered by “trace0 = trace1 - ΔPSRS1” and likewise from the second measured trace. [Li, translated p. 14; formulas (11)-(12)].
Holland supplies the expressly coefficient-based mathematical decoupling required by claim 11. Holland teaches: “where α is the attenuation coefficient (1/km) of the fiber, γ' is the effective Raman gain coefficient (1/km), g is the Raman gain factor, P is the average traffic signal power (W), A is the effective core area of the fiber (m²), and Leff is the effective length of the fiber (km).” [Holland, col. 4; equations (1)-(3); FIG. 3]. Holland further teaches: “using Eq. (6), the effective Raman gain coefficient γ' can be determined from the measured ‘out-of-band’ back-scattering.... Once the Raman gain coefficient γ' has been determined, it can then be
inserted into Eq. (1) to yield the Raman gain G, which in turn is used as the basis to offset the test signal back-scattering, thereby canceling the effects of the Raman non-linearities.” [Holland, cols. 5-6].
Rad independently teaches the same reference/in-service architecture at the same OTDR wavelength and the separation of the Raman contribution from ordinary link loss: “a reference
OTDR trace measurement with Raman Amplification OFF [is performed].... Subsequently, an in-service OTDR trace measurement is performed, using the same OTDR pulse wavelength(s) with Raman Amplification ON.... Using the reference and in-service OTDR traces ... the cumulative Raman gain profile ... can be calculated.” [Rad, ¶ [0042]; FIGS. 2-3D]. Rad additionally teaches that the attenuation/loss profile can be derived after the Raman contribution is separated. [Rad, ¶ [0051]; FIG. 5].
Accordingly, Li provides the claimed memory, processor, service-wavelength OFF/ON measurements, SRS-energy determination, and corrected OTDR trace; Holland provides the fiber attenuation coefficient, Raman/SRS coefficient equations, and point-by-point correction mathematics; and Rad provides the same-wavelength reference/in-service profile calculation. Every substantive method limitation recited in claim 11 is therefore present in the combined teachings, and Li expressly implements those operations using stored instructions executed by a processor.
One of ordinary skill in the art would have been motivated to implement the Li/Holland/Rad correction technique in Li's disclosed processor-and-memory device because the method inherently requires storing at least the first and second OTDR traces, storing the loss and
SRS/Raman parameters, executing numerical coefficient calculations, and applying the resulting correction to measured trace data. Using Li's processor 2010 and memory 2030 for those calculations is the expressly disclosed and predictable implementation, not a change in the references' principle of operation. Therefore, claim 11 would have been obvious.
Claim 12
Claim 12 is an independent non-transitory computer-readable-storage-medium claim. It requires a stored program which, when executed by a processor, causes the processor to perform the same substantive OTDR trace-correction operations recited in claim 1.
Li expressly teaches the claimed computer-readable storage-medium implementation: “the present application provides a computer-readable storage medium, where computer instructions are stored in the computer-readable storage medium, and when the computer instructions are run on a computer, [the disclosed optical-fiber measurement method] is executed.” [Li, translated p. 5].
The method stored on that medium is the same service-light-dependent OTDR correction method relied upon for claim 1.
Li teaches measuring OTDR curves under different service-light conditions, determining the SRS transfer from those measurements, and recovering an OTDR curve not affected by SRS. Li states: “the magnitude of the SRS transfer energy of the OTDR signal light is calculated, and then the OTDR signal curve that is not affected by the SRS is recovered, and the correct measurement result is obtained.” [Li, translated p. 10; FIG. 5]. Li further teaches an all-
service-off reference condition and an all-service-on condition, followed by restoration of trace0 according to formulas (11) and (12). [Li, translated pp. 14-15; FIG. 7].
Holland supplies the coefficient form required by the stored program. Holland identifies “α” as the fiber attenuation coefficient and “γ'” as the effective Raman gain coefficient and explains that the Raman gain coefficient is determined from measured back-scattering and inserted into the Raman-gain equation to offset the measured test-signal back-scattering. [Holland, cols. 4-6; equations (1)-(6)]. Holland further teaches: “adjusting or depressing each data point along OTDR trace 155 by the Raman gain G (dB) divided by the corresponding distance Z along the fiber 105 yields OTDR trace 160.... Hence, this ‘out-of-band’ offsetting cancels the effects of the Raman non-linearities.” [Holland, col. 7; FIG. 4].
Rad independently teaches the stored algorithm form and the same OFF/ON calculation. Rad states that the Raman/OTDR algorithms may be implemented as “machine-readable instruction code stored on a non-transitory machine-readable storage medium for controlling a suitable processor to execute the algorithm.” [Rad, ¶¶ [0041], [0045]]. Rad also teaches deriving a reference trace with Raman amplification OFF and an in-service trace with Raman amplification ON at the same OTDR pulse wavelength and calculating the cumulative Raman gain profile from the two traces. [Rad, ¶ [0042]; FIGS. 2-3D].
Thus, the combined Li/Holland/Rad teachings supply both portions of claim 12: (1) the complete OTDR correction algorithm using separate fiber-loss and SRS/Raman parameters, and (2) storage of the executable instructions on a non-transitory computer-readable medium.
One of ordinary skill in the art would have been motivated to store the Li/Holland/Rad correction algorithm on the expressly disclosed non-transitory medium because the algorithm is numerical, repeatable, and processor-executed and requires persistent instructions and stored trace/parameter data. Storing such instructions is the conventional and expressly suggested implementation of the same correction method and yields the predictable result of allowing the processor to execute the method whenever OTDR correction is requested. Therefore, claim 12 would have been obvious.
Claims 2, 4, 13, and 15 are rejected under 35 U.S.C. § 103 as being unpatentable over Li et al. in view of Holland and Rad et al., and further in view of Buset et al. (US20200153502A1).
Claim 2
With respect to claim 2, all limitations of claim 1 are taught by Li, Holland, and Rad as set forth above, except wherein claim 2 further requires acquiring optical-power data from a plurality of optical-power monitoring points preset on the OTN, determining from that data whether the service-power distribution of the OTN has changed, and updating the SRS transfer coefficient in response to the detected change.
Li itself teaches that the SRS transfer depends on the current service-light power distribution and deliberately changes that distribution for measurement. Li teaches: “the first service light and the second service light may be obtained by adjusting the optical power of the service
light in the optical network system.... [B]efore calculating the magnitude of the first SRS energy transfer, the first OTDR test curve corresponding to the first service light and the second OTDR test curve corresponding to the second service light need to be measured respectively.” [Li, translated p. 13].
Buset supplies the express network telemetry from multiple power-monitoring points. Buset states: “receiving DAMP information ... includes receiving ... network data including, for example: channel loading, including channel location within the spectrum and channel power for each channel, ASE loading, ASE accumulation to the previous nodes, C-Band power target, L-Band power target, signal power at a previous node, or any combination thereof.... Local data may also include photodiode values and estimated ASE.” [Buset, ¶¶ [0060]-[0061]].
Buset also expressly recognizes service-band loading changes and responds to those changes: “the node 100a recognizes that a fault event has occurred when it identifies a C-Band or L-Band loading change that is a loss of a band.... Upon recognizing that the fault event has occurred, the node 100a adjusts local gain settings and local tilt settings to account for the transient tilt and transient gain.” [Buset, ¶ [0063]]. This teaching establishes detection of a changed optical-service-power distribution using monitored band/channel power information.
Rad supplies the recited update of the SRS/Raman correction parameter once the operating condition changes. Rad teaches: “Once the optical link has entered service, real-time OTDR data can be obtained.... The filtered data can then be used, in conjunction with the reference OTDR power level ... to calculate the real-time Raman gain profile G(Z).... [I]f the difference
between the reference and real-time Raman gain values ... is equal to or greater than the threshold value ... the real-time Raman gain profile G(Z) can be re-calculated ... before evaluating the real-time OTDR trace information.” [Rad, ¶¶ [0048]-[0049]].
One of ordinary skill in the art would have been motivated to combine Buset with Li/Holland/Rad because Li and Holland make the SRS correction expressly dependent on optical power, wavelength loading, and Raman gain, while Buset provides the ordinary OTN telemetry that reveals whether those input conditions have changed.
Once Buset's monitored data indicates a changed channel/band power distribution, Rad's real-time recalculation is the predictable way to update the stored SRS/Raman transfer parameter
rather than continue applying a coefficient calculated for an obsolete power distribution. This combination preserves the accuracy of the corrected OTDR trace and uses each reference for its established function.
Therefore, claim 2 would have been obvious.
Claim 4
With respect to claim 4, all limitations of claim 2 are taught by Li, Holland, Rad, and Buset as set forth above, except wherein claim 4 further requires acquiring a third OTDR trace in the enabled-service state, determining an SRS transfer correction coefficient from the first and third OTDR traces, and updating the SRS transfer coefficient according to that correction coefficient.
For purposes of this prior-art rejection only, and without withdrawing the rejection under 35 U.S.C. § 112(b), the recited “SRS transition coefficient” and “SRS transition correction coefficient” are interpreted as referring to the previously introduced SRS transfer coefficient and SRS transfer correction coefficient, respectively.
Li expressly contemplates a third measurement and pairwise comparison of multiple OTDR traces: “this application may also use three different service light situations as an example to perform OTDR measurement.... [I]t is necessary to measure three OTDR test curves at this time, and compare the three measurement results in pairs to determine the proportional relationship and difference relationship of the three service light energies, and then restore trace0.” [Li, translated p. 15].
Rad expressly teaches generating a baseline Raman profile, generating a later real-time profile, comparing those profiles, calculating an incremental correction, and then estimating the current loss profile: “the reference and real-time Raman gain profiles ... are compared. This comparison may be used to identify changes in the optical characteristics of the optical link ... since the reference Raman gain profile was generated.... Then, the incremental Raman gain profile ... is calculated ... [and] the loss/attenuation profile of the link can then be estimated.” [Rad, ¶ [0051]; FIG. 5].
Accordingly, Li teaches the claimed third trace and pairwise comparison, while Rad teaches using the difference between the original/reference and current Raman profiles as an incremental correction that updates the current Raman/SRS model.
In the claimed terminology, the difference obtained from the first and third traces is the SRS transfer correction coefficient, and applying that correction to the stored SRS transfer coefficient is the same update operation taught by Rad.
One of ordinary skill in the art would have been motivated to acquire the third enabled-service trace after Buset detects a changed service-power distribution because the Raman/SRS coefficient is power-dependent. A coefficient derived under the former loading condition would no longer accurately represent the current link. Li's pairwise third-trace technique and Rad's incremental-profile recalculation provide a direct, predictable mechanism for replacing or correcting the stale coefficient without re-characterizing unrelated parameters. Therefore, claim 4 would have been obvious.
Claim 13
With respect to claim 13, all limitations of claim 11 are taught by Li, Holland, and Rad as set forth above, except wherein claim 13 further requires, before acquiring the OTDR test wavelength, acquiring optical-power data from a plurality of preset OTN monitoring points, determining from that data whether the service-power distribution has changed, and updating the SRS transfer coefficient in response to the detected change.
Li expressly teaches that the SRS transfer is dependent on the service-light power distribution and that different service-light powers are used to obtain different OTDR traces: “the first service light and the second service light may be obtained by adjusting the optical power of the service light in the optical network system.... [B]efore calculating the magnitude of the
first SRS energy transfer, the first OTDR test curve corresponding to the first service light and the second OTDR test curve corresponding to the second service light need to be measured respectively.” [Li, translated p. 13].
Buset provides the claimed plurality of optical-power-monitoring data in an OTN/WDM environment. Buset teaches receiving “channel loading, including channel location within the spectrum and channel power for each channel, ASE loading, ASE accumulation to the previous nodes, C-Band power target, L-Band power target, signal power at a previous node, or any combination thereof,” and further states that local data may include “photodiode values and estimated ASE.” [Buset, ¶¶ [0060]-[0061]].
Buset expressly uses this monitored information to recognize a service-band loading change: “the node 100a recognizes that a fault event has occurred when it identifies a C-Band or L-Band loading change that is a loss of a band.... Upon recognizing that the fault event has occurred, the node 100a adjusts local gain settings and local tilt settings to account for the transient tilt and transient gain.” [Buset, ¶ [0063]].
Rad supplies the required recalculation/update of the Raman/SRS parameter after a change. Rad teaches calculating a real-time Raman gain profile from current OTDR data and the reference level and, when the difference between reference and current Raman gain exceeds the selected threshold, “the real-time Raman gain profile G(Z) can be re-calculated ... before evaluating the real-time OTDR trace information.” [Rad, ¶¶ [0048]-[0049]].
Li's processor 2010 and memory 2030, discussed for claim 11, provide the electronic-device implementation for storing the monitored power data, comparing current and prior operating conditions, and executing the coefficient update. [Li, translated p. 17; FIG. 10].
One of ordinary skill in the art would have been motivated to cause Li's processor to receive Buset's existing power-monitor telemetry and trigger Rad's recalculation when loading changes because Raman transfer depends directly on the service-signal powers. Performing the update before generating the requested OTDR test trace ensures that the processor uses a coefficient corresponding to the current OTN loading rather than stale calibration data. This is a predictable software/control integration of known OTN telemetry with known real-time Raman recalculation and therefore renders claim 13 obvious.
Claim 15
With respect to claim 15, all limitations of claim 13 are taught by Li, Holland, Rad, and Buset as set forth above, except wherein claim 15 further requires acquiring a third OTDR trace with the service wavelength enabled, determining an SRS transfer correction coefficient from the first and third traces, and updating the SRS transfer coefficient according to that correction coefficient.
For purposes of this prior-art rejection only, and without withdrawing the rejection under 35 U.S.C. § 112(b), the recited “SRS transition coefficient” and “SRS transition correction coefficient” are interpreted as referring to the previously introduced SRS transfer coefficient and SRS transfer correction coefficient, respectively.
Li expressly teaches use of a third OTDR measurement and pairwise comparison: “this application may also use three different service light situations as an example to perform OTDR measurement.... [I]t is necessary to measure three OTDR test curves at this time, and compare the three measurement results in pairs to determine the proportional relationship and difference relationship of the three service light energies, and then restore trace0.” [Li, translated p. 15].
Rad expressly teaches using a later current profile to obtain the correction to the stored/reference Raman profile: “the reference and real-time Raman gain profiles ... are compared. This comparison may be used to identify changes in the optical characteristics of the optical link ... since the reference Raman gain profile was generated.... Then, the incremental Raman gain profile ... is calculated....” [Rad, ¶ [0051]; FIG. 5].
The first OTDR trace therefore supplies the stored baseline, the third enabled-service trace supplies the new operating-condition measurement after Buset detects a power-distribution change, and the difference/incremental Raman profile supplies the claimed SRS transfer correction coefficient. Applying the incremental correction to the stored SRS transfer parameter is the update operation required by claim 15.
Li additionally teaches the processor 2010 executing instructions stored in memory 2030, so the third-trace acquisition, pairwise calculation, storage of the correction coefficient, and update of the SRS transfer coefficient are performed in the recited electronic device. [Li, translated p. 17; FIG. 10].
One of ordinary skill in the art would have been motivated to perform this update immediately after the monitored service-power distribution changes because SRS/Raman gain is power dependent. Reusing the old coefficient would knowingly introduce the same SRS measurement error that Li, Holland, and Rad are designed to remove. Acquiring a new trace and applying the incremental correction is therefore the predictable way to maintain a current coefficient while leaving the independently determined fiber-loss coefficient unchanged. Therefore, claim 15 would have been obvious.
Claims 3 and 14 are rejected under 35 U.S.C. § 103 as being unpatentable over Li et al. in view of Holland, Rad et al., and Buset et al., and further in view of Ito et al. (US20100226644A1).
Claim 3
With respect to claim 3, all limitations of claim 2 are taught by Li, Holland, Rad, and Buset as set forth above, except wherein claim 3 further requires the particular six-monitor topology and staged decision sequence: first and second monitoring points at the head-end and tail-end optical bandwidth multiplexers; third/fourth points at head/tail amplifiers of a first service band; fifth/sixth points at head/tail amplifiers of a second service band; periodic endpoint loss calculation; comparison with a preset loss threshold; comparison of current and previous first-monitor data; and, when that data is unchanged, comparison of current and previous head-to-tail differences for the two service bands.
Ito expressly teaches the first/second endpoint monitoring operation and the periodic loss calculation. Ito states: “The present invention utilizes power measurements associated with an optical supervisory channel (OSC) at both ends of a fiber span. These measurements are periodically sampled taking into account propagation delay along the fiber span. Further, these measurements are integrated or time-averaged to account for temporary fluctuations.” [Ito, Abstract; FIGS. 1-2].
Ito further recites: “sampling power measurements at a transmit point at a predetermined time; sampling power measurements at a receive point at the predetermined time plus a time delay, wherein the transmit point and the receive point define endpoints of the fiber optic span; calculating fiber span loss for the predetermined time responsive to the sampled power measurements at the transmit point and at the receive point; repeating the sampling steps and the calculating step; and integrating the calculated fiber span losses.” [Ito, ¶ [0008]; claims 1 and 11; FIG. 2]. Ito also stores the calculated losses over time and uses the stored values to characterize degradation and aging. [Ito, ¶¶ [0048]-[0053]; FIG. 10].
Buset supplies the four additional band-specific monitoring locations. For a C+L-band amplifier structure, Buset teaches: “the first transmission signal, having a C-Band portion and an L-Band portion ... [is] sampled by a first photodiode 106.... [T]he L-Band portion, split ... by a C+L Band WDM filter 109, [is] sampled by a second photodiode 110, amplified by an L-Band erbium amplifier 111 ... and sampled by an L-Band amplifier output photodiode 103.... [T]he C-Band portion passes through a C-Band erbium amplifier 115 and arrives at the third photodiode 114.” [Buset, ¶ [0052]; FIG. 3A].
Buset expressly places analogous processing at network ends, stating that the relevant operations may be performed “at a head end ROADM 42 or a tail end ROADM 42.” [Buset, ¶ [0069]]. Buset also teaches independent C-band and L-band monitoring: “The hybrid C-Band card 108 has a third photodiode 114 for monitoring both the C-Band and the L-Band independently.... The L-Band card 112 has the L-Band amplifier output photodiode 103 configured to monitor the L-Band power level after the L-Band is amplified....” [Buset, ¶ [0064]].
For the current-period/previous-period comparisons, Buset expressly discloses measurements at different times: “FIG. 8A ... depict[s] power level of the signal at differing wavelengths at a first instance in time.... FIG. 8B ... depict[s] power level of the signal at differing wavelengths at a second instance in time, the second instance in time being after the first instance in time.... [The spectrum is] sectioned into a C-Band 262 and an L-Band 266.” [Buset, ¶ [0076]; FIGS. 8A-8B]. Thus, Buset supplies time-separated band-power data from which the claimed first and second band differences are directly obtained.
Using Ito's transmit/receive endpoint powers as the first and second monitoring points and Buset's C-band/L-band photodiode points at corresponding head/tail amplifier locations provides the claimed six monitored quantities. The claimed data differences are the ordinary head-to-tail power differences for each band, and comparing those differences between successive periods is the direct mathematical comparison of Buset's time-separated monitored values.
One of ordinary skill in the art would have been motivated to implement the claimed staged logic because the references identify two different physical causes of OTDR drift that should not be conflated: a true span-loss change and a service-power/Raman-loading change. Ito provides the total-span loss diagnostic. If that loss is below the loss threshold, Buset's per-band telemetry provides the next diagnostic level for deciding whether the service-power distribution changed. This sequence avoids unnecessary recalibration of the fiber-loss coefficient when only service loading changed, and avoids unnecessary recalibration of the SRS coefficient when the physical fiber loss changed. The monitoring points are predictable because head/tail WDM/ROADM and amplifier input/output locations directly expose the total span loss and per-band gain/loss.
Therefore, claim 3 would have been obvious.
Claim 14
With respect to claim 14, all limitations of claim 13 are taught by Li, Holland, Rad, and Buset as set forth above, except wherein claim 14 further requires the specific six-monitor arrangement and the staged current-period/previous-period decision process recited for those monitoring points.
Ito expressly teaches the periodic first/second endpoint monitoring used to determine current span loss. Ito states: “The present invention utilizes power measurements associated with an optical supervisory channel (OSC) at both ends of a fiber span. These measurements are periodically sampled taking into account propagation delay along the fiber span. Further,
these measurements are integrated or time-averaged to account for temporary fluctuations.” [Ito, Abstract; FIGS. 1-2].
Ito further recites sampling power at transmit and receive endpoints, calculating fiber span loss from those values, repeating the measurements, and integrating the calculated loss. [Ito, ¶ [0008]; claims 1 and 11].
Buset supplies the first-service-band and second-service-band monitoring points. Buset teaches that in a C+L-band amplifier the signal is sampled by photodiodes before and after separation/amplification of the C- and L-band portions, including an L-band amplifier output photodiode and a C-band monitoring photodiode. [Buset, ¶ [0052]; FIG. 3A]. Buset further teaches independent C-band and L-band monitoring and states that the relevant operations may be performed “at a head end ROADM 42 or a tail end ROADM 42.” [Buset, ¶¶ [0064], [0069]].
Buset also supplies the time-separated comparison required by claim 14: “FIG. 8A ... depict[s] power level of the signal at differing wavelengths at a first instance in time.... FIG. 8B ... depict[s] power level of the signal at differing wavelengths at a second instance in time, the second instance in time being after the first instance in time.... [The spectrum is] sectioned into a C-Band 262 and an L-Band 266.” [Buset, ¶ [0076]; FIGS. 8A-8B].
Accordingly, Ito's paired endpoint powers map to the first and second monitoring data and current additional-loss determination.
Buset's C-band and L-band photodiode values at head/tail network nodes map to the third through sixth monitoring data.
Subtracting the corresponding head/tail values yields the claimed first and second data differences and comparing the measurements at the first and second time instances yields the claimed current-period/previous-period comparisons.
Li's processor/memory implementation expressly executes stored instructions and therefore provides the claimed electronic-device execution of these measurements and comparisons. [Li, translated p. 17; FIG. 10].
One of ordinary skill in the art would have been motivated to program Li's processor to perform this staged diagnostic sequence because it efficiently distinguishes a true physical span-loss change from a service-band power-distribution change.
The endpoint loss test of Ito is performed first; if it does not show a material fiber-loss event, the processor examines Buset's band-specific power telemetry to determine whether C-band or L-band loading changed.
This avoids updating the wrong decoupled parameter and produces the predictable diagnostic benefit sought by the combined references.
Therefore, claim 14 would have been obvious.
Claims 5, 8, 16, and 19 are rejected under 35 U.S.C. § 103 as being unpatentable over Li et al. in view of Holland and Rad et al., and further in view of Ito et al. and Rapp (US20200049587A1).
Claim 5
With respect to claim 5, all limitations of claim 1 are taught by Li, Holland, and Rad as set forth above, except wherein claim 5 further requires acquiring optical-power data from preset
monitoring points, determining from that data whether a fiber loss exists, and updating the fiber-loss coefficient in response to the detected fiber loss.
Ito expressly teaches repeatedly acquiring endpoint power data and calculating current fiber-span loss. Ito teaches: “sampling power measurements at a transmit point at a predetermined time; sampling power measurements at a receive point at the predetermined time plus a time delay ... calculating fiber span loss ... repeating the sampling steps and the calculating step; and integrating the calculated fiber span losses.” [Ito, ¶ [0008]; claims 1 and 11; FIG. 2].
Ito further teaches using the calculated loss information to detect a real fiber change: “detection of unwelcome fiber taps or fiber degradation could be done through embedding the loss information calculated by the span loss calculation algorithm ... into span management software.... If the change in span loss exceeds a pre-set threshold, an (optional) alarm could be displayed.... After any fiber maintenance ... there will need to be a mechanism to reset the loss tracking on all affected spans.” [Ito, ¶¶ [0048]-[0050]].
Rapp expressly teaches separating Raman-related effects from the physical attenuation and determining the actual fiber loss: “an estimate for the actual loss experienced by a lightwave propagating within the optical fiber can be obtained from the total loss apparent from the OTDR trace and the fitting parameter used to fit the mathematical model ... to the measurement data.” [Rapp, ¶ [0102]; FIG. 9].
Rad likewise teaches recalculating the physical loss/attenuation profile after obtaining the current Raman information: “the incremental Raman gain profile ... is calculated ... [and] the
loss/attenuation profile of the link can then be estimated ... by taking the natural logarithm of the incremental Raman gain profile.” [Rad, ¶ [0051]; FIG. 5].
One of ordinary skill in the art would have been motivated to use Ito's monitored endpoint powers to determine whether a physical fiber-loss change occurred and, when one is detected, to update the fiber-loss coefficient using the current attenuation determination of Rapp/Rad. Continuing to use the pre-change coefficient after aging, a bend, splice change, tap, or other physical loss event would produce an incorrect decoupling equation and an incorrect corrected OTDR trace.
Updating that coefficient is therefore the predictable maintenance step necessary to preserve the accuracy sought by all of the references.
Therefore, claim 5 would have been obvious.
Claim 8
With respect to claim 8, all limitations of claim 5 are taught by Li, Holland, Rad, Ito, and Rapp as set forth above, except wherein claim 8 further requires acquiring a third OTDR trace in the enabled-service state, determining a fiber-loss correction coefficient according to the third OTDR trace and the SRS transfer coefficient, and updating the fiber-loss coefficient according to the fiber-loss correction coefficient.
Li expressly contemplates obtaining more than two current traces and comparing them to update the correction: “this application may also use three different service light situations as an example to perform OTDR measurement.... [I]t is necessary to measure three OTDR test
curves at this time, and compare the three measurement results in pairs....” [Li, translated p. 15].
Rapp supplies the claimed separation of the current trace into Raman/SRS and actual-loss components on a segment-by-segment basis: “The Raman gain ... experienced by the probe pulses within the respective segments of the fiber optic transmission system can be determined from the OTDR trace ... by subtracting [a virtual] OTDR trace ... that would be obtained for the respective segments without any Raman gain.... [The] virtual OTDR traces ... can be constructed ... assuming exponential decay with the fiber attenuation coefficient derived from [another] OTDR trace.” [Rapp, ¶¶ [0097]-[0098]; FIG. 9].
Rapp then teaches: “the actual loss ... can be obtained from the total loss apparent from the OTDR trace and the fitting parameter used to fit the mathematical model ... to the measurement data.” [Rapp, ¶ [0102]]. Rad independently teaches deriving a current
loss/attenuation profile after calculating the current/incremental Raman profile. [Rad, ¶ [0051]; FIG. 5].
These teachings correspond directly to the claimed third-trace update. The third/current OTDR trace contains both physical attenuation and the SRS contribution; the already determined SRS/Raman parameter is used to remove the SRS portion; the residual difference represents the correction to actual fiber loss; and that result is used to update the stored attenuation/fiber-loss coefficient.
One of ordinary skill in the art would have been motivated to perform this recalculation after Ito's monitored endpoint powers indicate a new physical span loss. A third current trace captures the changed physical link, while retaining the SRS parameter permits the two effects to remain decoupled. Updating only the fiber-loss coefficient with the residual physical-loss correction is the predictable way to maintain the accuracy of the parameter-decoupling model without incorrectly attributing a physical aging/bend/splice loss to Raman transfer.
Therefore, claim 8 would have been obvious.
Claim 16
With respect to claim 16, all limitations of claim 11 are taught by Li, Holland, and Rad as set forth above, except wherein claim 16 further requires acquiring optical-power data from preset OTN monitoring points, determining whether a fiber loss exists in the optical-fiber transmission system, and updating the fiber-loss coefficient when such loss exists.
Ito expressly teaches the monitoring and physical-loss detection.
Ito teaches periodic transmit/receive power measurements at the two ends of a fiber span and calculation of span loss from those powers. [Ito, ¶¶ [0007]-[0008]; FIGS. 1-2].
Ito further teaches using the calculated loss information for “the detection of fiber degradation” and states that if “the change in span loss exceeds a pre-set threshold, an (optional) alarm could be displayed.” [Ito, ¶¶ [0049]-[0050]].
Rapp teaches recalculating the actual fiber loss after separating the Raman contribution: “an estimate for the actual loss experienced by a lightwave propagating within the optical fiber
can be obtained from the total loss apparent from the OTDR trace and the fitting parameter used to fit the mathematical model ... to the measurement data.” [Rapp, ¶ [0102]; FIG. 9].
Rad similarly teaches that after the incremental Raman gain is determined, “the loss/attenuation profile of the link can then be estimated.” [Rad, ¶ [0051]; FIG. 5]. These calculations provide the updated fiber-loss coefficient/profile required after the physical loss is detected.
Li's processor 2010 and memory 2030 expressly execute stored measurement/correction instructions and therefore provide the recited electronic-device implementation for receiving the monitored powers, determining whether loss exists, recalculating the loss coefficient, and storing the updated value. [Li, translated p. 17; FIG. 10].
One of ordinary skill in the art would have been motivated to program the processor to update the stored fiber-loss coefficient after Ito detects a new physical loss because the coefficient is an input to the decoupling/correction equation.
A stale attenuation coefficient would cause both the calculated Raman contribution and the corrected OTDR trace to be wrong.
Rapp and Rad provide the known calculation for isolating current physical attenuation from Raman effects, so using those calculations to update Li's stored coefficient is the predictable maintenance operation.
Therefore, claim 16 would have been obvious.
Claim 19
With respect to claim 19, all limitations of claim 16 are taught by Li, Holland, Rad, Ito, and Rapp as set forth above, except wherein claim 19 further requires acquiring a third enabled-service OTDR trace, determining a fiber-loss correction coefficient according to the third trace and the SRS transfer coefficient, and updating the fiber-loss coefficient according to that correction coefficient.
Li expressly teaches acquiring more than two OTDR traces and comparing the additional trace measurements in pairs: “this application may also use three different service light situations as an example to perform OTDR measurement.... [I]t is necessary to measure three OTDR test curves at this time, and compare the three measurement results in pairs....” [Li, translated p. 15]. This supplies the claimed later/current third measurement.
Rapp teaches using the current OTDR trace together with Raman information and the attenuation model to isolate actual fiber loss.
Rapp states: “The Raman gain ... experienced by the probe pulses within the respective segments ... can be determined from the OTDR trace ... by subtracting [a virtual] OTDR trace ... that would be obtained for the respective segments without any Raman gain.” [Rapp, ¶¶ [0097]-[0098]; FIG. 9]. Rapp further teaches that “the actual loss ... can be obtained from the total loss apparent from the OTDR trace and the fitting parameter used to fit the mathematical model ... to the measurement data.” [Rapp, ¶ [0102]].
Rad independently teaches deriving a current loss/attenuation profile after calculating the current/incremental Raman profile: “the incremental Raman gain profile ... is calculated ... [and] the loss/attenuation profile of the link can then be estimated.” [Rad, ¶ [0051]; FIG. 5].
Accordingly, the third/current trace contains the present total measured loss; the stored SRS transfer coefficient/Raman profile identifies the nonlinear portion; removing that portion yields the physical-loss correction; and applying the correction updates the stored fiber-loss coefficient.
This is the exact functional relationship required by claim 19.
Li's processor 2010 and memory 2030 provide the electronic implementation for storing the original coefficients, receiving the third trace, calculating the correction coefficient, and overwriting/updating the stored fiber-loss coefficient. [Li, translated p. 17; FIG. 10].
One of ordinary skill would have been motivated to perform this calculation after the monitoring logic of claim 16 determines that a real physical loss exists.
A current third trace is needed to quantify the new state of the fiber; using the already known SRS parameter prevents the nonlinear contribution from being misclassified as physical loss;
and updating the attenuation coefficient makes subsequent corrected OTDR traces correspond to the changed fiber. The combination therefore uses known measurements for their established purposes and yields the predictable updated model. Therefore, claim 19 would have been obvious.
Claims 6 and 17 are rejected under 35 U.S.C. § 103 as being unpatentable over Li et al. in view of Holland, Rad et al., Ito et al., and Rapp, and further in view of Xia et al. (US20110123190A1).
Claim 6
With respect to claim 6, all limitations of claim 5 are taught by Li, Holland, Rad, Ito, and Rapp as set forth above, except wherein claim 6 further specifies that the first and second monitoring points are respectively arranged at opposite head-end and tail-end optical bandwidth multiplexers, that the two power values are periodically acquired to determine a current additional-loss value, and that fiber loss is determined to exist when the additional-loss value exceeds a preset loss threshold.
Ito supplies the periodic endpoint measurement and span-loss calculation. Ito's system requests “a power measurement at a transmit point at a predetermined time” and “a power measurement at a receive point at the predetermined time plus a time delay, wherein the transmit point and the receive point define endpoints of the fiber optic span,” and then
“calculate[s] fiber span loss ... responsive to the requested power measurements.” [Ito, claim 11; FIGS. 1-2].
Ito further teaches that the power measurements may be OSC powers added at the transmit point and removed at the receive point. [Ito, claims 5-6, 13-14].
Xia expressly teaches determining optical loss from two monitored endpoint powers and comparing that loss with a threshold. Xia states: “fiber taps may be installed proximate ... to the optical transmitter and the optical receiver.... According to an exemplary process ... the fiber taps may permit the photodetector to measure optical power and/or optical power connection loss between the optical transmitter and the optical receiver. The optical power loss may be compared to an optical power loss threshold value or a range of optical power loss values to determine whether the optical power loss is an acceptable value.” [Xia, ¶¶ [0008]-[0014]; FIGS. 1A-1D].
Xia further claims a system configured to “measure a first optical power at the first fiber tap; measure a second optical power at the second fiber tap; and determine an optical power loss based on the first optical power and the second optical power” and then “compare the optical power loss to an optical power loss threshold value or a range of optical power loss values.” [Xia, claims 14 and 19].
Thus, Ito teaches the claimed periodic first/second monitoring data and calculation of the current span/additional loss, while Xia supplies the express threshold comparison and loss determination. Locating these monitors at the head-end and tail-end optical bandwidth multiplexers would have been a predictable implementation because those multiplexers are
the ingress and egress boundaries of the OTN span whose aggregate optical loss is being monitored; measuring immediately at those boundaries directly captures the intervening span loss.
One of ordinary skill in the art would have been motivated to use Xia's loss-threshold test on Ito's periodically calculated head-to-tail loss so that minor measurement fluctuation does not trigger a fiber-loss update while a material excess loss does. This produces the predictable automated decision expressly sought by both references and provides the trigger for the coefficient update of claim 5. Therefore, claim 6 would have been obvious.
Claim 17
With respect to claim 17, all limitations of claim 16 are taught by Li, Holland, Rad, Ito, and Rapp as set forth above, except wherein claim 17 further requires first and second monitoring points at the head-end and tail-end optical bandwidth multiplexers, periodic acquisition of their monitoring data, determination of a current additional-loss value from those data, and determination that fiber loss exists when the additional-loss value is greater than a preset loss threshold.
Ito expressly teaches the endpoint placement/function and periodic loss calculation: the system requests power measurements at “a transmit point” and “a receive point,” expressly defines those points as “endpoints of the fiber optic span,” calculates the fiber span loss from those measurements, stores the calculated loss, and time-averages the current result with stored results. [Ito, claim 11; FIGS. 1-2].
Xia supplies the express threshold determination.
Xia states: “the fiber taps may permit the photodetector to measure optical power and/or optical power connection loss between the optical transmitter and the optical receiver. The optical power loss may be compared to an optical power loss threshold value or a range of optical power loss values to determine whether the optical power loss is an acceptable value.” [Xia, ¶ [0009]; see also ¶¶ [0014]-[0015]].
Xia further claims measurement of “a first optical power at the first fiber tap,” “a second optical power at the second fiber tap,” determination of “an optical power loss based on the first optical power and the second optical power,” and comparison of that loss with “an optical power loss threshold value or a range of optical power loss values.” [Xia, claims 14 and 19].
Locating the two known endpoint monitors on the optical bandwidth multiplexers would have been a predictable implementation because the head and tail multiplexers bound the monitored OTN optical path and thus provide the natural points at which the aggregate transmitted and received powers are available. The difference between the periodic endpoint values is the current additional span loss.
Li's processor/memory architecture provides the electronic execution of the periodic acquisition, subtraction, comparison with the preset threshold, and loss determination. [Li, translated p. 17; FIG. 10].
One of ordinary skill would have been motivated to implement Xia's explicit threshold comparison on Ito's periodically calculated head-to-tail loss in Li's processor so that normal
power fluctuation is ignored but a material additional loss triggers the fiber-loss update of claim 16.
This is the direct automated implementation of the references' monitoring functions and yields the predictable result of current, threshold-based fiber-loss detection. Therefore, claim 17 would have been obvious.
Claims 7 and 18 are rejected under 35 U.S.C. § 103 as being unpatentable over Li et al. in view of Holland, Rad et al., Ito et al., Rapp, and Xia et al., as applied to claims 6 and 17 above, and further in view of Asher et al. (US6674518B1), Takasu et al. (US20220123832A1), and Lovely et al. (US20130188177A1).
Claim 7
With respect to claim 7, all limitations of claim 6 are taught by Li, Holland, Rad, Ito, Rapp, and Xia as set forth above, except wherein claim 7 further requires that the preset loss threshold be the product of an intrinsic optical-fiber loss value and a preset number of threshold exceedances, and, after an exceedance, requires updating the exceedance count and calculating a new loss threshold according to the updated count.
Takasu expressly identifies the intrinsic-loss quantity used as an OTDR decision parameter: “31d: An intrinsic loss threshold value [dB/km] of the optical fiber.” [Takasu, ¶ [0090]; FIG. 4]. Thus, Takasu provides the claimed physical baseline: intrinsic optical-fiber loss expressed as a loss-per-unit-length threshold parameter.
Asher teaches dynamically changing a threshold with reference to the natural loss behavior of the optical fiber rather than treating every departure as a new fault. Asher states: “A filter threshold is continually set to a new level to filter out the positive slope.... The filtered value is based on the total loss of any given fiber-optic cable segment and is computed based on the optical characteristics of the fiber material (e.g. the loss factor due to the optical material of the fiber itself).” [Asher, cols. 7-8; FIG. 5].
Lovely expressly teaches using the number of threshold exceedances as a monitoring criterion: “The criteria may take a variety of forms ... such criteria as change-space distance thresholds, spectral power thresholds, numbers of times thresholds are exceeded in a specified time interval, and so on, that will distinguish between disturbances that should be reported and those that should not.” [Lovely, ¶ [0044]].
Lovely further teaches automatic updating of the threshold criteria based on accumulated operating history: “The preset thresholds etc. might be updated by the user, or automatically by the processing unit, based upon actual usage over a period of time with and without real reportable disturbances occurring.” [Lovely, ¶ [0131]].
The added references therefore provide each variable and control relationship recited in claim 7: Takasu provides an intrinsic fiber-loss threshold quantity; Lovely makes the number of threshold exceedances an express decision variable and teaches updating thresholds based on operating history; and Asher teaches changing the threshold level according to the fiber's natural/material loss behavior.
The claimed multiplication uses the intrinsic-loss quantity as the unit increment and the dimensionless exceedance count as the scale factor. The first threshold corresponds to one intrinsic-loss unit, the next to two units after the count is incremented, and so forth.
One of ordinary skill in the art would have been motivated to use this stepwise product in the combined monitoring system because repeated exceedances after an acknowledged loss/aging change indicate that the operating baseline has shifted. Incrementing the exceedance count and recomputing the threshold in integral multiples of the known intrinsic-loss scale avoids repeatedly reporting the same accepted baseline change while retaining a threshold tied to the actual physical loss characteristic of the fiber. Multiplication of a known physical baseline by a known count is routine arithmetic that predictably implements the adaptive-threshold teachings of Asher and Lovely without altering their principle of operation.
Therefore, claim 7 would have been obvious.
Claim 18
With respect to claim 18, all limitations of claim 17 are taught by Li, Holland, Rad, Ito, Rapp, and Xia as set forth above, except wherein claim 18 further requires the preset loss threshold to equal an intrinsic fiber-loss value multiplied by a preset number of threshold exceedances, and, after an exceedance, requires updating that exceedance count and calculating a new loss threshold according to the updated count.
Takasu expressly discloses the intrinsic-loss threshold variable used in OTDR event/loss determination: “31d: An intrinsic loss threshold value [dB/km] of the optical fiber.” [Takasu, ¶ [0090]; FIG. 4].
Asher teaches dynamically resetting a threshold based on the optical material's natural loss: “A filter threshold is continually set to a new level to filter out the positive slope.... The filtered value is based on the total loss of any given fiber-optic cable segment and is computed based on the optical characteristics of the fiber material (e.g. the loss factor due to the optical material of the fiber itself).” [Asher, cols. 7-8; FIG. 5].
Lovely expressly teaches using threshold-exceedance counts as part of the decision criteria: “The criteria may take a variety of forms ... such criteria as change-space distance thresholds, spectral power thresholds, numbers of times thresholds are exceeded in a specified time interval, and so on, that will distinguish between disturbances that should be reported and those that should not.” [Lovely, ¶ [0044]].
Lovely also teaches automatically updating the threshold criteria from accumulated operating history: “The preset thresholds etc. might be updated by the user, or automatically by the processing unit, based upon actual usage over a period of time with and without real reportable disturbances occurring.” [Lovely, ¶ [0131]].
These teachings provide the variables and update mechanism of claim 18. Takasu supplies the intrinsic-loss unit; Lovely supplies the exceedance count and automatic updating; and Asher supplies adjustment of the threshold according to the fiber's natural loss characteristic.
Multiplying the intrinsic-loss unit by the integer exceedance count is the straightforward stepwise scaling of the physical baseline: one unit for the first threshold, two units after the first count update, and so forth.
Li's processor and memory provide the recited implementation for retaining the current exceedance count, incrementing it after the threshold is exceeded, recomputing the loss threshold, and using the new threshold during the next monitoring period. [Li, translated p. 17; FIG. 10].
One of ordinary skill would have been motivated to implement this stepwise scaling because the combined system already distinguishes a persistent physical-loss change from temporary fluctuation.
After an acknowledged exceedance shifts the operating baseline, increasing the threshold in known intrinsic-loss increments prevents repeated alarms for the same accepted change while preserving a physically meaningful threshold.
The calculation is routine arithmetic on known monitoring variables and predictably implements the adaptive-threshold teachings.
Therefore, claim 18 would have been obvious.
Claims 9 and 20 are rejected under 35 U.S.C. § 103 as being unpatentable over Li et al. in view of Holland and Rad et al., and further in view of Rapp, Bonche et al. (US20180372581A1), and Rohde (EP 2 549 665 A1).
Claim 9
With respect to claim 9, all limitations of claim 1 are taught by Li, Holland, and Rad as set forth above, except wherein claim 9 further requires discretizing the optical fiber transmission system into a plurality of fiber segments, determining OTDR discrete traces for those segments according to the fiber-loss coefficient and SRS transfer coefficient, and performing interpolation and integration processing on the discrete traces to determine the final OTDR test trace.
Rapp expressly divides the optical link into discrete segments and analyzes them separately: “the fiber optic transmission system is split into two segments that are considered separately.... The first segment 450 extends from an input of the fiber optic transmission system to the location 14 of the considered event and the second segment 452 ranges from location 14 to an end of the fiber optical transmission system.” [Rapp, ¶ [0097]; FIG. 9].
Rapp further teaches constructing a modeled/virtual trace for the respective segments using both attenuation and Raman information: “The Raman gain ... experienced by the probe pulses within the respective segments ... can be determined from the OTDR trace ... by subtracting OTDR trace 400 or OTDR trace 402 that would be obtained for the respective segments without any Raman gain.... The virtual OTDR traces 400 and 402 can be constructed
very easily by starting from the attenuation 410 at the beginning of the respective segment and assuming exponential decay with the fiber attenuation coefficient derived from OTDR trace 30'.” [Rapp, ¶ [0098]; FIG. 9].
Bonche expressly supplies the claimed interpolation processing used to join discrete/selected trace portions: “the time base control unit 108 may generate, based on the analysis of each trace along the DUT, the combined trace that identifies optical events detected along the DUT by interpolating a combined trace section between two non-adjacent combined trace sections of the combined trace to form the combined trace.” [Bonche, ¶ [0083]; FIG. 14]. Bonche further states: “in order to join two different trace sections that are based on two different pulse widths, the interpolation may be based on dedicated algorithms.... [T]he time base control unit 108 may interpolate a combined trace section where no respective trace section is included in the combined trace.” [Bonche, ¶¶ [0083]-[0084]].
Rohde expressly teaches the integration operation by which sampled returned-light strength is converted into the distance-domain OTDR trace: “The strength of the return pulses is measured and integrated as a function of time, and is plotted as a function of fiber length.” [Rohde, ¶ [0003]].
Thus, Rapp supplies discretization and calculation of segment-wise traces using attenuation and Raman/SRS information, Bonche supplies interpolation between discrete trace portions, and Rohde supplies integration of the time-domain return data into the final distance trace. These operations collectively map each recited numerical-processing limitation rather than merely describing a generic OTDR.
One of ordinary skill in the art would have been motivated to combine the teachings because the Li/Holland/Rad coefficient correction is inherently a distance-dependent calculation. Segmenting the link as Rapp teaches permits the local attenuation and Raman contribution to be evaluated over manageable intervals; interpolation as Bonche teaches fills gaps or transitions between separately calculated valid trace sections; and integration as Rohde teaches converts the corrected sampled return values into the continuous OTDR trace. The result is the predictable numerical reconstruction of a corrected trace from coefficient-based segment data.
Therefore, claim 9 would have been obvious.
Claim 20
With respect to claim 20, all limitations of claim 11 are taught by Li, Holland, and Rad as set forth above, except wherein claim 20 further requires discretizing the fiber transmission system into a plurality of segments, determining OTDR discrete traces for the segments according to the fiber-loss coefficient and SRS transfer coefficient, and performing interpolation and integration processing on the discrete traces to determine the OTDR test trace.
Rapp expressly provides the segment-wise numerical construction. Rapp teaches: “the fiber optic transmission system is split into two segments that are considered separately.... The first segment 450 extends from an input of the fiber optic transmission system to the location 14 of the considered event and the second segment 452 ranges from location 14 to an end of the fiber optical transmission system.” [Rapp, ¶ [0097]; FIG. 9].
Rapp then uses attenuation and Raman information to construct the corresponding modeled traces: “The Raman gain ... experienced by the probe pulses within the respective segments ... can be determined from the OTDR trace ... by subtracting OTDR trace 400 or OTDR trace 402 that would be obtained for the respective segments without any Raman gain.... The virtual OTDR traces 400 and 402 can be constructed very easily by starting from the attenuation 410 at the beginning of the respective segment and assuming exponential decay with the fiber attenuation coefficient derived from OTDR trace 30'.” [Rapp, ¶ [0098]; FIG. 9].
Bonche expressly teaches interpolation between discrete trace sections to form a continuous final trace: “the time base control unit 108 may generate ... the combined trace that identifies optical events detected along the DUT by interpolating a combined trace section between two non-adjacent combined trace sections of the combined trace to form the combined trace.” [Bonche, ¶ [0083]; FIG. 14]. Bonche further teaches that dedicated interpolation algorithms may be used where different trace sections do not directly meet. [Bonche, ¶¶ [0083]-[0084]].
Rohde expressly supplies the integration processing: “The strength of the return pulses is measured and integrated as a function of time, and is plotted as a function of fiber length.” [Rohde, ¶ [0003]].
Li's processor/memory architecture expressly executes stored instructions and therefore provides the claimed device for carrying out the segmentation, discrete-trace calculations, interpolation, and integration. [Li, translated p. 17; FIG. 10].
One of ordinary skill in the art would have been motivated to program Li's processor to perform Rapp's segment-wise coefficient calculation, Bonche's interpolation, and Rohde's time-domain integration because the corrected trace must be evaluated over distance and assembled from discrete sampled values. Segmenting the fiber permits local application of the attenuation and SRS coefficients; interpolation provides a continuous transition between separately determined trace portions; and integration converts the corrected sampled return power into the distance-domain OTDR trace.
These are standard, complementary numerical operations and predictably produce the final corrected trace required by claim 20.
Therefore, claim 20 would have been obvious.
Claim 10 is rejected under 35 U.S.C. § 103 as being unpatentable over Li et al. in view of Holland and Rad et al., and further in view of Asher et al., Bonche et al., Yi et al. (US20170180041A1), and Ichimura et al. (JP2005223803A).
Claim 10
With respect to claim 10, all limitations of claim 1 are taught by Li, Holland, and Rad as set forth above, except wherein claim 10 further requires, after the corrected OTDR test trace has been obtained, extracting reflection-event points from that corrected test trace and loading those extracted event points onto the first OTDR trace to obtain a fourth OTDR trace.
Yi expressly teaches identifying and extracting reflection-event locations from OTDR sampling data: “OTDR issuing test light to an optical fiber business link, and receiving reflected light, to form a data curve of reflection sampling points including end event.... [I]f an absolute value of a difference between maximum sampling value ... in the search interval and a sampling value of the starting point ... is greater than a second predetermined threshold value, determining an end event as a reflection end event....” [Yi, ¶ [0011]; claim 1].
Yi further teaches producing event-position information after the extraction: “after completing the search for the end event, outputting and displaying a list of the end events (the list mainly includes an end starting value (km), an end value (km) of the end).” [Yi, ¶ [0030]].
Thus, Yi provides discrete reflection-event points/locations separated from the continuous OTDR background.
Asher teaches expressly removing reflection spikes from the underlying trace and reconstructing the removed portions.
Asher states: “the reflectance Spike is accounted for and removed from the trace pattern.... [P]rior to and during operation of the OTDR the reflectance Spikes are detected and removed.” [Asher, col. 6]. Asher further teaches: “If this is the last data point, the removed data points are interpolated as shown at 518 and the method is completed as shown at 526.” [Asher, col. 8; FIG. 5].
Bonche teaches preserving detected optical events while assembling a composite/combined trace: the system “may generate, based on the analysis of each trace along the DUT, the combined trace that identifies optical events detected along the DUT by interpolating a
combined trace section between two non-adjacent combined trace sections of the combined trace to form the combined trace.” [Bonche, ¶ [0083]; FIG. 14].
Ichimura supplies an additional express trace-synthesis operation in a Raman-amplified OTDR environment: “The synthesizer 154 extracts and synthesizes the correct measurement results of the respective amplification spans from the memories 152a and 152b.... The combined result shows the correct C-OTDR measurement result for each amplification span of the optical transmission line 124.” [Ichimura, translated p. 11].
Together, these references teach the functional sequence required by claim 10: Yi identifies and retains the reflection-event positions; Asher separates the reflectance spikes/events from the continuous loss trace and reconstructs the event-free background; Bonche teaches forming a final event-bearing combined trace from selected trace portions; and Ichimura teaches extracting selected OTDR measurement portions and synthesizing them onto a final combined trace in the same Raman-amplified measurement field.
One of ordinary skill in the art would have been motivated to apply these event-processing teachings to the corrected baseline produced by Li/Holland/Rad because the distributed-loss background and localized reflection events convey different information.
Once the SRS-distorted distributed background is replaced by the corrected first/reference trace, reinserting or “loading” the separately extracted true reflection-event points onto that corrected baseline preserves connector/splice/reflection information while retaining the corrected attenuation background. That is the predictable inverse/compositing operation of Asher's event removal and Bonche/Ichimura's trace synthesis, and it yields the final corrected event-bearing trace required by claim 10.
Therefore, claim 10 would have been obvious.
It is noted that any citations to specific pages, columns, lines, or figures in the prior art references and any interpretation of the reference should not be considered to be limiting in any way. A reference is relevant for all it contains and may be relied upon for all that it would have reasonably suggested to one having ordinary skill in the art. See MPEP § 2123.
Conclusion
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/MOHAMMED ABDELRAHEEM/Examiner, Art Unit 2635
/DAVID C PAYNE/Supervisory Patent Examiner, Art Unit 2635
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