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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 27 February 2026 has been entered.
Response to Amendment and Status of Application
This notice is in response to the amendments filed 27 February 2026. Claims 1-7, 11-15, and 17-22 are pending in the instant application where claims 1, 13, 17, and 20-21 have been amended and claims 8-10 and 16 have been cancelled.
Response to Arguments
Applicant's arguments filed 27 February 2026 have been fully considered but they are not persuasive.
Applicant’s response on page 2 directed to Eiselt is a recitation of what Eiselt teaches and no arguments are put forth related to the rejection of claims 1, 13, and 17. Examiner has recited (and applicant acknowledges) that Eiselt discloses a VOA 4A in the signal path before the photodiode. For this reason, secondary reference Gurusami is used to address adjusting or modifying signal values after the photodiode in the signal path. Arguments put forth against Gurusami are addressed below.
Regarding applicant’s argument (remarks page 5 full paragraph 2 – page 6 paragraph 2) that Gurusami is silent to both “decreasing values of the electrical samples related to the backscatter optical signal…without modifying or adjusting optical values of the sample prior to the samples being sampled…” and “increasing values of the electrical samples related to the backscatter optical signal…without modifying or adjusting the optical values of the sample prior to the samples being sampled…”, examiner notes that Gurusami is not relied upon to teach the increase and decrease of the values of the electrical samples themselves. Instead, Gurusami is relied upon only to teach the presence of electrical signals vs. optical signals, and teaching that any adjustment is made to the electrical samples without first modifying or adjusting the values of the sample prior to the samples being sampled. In light of that, the presence of an amplifier after detection by the photodiode 32 within fig. 1 fulfills this requirement.
Regarding applicant’s argument (remarks page 6 paragraph 3) that while Eiselt discloses adjusting the strength of a signal/sample, it does not disclose adjusting the strength of electrical samples. This newly added limitation is addressed via a revised interpretation of Gurusami below.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
(A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
Regarding claim 13, the claim recites the limitation “a receiver for receiving a backscatter signal” which uses the nonce term “receiver” that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier.
Accordingly, the limitation “receiver” is interpreted under 35 U.S.C. 112(f) as corresponding to a device comprising a light detector 10, a transimpedance amplifier (TIA), and an analog-to-digital converter (ADC) (applicant’s specification [0022]), where the light detector comprises a photodiode or photoconductor (applicant’s specification [0019]).
Regarding claim 17, the claim recites the limitations “means for outputting”, “means for receiving”, “means for determining”, and “means for controlling” that are coupled with functional language without reciting sufficient structure to perform the recited function are not preceded by a structural modifier.
The limitation “means for outputting” is interpreted under 35 U.S.C. 112(f) as corresponding to a laser source (applicant’s specification [0055]).
The limitation “means for receiving” is interpreted under 35 U.S.C. 112(f) as corresponding to a light detector ([0055]), an analog-to-digital converter ([0059]), wherein the light detector may be a photodiode or photodetector ([0019]), or a transimpedance amplifier ([0022]).
The limitation “means for determining” is interpreted under 35 U.S.C. 112(f) as corresponding to a processor ([0055]).
The limitation “means for controlling” is interpreted under 35 U.S.C. 112(f) as also corresponding to a processor ([0055]).
Claim Rejections - 35 USC § 112
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.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 13-15, 17-19, and 21-22 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 13, the claim recites the limitation “without modifying or adjusting optical values of the samples of the received backscatter optical signal” in step (b) line 3. There is insufficient antecedent basis for this limitation in the claim. Examiner notes a similar amendment was made in independent claim 1, where “the samples” was amended to “samples” which does not raise an antecedence issue. Correction is required. Examiner will interpret the limitation such that any samples of the received backscatter optical signal will read on the claim.
Regarding claim 17, the claim recites the limitation “without modifying or adjusting optical values of the samples of the received backscatter optical signal” on line 12. There is insufficient antecedent basis for this limitation in the claim. As noted above, a similar amendment was made in independent claim 1, where “the samples” was amended to “samples” which does not raise an antecedence issue. Correction is required. Examiner will interpret the limitation such that any samples of the received backscatter optical signal will read on the claim.
The claim recites the limitation “the electrical values related to samples of the backscatter signal” on claim 17 page 2 line 7. There is insufficient antecedent basis for this limitation in the claim. Examiner will interpret the limitation such that it corresponds to “the values of the electrical samples related to the optical backscatter signal” disclosed on claim 17 page 2 line 2.
The claim recites the limitation “the receiver” on claim 17 page 2 line 10. There is insufficient antecedent basis for this limitation in the claim. Examiner will interpret the limitation such that “the receiver” corresponds to “the means for receiving” within the claim.
Claims 14-15 and 21 are rejected due to their dependence on the deficiency of claim 13.
Claims 18-19 and 22 are rejected due to their dependence on the deficiency of claim 17.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to 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 later invention.
Claims 1, 5, 11-13, 15, and 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over US 2018/0331756 A1 by Michael Eiselt (herein after “Eiselt”) in view of US 2015/0253217 A1 by Aravanan Gurusami et al. (herein after “Gurusami”).
Regarding claim 1, Eiselt discloses an Optical Time-Domain Reflectometry method (Eiselt abstract/title discloses an optical time-domain reflectometer and method of use), comprising:
(a) outputting, by a laser source of an Optical Time-Domain Reflectometer (OTDR), to an optical fiber, a laser pulse (Eiselt [0004] and fig. 1 disclose an OTDR comprising a laser which generates an optical pulse transmitted into an optical fiber under test (“fiber link under test” or FLUT));
(b) sampling, by a processor of the OTDR from a receiver of the ORTD, samples of a backscatter optical signal generated by the optical fiber in response to the laser pulse of step (a) (Eiselt [0007] discloses that the method comprises measuring a backscattered trace [sampling samples of a backscatter signal] of a FLUT [generated by the optical fiber] in response to an optical test signal [i.e. pulse of step (a)] wherein the backscattered trace is received by a photodiode [a receiver]); [0017] discloses the use of a processor which evaluates the backscatter signal and provides the backscattered trace (see fig. 2));
(c) determining, by the processor, from one or more values of the sample related to the backscatter optical signal sampled in step (b) that at least one element of the receiver is in a saturated operating state (Eiselt [0005] and fig. 2 disclose a typical backscattered trace of a FLUT with dead zones in the trace resulting from the saturation of a photodiode [receiver]; [0011] discloses that an embodiment of the invention comprises a means to adjust and suppress dead zones within the backscattered trace of the FLUT – i.e. a determination is made whether the receiver is in a saturated operating state or not; [0017] discloses that the processor is used to evaluate backscatter traces [including identifying dead zones caused by saturation] – i.e. a determination is made by the processor whether the receiver is in a saturated operating state);
(d) in response to step (c), controlling, by the processor, the receiver to decrease values of the samples related to the backscatter optical signal sampled by the processor to within an unsaturated operating state of the at least one element of the receiver (Eiselt [0019] discloses that the processor may be used to limit the power of the optical signal [values of the samples related to the backscatter optical signal sampled] received by the photodiode [receiver] within a predetermined power range [i.e. limiting the strength/intensity of the signals received by the receiver to within a non-saturated state]; the control by the processor can be in response to an identification of large reflections which result in saturation and dead zones as disclosed in fig. 2 and [0005] – therefore the signal sampled is decreased to within an unsaturated operating state for the receiver; [0039] also explores this (see below); [0045] discloses the suppression of dead zones due to saturation, and [0048] discloses the use of a defined gain variation over time with which to account for the reduction of values sampled by the receiver [i.e. reduce the receiver into an unsaturated operating state]);
(e) determining, by the processor, from one or more values of samples related to the backscatter optical signal sampled after step (d) that the at least one element of the receiver would not be operating in the saturated operating state if the values of samples related to the backscatter optical signal sampled by the processor were increased (Eiselt [0039] discloses the determination of a predetermined power range of signal available to the receiver – a maximum power Pmax is chosen as an upper limit to limit the max power and suppress dead zones, as described in step (d) above; a lower power limit is also chosen Pmin which is set to maintain a minimum signal to noise ratio STNR received by the receiver; for purposes of attenuation, the processor iteratively adjusts the gain of an amplifier (i.e. increasing or decreasing the signal) such that an approximately constant power is seen by the photodiode over time, and the gain can be set/changed in real time based on the strength of the backscatter signals; fig. 5A shows raw data seen by the receiver, fig. 5B shows a gain function applied to ensure the signal strength is between Pmin and Pmax, and fig. 5C shows the approx. constant signal seen by the receiver; a determination is made by the processor to adjust the gain function to ensure a constant signal is seen by the receiver – if that determination was not made, no cause for adjustment would exist and a corresponding change in the gain would not exist; the processor adjusts the gain such that the receiver would not be operating in a saturated operating state in order to maintain the signal shown in fig. 5C, whether the values of the samples related to the backscatter optical signals need to be increased or decreased; both gain increases and decreases are seen in fig. 5B to ensure decreased and increased signal P(t) of fig. 5A respectively); and
(f) in response to step (e), controlling, by the processor, the receiver to increase the values of the samples related to the backscatter optical signal sampled by the processor (Eiselt [0039] discloses the control by the processor of the gain to attenuate as necessary the strength of the signal seen by the receiver based on the predetermined power range; based on the evidence in the preceding paragraphs and figs. 5A-5C, [0057]-[0060], the processor causes the receiver to increase or decrease the gain seen in fig. 5B to account for decrease or increase of the power (fig. 5A) seen by the receiver in order to maintain the desired constant signal of fig. 5C), wherein the at least one element of the receiver comprises a light detector or an avalanche photodiode (Eiselt [0039] discloses that the photodiode 3 can comprise an avalanche photodiode APD [one element of the receiver comprises both a light detector and an avalanche photodiode – an avalanche photodiode is itself a light detector]).
Eiselt is silent to
(b) sampling, by a processor of the OTDR from a receiver of the OTDR, electrical samples related to a backscatter optical signal;
(c) determining, by the processor, from one or more values of the electrical samples related to the backscatter optical signal;
(d) controlling, by the processor, the receiver to decrease values of the electrical samples related to the backscatter optical signal, without modifying or adjusting optical values of samples of the backscatter optical signal prior to the electrical samples related to the backscatter optical signal being sampled by the at least one element of the receiver;
(e) determining, by the processor, from one or more values of electrical samples related to the backscatter optical signal sampled after step (d) that the at least one element of the receiver would not be operating in the saturated operating state if the values of electrical samples related to the backscatter optical signal sampled by the processor were increased; and
(f) controlling, by the processor, the receiver to increase the values of the electrical samples related to the backscatter optical signal sampled by the processor without modifying or adjusting optical values of the samples of the backscatter optical signal prior to the electrical samples of the backscatter optical signal being sampled by the at least one element of the receiver.
However, Gurusami does address this limitation. Eiselt and Gurusami are considered to be analogous to the present invention because they are optical time domain reflectometry systems.
Gurusami discloses “(b) sampling, by a processor of the OTDR from a receiver of the OTDR, electrical samples related to a backscatter optical signal; (c) determining, by the processor, from one or more values of the electrical samples related to the backscatter optical signal” (Gurusami fig. 1 and [0016] disclose a diagram for an OTDR measurement system; [0034] and fig. 1 disclose a photodetector 32 [analogous to the receiver of the claimed invention], where the output from the photodetector 32 is directed to an analog to digital converter 36; since the analog to digital converter appears downstream from the photodetector, the photodetector is understood to be sampling analog signals [i.e. electrical signals sampled by a receiver of the OTDR]; this reasoning is applicable and reiterated for all mentions of “electrical samples” which follow in the rejection);
“(d) controlling, by the processor, the receiver to decrease values of the electrical samples related to the backscatter optical signal, without modifying or adjusting optical values of samples of the backscatter optical signal prior to the electrical samples related to the backscatter optical signal being sampled by the at least one element of the receiver” (“electrical samples” has been addressed above; Gurusami fig. 1 and [0034] disclose the photodetector 32 [receiver] where the output from the photodetector 32 is immediately directed to a transimpedance amplifier 34, used to amplify the detected signal as desired for further processing – here, the detected signals sampled by Gurusami are not modified or adjusted prior to being sampled by the receiver [i.e. they are sampled by the photodetector and then modified/adjusted by the TIA after detection]; Eiselt has disclosed the other specifics of step (d) in the preceding paragraphs);
“(e) determining, by the processor, from one or more values of electrical samples related to the backscatter optical signal sampled after step (d) that the at least one element of the receiver would not be operating in the saturated operating state if the values of electrical samples related to the backscatter optical signal sampled by the processor were increased” (“electrical samples” has been addressed above); and
(f) controlling, by the processor, the receiver to increase the values of the electrical samples related to the backscatter optical signal sampled by the processor without modifying or adjusting optical values of the samples of the backscatter optical signal prior to the electrical samples of the backscatter optical signal being sampled by the at least one element of the receiver” (“electrical samples” has been addressed above; Gurusami [0034] and fig. 1, as with the preceding limitation, disclose a photodetector 32 [analogous to the receiver of the claimed invention], where the output from the photodetector is directed to the transimpedance amplifier 34, used to amplify the detected signal as desired for further processing – here, the detected signals sampled by Gurusami are not modified or adjusted prior to being sampled by the receiver [i.e. they are sampled by the photodetector and then modified/adjusted by the TIA 34 after detection]; Eiselt has disclosed the other specifics of step (f) in the preceding paragraphs).
22. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt to incorporate (b) sampling, by a processor of the OTDR from a receiver of the OTDR, electrical samples related to a backscatter optical signal; (c) determining, by the processor, from one or more values of the electrical samples related to the backscatter optical signal; (d) controlling, by the processor, the receiver to decrease values of the electrical samples related to the backscatter optical signal, without modifying or adjusting optical values of samples of the backscatter optical signal prior to the electrical samples related to the backscatter optical signal being sampled by the at least one element of the receiver; (e) determining, by the processor, from one or more values of electrical samples related to the backscatter optical signal sampled after step (d) that the at least one element of the receiver would not be operating in the saturated operating state if the values of electrical samples related to the backscatter optical signal sampled by the processor were increased; and (f) controlling, by the processor, the receiver to increase the values of the electrical samples related to the backscatter optical signal sampled by the processor without modifying or adjusting optical values of the samples of the backscatter optical signal prior to the electrical samples of the backscatter optical signal being sampled by the at least one element of the receiver as suggested by Gurusami for the advantage of amplifying a detected signal suitable for further processing (Gurusami [0034]), ensuring no loss of information within the digitization process by parts of the signal being undetectable.
Regarding claim 5, Eiselt when modified by Gurusami discloses the method of claim 1, and Eiselt further teaches the method wherein:
step (d) includes decreasing a gain of the avalanche photodiode (Eiselt figs. 5A-5C and [0039], [0057]-[0060] discloses a trace of gain over time for a backscatter trace, where a decrease in gain is seen to bring the signal seen by the photodiode within an unsaturated state; [0044] also discloses the reduction of gain factor of the avalanche photodiode leading to less saturation of the avalanche photodiode); and
step (f) includes increasing a gain of the avalanche photodiode (Eiselt [0039] disclose the use of the avalanche photodiode wherein the control voltage of the APD is changed automatically depending on the signal strength received by the receiver; since the gain of the avalanche photodiode is decreased within step (d) and the control voltage of the APD is changed automatically depending on the signal strength received, the control voltage/gain of the avalanche photodiode is increased as necessary to conform within the predetermined power range Pmin through Pmax; one of ordinary skill in the art recognizes the proportionality between the control voltage of the APD and gain of the APD wherein an increase of the control voltage of the APD is analogous to an increase of the gain of the APD).
Regarding claim 11, Eiselt when modified by Gurusami discloses the method of claim 1, and further teaches the method wherein the one or more values sampled in step (e) is the same as the one or more values sampled in step (b) (Eiselt fig 5A shows the power backscattered from a FLUT as a response to the probe pulse, [step (b)]; the values sampled in step (e) are the same as those seen in the power backscattered from a FLUT in the sense that the gain mirror of fig. 5B applied to maintain the power seen by the optical signal is dependent on the same values sampled in step (b) – were the values different in this sense, the optical signal to the receiver may not remain between Pmin and P-max).
Regarding claim 12, Eiselt when modified by Gurusami discloses the method of claim 1, and Eiselt further teaches the method wherein the one or more values sampled in step (e) is different than the one or more values sampled in step (b) (Eiselt [0045] discloses that dead zone suppression of a possible embodiment of the method such that a regular operation pulse with constant attenuation/gain is obtained [i.e. step (b)], where large reflections are identified; in subsequent pulses gain/attenuation pulses are supplied in effort to eliminate dead zones – the requirement for subsequent pulses to determine whether the dead zones have been eliminated constitutes the values sampled in step (b) and step (e) as being different).
Regarding claim 13, Eiselt discloses an Optical Time-Domain Reflectometer (OTDR) (Eiselt abstract discloses an optical time-domain reflectometer), comprising:
a laser source operative, under the control of a processor via a pulse generator, for outputting a laser pulse to an optical fiber (Eiselt [0004] and fig. 1 disclose an OTDR comprising a laser which generates an optical pulse [i.e. pulse generator] transmitted into an optical fiber under test (“fiber link under test” or FLUT); [0036] discloses the laser being controlled by a processor 5); and
a receiver for receiving a backscatter optical signal generated by the optical fiber in response to the laser pulse output to the optical fiber (Eiselt [0007] the OTDR measuring a backscattered trace of a FLUT in response to an optical test signal [backscatter signal generated by the optical fiber in response to laser pulse], wherein the backscattered trace is received by a photodiode [a receiver]), wherein the processor is programmed or configured to;
determine from one or more values of samples related to the received backscatter optical signal that at least one element of the receiver is operating in a saturated state (Eiselt [0005] and fig. 2 disclose a typical backscattered trace of a FLUT with dead zones in the trace resulting from the saturation of a photodiode [receiver] receiving the backscattered optical signal; [0011] discloses that an embodiment of the invention comprises a means to adjust and suppress dead zones within the backscattered trace of the FLUT – i.e. a determination is made whether the receiver is in a saturated operating state or not; [0017] discloses that the processor is used to evaluate backscatter traces [including identifying dead zones caused by saturation] – i.e. a determination is made by the processor whether the receiver is in a saturated operating state);
(b) in response to the determining in step (a), control the receiver to decrease one or more values of the samples related to the received backscatter optical signal sampled after step (a), whereupon the at least one element of the receiver is operating in an unsaturated state (Eiselt [0019] discloses that the processor may be used to limit the power of the optical signal [values of the samples of the back scatter sampled] received by the photodiode [receiver] within a predetermined power range [i.e. limiting the strength/intensity of the signals received by the receiver to within a non-saturated state]; the control by the processor can be in response to an identification of large reflections which result in saturation and dead zones as disclosed in fig. 2 and [0005] – therefore the signal sampled is decreased to within an unsaturated operating state for the receiver; [0039] also explores this (see below); [0045] discloses the suppression of dead zones due to saturation, and [0048] discloses the use of a defined gain variation over time with which to account for the reduction of values sampled by the receiver [i.e. reduce the receiver into an unsaturated operating state]);
(c) determine from one or more values of samples related to the received backscatter signal sampled after step (b) that the at least one element of the receiver would not be operating in the saturated operating state if the values of the samples related to the in the backscatter optical signal were increased (Eiselt [0039] discloses the determination of a predetermined power range of signal available to the receiver – a maximum power Pmax is chosen as an upper limit to limit the max power and suppress dead zones, as described in step (d) above; a lower power limit is also chosen Pmin which is set to maintain a minimum signal to noise ratio STNR received by the receiver; for purposes of attenuation, the processor iteratively adjusts the gain of an amplifier (i.e. increasing or decreasing the signal) such that an approximately constant power is seen by the photodiode over time, and the gain can be set/changed in real time based on the strength of the backscatter signals [related to the received backscatter optical signal]; fig. 5A shows raw data seen by the receiver, fig. 5B shows a gain function applied to ensure the signal strength is between Pmin and Pmax, and fig. 5C shows the approx. constant signal seen by the receiver; a determination is made by the processor to adjust the gain function to ensure a constant signal is seen by the receiver – if that determination was not made, no cause for adjustment would exist and a corresponding change in the gain would not exist; the processor adjusts the gain such that the receiver would not be operating in a saturated operating state in order to maintain the signal shown in fig. 5C, whether the values of the samples related to the backscatter optical signals need to be increased or decreased; both gain increases and decreases are seen in fig. 5B to ensure decreased and increased signal P(t) of fig. 5A respectively); and
(d) in response to step (c), control the receiver to increase one or more values of the samples related to the backscatter optical signal sampled after step (c) (Eiselt [0039] discloses the control by the processor of the gain to attenuate as necessary the strength of the signal seen by the receiver based on the predetermined power range; based on the evidence in the preceding paragraphs and figs. 5A-5C, [0057]-[0060], the processor causes the receiver to increase or decrease the gain seen in fig. 5B to account for decrease or increase of the power (fig. 5A) seen by the receiver in order to maintain the desired constant signal of fig. 5C), wherein the at least one element of the receiver comprises a light detector or an avalanche photodiode (Eiselt [0039] discloses that the photodiode 3 can comprise an avalanche photodiode APD [one element of the receiver comprises both a light detector and an avalanche photodiode – an avalanche photodiode is itself a light detector]).
Eiselt is silent to wherein the processor is programmed or configured to:
(a) determine from one or more values of electrical samples related to the received backscatter optical signal;
(b) control the receiver to decrease one or more values of the electrical samples related to the received optical signal sampled after step (a) without modifying or adjusting optical values of the samples of the received backscatter optical signal prior to the electrical samples of the received backscatter optical signal being sampled by the at least one element of the receiver;
(c) determine from one or more values of electrical samples related to the received backscatter optical signal sampled after step (b) that the at least one element of the receiver would not be operating in the saturated operating state if the values of the electrical samples related to the received backscatter optical signal were increased; and
(d) control the receiver to increase one or more values of the electrical samples related to the received backscatter optical signal sampled after step (c) without modifying or adjusting optical values of the samples of the received backscatter optical signal prior to the electrical samples of the received backscatter optical signal being sampled by the at least one element of the receiver.
However, Gurusami does address this limitation. Eiselt and Gurusami are considered to be analogous to the present invention because they are optical time domain reflectometry systems.
Gurusami discloses “wherein the processor is programmed or configured to:
(a) determine from one or more values of electrical samples related to the received backscatter optical signal; (b) control the receiver to decrease one or more values of the electrical samples related to the received optical signal sampled after step (a)” (Gurusami fig. 1 and [0016] disclose a diagram for an OTDR measurement system; [0034] and fig. 1 disclose a photodetector 32 [analogous to the receiver of the claimed invention], where the output from the photodetector 32 is directed to an analog to digital converter 36; since the analog to digital converter appears downstream from the photodetector, the photodetector is understood to be sampling analog signals [i.e. electrical signals sampled by a receiver of the OTDR]; this reasoning is applicable and reiterated for all mentions of “electrical samples” which follow in the rejection) “without modifying or adjusting optical values of the samples of the received backscatter optical signal prior to the electrical samples of the received backscatter optical signal being sampled by the at least one element of the receiver” (see rejection under 35 U.S.C. 112(b) above; Gurusami [0034] and fig. 1, as with the preceding limitation, disclose a photodetector 32 [analogous to the receiver of the claimed invention], where the output from the photodetector is directed to a transimpedance amplifier 34, used to amplify the detected signal as desired for further processing – here, the detected signals sampled by Gurusami are not modified or adjusted prior to being sampled by the receiver [i.e. they are sampled by the photodetector and then modified/adjusted by the TIA 34 after detection]; Eiselt has disclosed the other specifics of this step the preceding paragraphs),
“(c) determine from one or more values of electrical samples related to the received backscatter optical signal sampled after step (b) that the at least one element of the receiver would not be operating in the saturated operating state if the values of the electrical samples related to the received backscatter optical signal were increased” (“electrical samples” has been addressed above); and
“(d) control the receiver to increase one or more values of the electrical samples related to the received backscatter optical signal sampled after step (c) without modifying or adjusting optical values of the samples of the received backscatter optical signal prior to the electrical samples of the received backscatter optical signal being sampled by the at least one element of the receiver” (“electrical samples” has been addressed above; Gurusami [0034] and fig. 1, as with the preceding limitation, disclose a photodetector 32 [analogous to the receiver of the claimed invention], where the output from the photodetector is directed to the transimpedance amplifier 34, used to amplify the detected signal as desired for further processing – here, the detected signals sampled by Gurusami are not modified or adjusted prior to being sampled by the receiver [i.e. they are sampled by the photodetector and then modified/adjusted by the TIA 34 after detection]; Eiselt has disclosed the other specifics of this step the preceding paragraphs).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt to incorporate wherein the processor is programmed or configured to: (a) determine from one or more values of electrical samples related to the received backscatter optical signal; (b) control the receiver to decrease one or more values of the electrical samples related to the received optical signal sampled after step (a) without modifying or adjusting optical values of the samples of the received backscatter optical signal prior to the electrical samples of the received backscatter optical signal being sampled by the at least one element of the receiver; (c) determine from one or more values of electrical samples related to the received backscatter optical signal sampled after step (b) that the at least one element of the receiver would not be operating in the saturated operating state if the values of the electrical samples related to the received backscatter optical signal were increased; and (d) control the receiver to increase one or more values of the electrical samples related to the received backscatter optical signal sampled after step (c) without modifying or adjusting optical values of the samples of the received backscatter optical signal prior to the electrical samples of the received backscatter optical signal being sampled by the at least one element of the receiver as suggested by Gurusami for the advantage of amplifying a detected signal suitable for further processing (Gurusami [0034]), ensuring no loss of information within the digitization process by parts of the signal being undetectable.
Regarding claim 15, Eiselt when modified by Gurusami discloses the OTDR of claim 13, and Eiselt further teaches the OTDR wherein:
step (b) includes decreasing a gain of the avalanche photodiode (Eiselt figs. 5A-5C and [0039], [0057]-[0060] discloses a trace of gain over time for a backscatter trace, where a decrease in gain is seen to bring the signal seen by the photodiode within an unsaturated state; [0044] also discloses the reduction of gain factor of the avalanche photodiode leading to less saturation of the avalanche photodiode); and
step (d) includes increasing a gain of the avalanche photodiode (Eiselt [0039] disclose the use of the avalanche photodiode wherein the control voltage of the APD is changed automatically depending on the signal strength received by the receiver; since the gain of the avalanche photodiode is decreased within step (d) and the control voltage of the APD is changed automatically depending on the signal strength received, the control voltage/gain of the avalanche photodiode is increased as necessary to conform within the predetermined power range Pmin through Pmax; one of ordinary skill in the art recognizes the proportionality between the control voltage of the APD and gain of the APD wherein an increase of the control voltage of the APD is analogous to an increase of the gain of the APD).
Regarding claim 17, Eiselt discloses an Optical Time-Domain Reflectometer (OTDR) (Eiselt abstract discloses an optical time-domain reflectometer), comprising:
means for outputting a laser pulse to an optical fiber (Eiselt [0007] and [0036] discloses a laser 2 [means for outputting] which is adapted to generate an optical test signal via an optical pulse into a “fiber link under test” or FLUT [pulse to an optical fiber]);
means for receiving an optical backscatter signal generated by the optical fiber in response to the laser pulse output to the optical fiber (Eiselt [0007] and [0036] discloses the OTDR measuring a backscattered trace of a FLUT in response to an optical test signal [backscatter signal generated by the optical fiber in response to laser pulse], wherein the backscattered trace is detected/measured/received by a photodiode [means for receiving]; examiner notes that [0039] discloses other components including variable optical attenuator (VOA) or semiconductor optical amplifier (SOA) which both also receive the backscatter signal generated by the optical fiber, and therefore the means for receiving is not limited to a photodiode);
means for determining from values of samples related to the received optical backscatter signal that at least one element of the means for receiving is operating in a saturated state (Eiselt [0005] and fig. 2 disclose a typical backscattered trace of a FLUT with dead zones in the trace resulting from the saturation of a photodiode [means for receiving samples related to received optical backscatter signal; [0011] discloses that an embodiment of the invention comprises a means to adjust and suppress dead zones within the backscattered trace of the FLUT – i.e. a determination is made whether the receiver is in a saturated operating state or not; [0017] discloses that a processor [means for determining] is used to evaluate backscatter traces [including identifying dead zones caused by saturation] – i.e. a determination is made by the processor [means for receiving] whether the photodiode is in a saturated operating state; and
a means for controlling the means for receiving to decrease the values of the samples related to the optical backscatter signal received by the means for determining such that the at least one element of the means for receiving is operating in an unsaturated state (Eiselt [0019] discloses that the processor is used to limit the power of the optical signal [values of the samples of the back scatter sampled] received by the photodiode [means for receiving] within a predetermined power range (i.e. limiting the strength/intensity of the signals received by the receiver to within a non-saturated state) [means for controlling the means for receiving]; the control by the processor can be in response to an identification of large reflections which result in saturation and dead zones as disclosed in fig. 2 and [0005] – therefore the signal sampled is decreased to within an unsaturated operating state for the means for receiving; [0039] also explores this (see below); [0045] discloses the suppression of dead zones due to saturation, and [0048] discloses the use of a defined gain variation over time with which to account for the reduction of values sampled by the photodiode [i.e. reduce at least one element of the means for receiving into an unsaturated operating state]), wherein:
the means for determining determines from the values of the samples related to the optical backscatter signal acquired by the means for receiving after decreasing the values of the samples related to the optical backscatter signal that the at least one element of the means for receiving would not be operating in a saturated state if the values of the samples related to the optical backscatter signal were increased (Eiselt [0039] discloses the determination of a predetermined power range of signal available to the photodiode – a maximum power Pmax is chosen as an upper limit to limit the max power and suppress dead zones, as described above; a lower power limit is also chosen Pmin which is set to maintain a minimum signal to noise ratio STNR received by the means for receiving; for purposes of attenuation, the processor [means for determining/controlling] iteratively adjusts the gain of an amplifier (i.e. increasing or decreasing the signal) such that an approximately constant power is seen by the photodiode over time, and the gain can be set/changed in real time based on the strength of the backscatter signals; fig. 5A shows raw data seen by the receiver, fig. 5B shows a gain function applied to ensure the signal strength is between Pmin and Pmax, and fig. 5C shows the approx. constant signal seen by the receiver; a determination is made by the processor to adjust the gain function to ensure a constant signal is seen by the receiver – if that determination was not made, no cause for adjustment would exist and a corresponding change in the gain would not exist; the processor adjusts the gain such that the receiver would not be operating in a saturated operating state in order to maintain the signal shown in fig. 5C, whether the values of the samples related to the optical backscatter signals need to be increased or decreased; both gain increases and decreases are seen in fig. 5B to ensure decreased and increased signal P(t) of fig. 5A respectively); and
the means for controlling controls the means for receiving to increase the values of the samples related to the optical backscatter signal acquired by the means for receiving after the means for determining determines that the at least one element of the means for receiving would not be operating in the saturated state if the values related to samples of the optical backscatter signal were increased (Eiselt [0039] discloses the control by the processor of the gain (means for controlling controls the means for receiving) to attenuate as necessary the strength of the signal seen by the means for receiving based on the predetermined power range; based on the evidence in the preceding paragraphs and figs. 5A-5C, [0057]-[0060], the processor causes the photodiode to increase or decrease the gain seen in fig. 5B to account for decrease or increase of the power (fig. 5A) seen by the receiver in order to maintain the desired constant signal of fig. 5C), and wherein the at least one element of the means for receiving comprises a light detector or an avalanche photodiode (Eiselt [0039] discloses that the photodiode 3 can comprise an avalanche photodiode APD [one element of the receiver comprises both a light detector and an avalanche photodiode – an avalanche photodiode is itself a light detector]).
Eiselt is silent to means for determining from values of electrical samples related to the received optical backscatter signal;
means for controlling the means for receiving to decrease the values of the electrical samples related to the received optical backscatter signal received by the means for determining such that the at least one element of the means for receiving is operating in an unsaturated state without modifying or adjusting optical values of the samples of the optical backscatter optical signal prior to the electrical samples related to the optical backscatter signal being sampled by the at least one element of the means for receiving, wherein:
the means for receiving determines from the values of the electrical samples related to the optical backscatter signal acquired by the means for receiving after decreasing the values of the electrical samples related to the optical backscatter signal that the at least one element of the means for receiving would not be operating in a saturated state if the values of the electrical samples related to the optical backscatter signal were increased; and
the means for controlling controls the means for receiving to increase the values of the electrical samples related to the optical backscatter signal acquired by the means for receiving after the means for determining determines that the at least one element of the means for receiving would not be operating in the saturated state if the electrical values related to samples of the optical backscatter signal were increased without modifying or adjusting the optical values of the samples of the optical backscatter signal prior to the electrical samples of the received optical backscatter signal being sampled by the at least one element of the receiver.
However, Gurusami does address this limitation. Eiselt and Gurusami are considered to be analogous to the present invention because they are optical time domain reflectometry systems.
Gurusami discloses a “means for determining from values of electrical samples related to the received optical backscatter signal” (Gurusami fig. 1 and [0016] disclose a diagram for an OTDR measurement system; [0034] and fig. 1 disclose a photodetector 32 [analogous to the receiver of the claimed invention], where the output from the photodetector 32 is directed to an analog to digital converter 36; since the analog to digital converter appears downstream from the photodetector, the photodetector is understood to be sampling analog signals [i.e. electrical signals sampled by a receiver of the OTDR]; this reasoning is applicable and reiterated for all mentions of “electrical samples” which follow in the rejection)
“means for controlling the means for receiving to decrease the values of the electrical samples related to the received optical backscatter signal received by the means for determining such that the at least one element of the means for receiving is operating in an unsaturated state” (“electrical samples” has been addressed above) “without modifying or adjusting optical values of the samples of the optical backscatter optical signal prior to the electrical samples related to the optical backscatter signal being sampled by the at least one element of the means for receiving” (see rejection under 35 U.S.C. 112(b) above; “electrical samples” has been addressed above; Gurusami [0034] and fig. 1, as with the preceding limitation, disclose a photodetector 32 [analogous to the means of receiving of the claimed invention], where the output from the photodetector is directed to the transimpedance amplifier 34, used to amplify the detected signal as desired for further processing – here, the detected signals sampled by Gurusami are not modified or adjusted prior to being sampled by the receiver [i.e. they are sampled by the photodetector and then modified/adjusted by the TIA 34 after detection]; Eiselt has disclosed the other specifics of the “means for controlling the means for receiving” limitation in the preceding paragraphs), wherein
“the means for receiving determines from the values of the electrical samples related to the optical backscatter signal acquired by the means for receiving after decreasing the values of the electrical samples related to the optical backscatter signal that the at least one element of the means for receiving would not be operating in a saturated state if the values of the electrical samples related to the optical backscatter signal were increased” (“electrical samples has been addressed above); and
“the means for controlling controls the means for receiving to increase the values of the electrical samples related to the optical backscatter signal acquired by the means for receiving after the means for determining determines that the at least one element of the means for receiving would not be operating in the saturated state if the electrical values related to samples of the optical backscatter signal were increased” (see rejection under 35 U.S.C. 112(b) above; “electrical samples” has been disclosed above, and analogous reasoning applies with regards to “electrical values”) “without modifying or adjusting the optical values of the samples of the optical backscatter signal prior to the electrical samples of the received optical backscatter signal being sampled by the at least one element of the receiver” (see rejection under 35 U.S.C. 112(b) above; Gurusami [0034] and fig. 1, as with the preceding limitation, disclose a photodetector 32 [analogous to the receiver of the claimed invention], where the output from the photodetector is directed to the transimpedance amplifier 34, used to amplify the detected signal as desired for further processing – here, the detected signals sampled by Gurusami are not modified or adjusted prior to being sampled by the receiver [i.e. they are sampled by the photodetector and then modified/adjusted by the TIA 34 after detection]; Eiselt has disclosed the other specifics of the limitation not explicitly addressed by Gurusami).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt to incorporate a means for determining from values of electrical samples related to the received optical backscatter signal; means for controlling the means for receiving to decrease the values of the electrical samples related to the received optical backscatter signal received by the means for determining such that the at least one element of the means for receiving is operating in an unsaturated state without modifying or adjusting optical values of the samples of the optical backscatter optical signal prior to the electrical samples related to the optical backscatter signal being sampled by the at least one element of the means for receiving, wherein: the means for receiving determines from the values of the electrical samples related to the optical backscatter signal acquired by the means for receiving after decreasing the values of the electrical samples related to the optical backscatter signal that the at least one element of the means for receiving would not be operating in a saturated state if the values of the electrical samples related to the optical backscatter signal were increased; and the means for controlling controls the means for receiving to increase the values of the electrical samples related to the optical backscatter signal acquired by the means for receiving after the means for determining determines that the at least one element of the means for receiving would not be operating in the saturated state if the electrical values related to samples of the optical backscatter signal were increased without modifying or adjusting the optical values of the samples of the optical backscatter signal prior to the electrical samples of the received optical backscatter signal being sampled by the at least one element of the receiver as suggested by Gurusami for the advantage of amplifying a detected signal suitable for further processing (Gurusami [0034]), ensuring no loss of information within the digitization process by parts of the signal being undetectable.
Regarding claim 18, Eiselt when modified by Gurusami discloses the OTDR of claim 17, and Eiselt further teaches the OTDR, comprising at least one of the following:
the means for outputting the laser pulse to the optical fiber comprises a laser source (Eiselt [0007] and [0036] discloses that the means for outputting the laser pulse to the optical fiber is a laser [i.e. a laser source]);
the means for receiving comprises the light detector and a transimpedance amplifier (TIA), or the avalanche photodiode (Eiselt [0039] discloses an avalanche photodiode as part of the means for receiving, considered by one of ordinary skill in the art as being a form of light detector (as indicated in independent claim 17); the transimpedance amplifier here is not considered due to the “or” statement);
the means for determining comprises a processor (Eiselt [0036] discloses that the processor 5 aids in controlling the optical system based on signals received (i.e. determined) by the means for receiving [the processor is a means for determining]); and
the means for controlling comprises the processor (Eiselt [0036] discloses the processor 5 controls aspects of the optical system [the processor is a means for controlling]).
Claims 2 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Eiselt in view of Gurusami, in view of US 2022/0345216 A1 by Charlène Roux et al. (herein after “Roux”).
Regarding claim 2, Eiselt when modified by Gurusami discloses the method of claim 1, and Eiselt further teaches the method wherein:
elements of the receiver include the light detector and an amplifier (Eiselt [0039] discloses the use of a photodiode 3 and avalanche photodiode as light detectors, as disclosed in claim 1 above, and discloses the use of a semiconductor optical amplifier [an amplifier]));
step (d) includes the amplifier having a lower gain (Eiselt [0039] discloses the gain of the semiconductor optical amplifier being adjusted iteratively by the processor to maintain the power of an optical signal received by the light detector within the predetermined range; figs. 5A-5C show a decreased gain for a peak in backscatter signal P(t) [the peak meaning operation within a saturated state and thus decreasing the gain to counteract said peak]); and
step (f) includes the amplifier having an higher gain (Eiselt [0039], [0043], [0057]-[0060] and figs. 5A-5C disclose that for a situation where it is determined an increase in backscatter signal would result in an unsaturated state, a higher gain is utilized to amplify signals outside of dead zones).
Eiselt when modified by Gurusami is silent to the method of claim 1, wherein elements of the receiver include a transimpedance amplifier (TIA); step (d) includes selecting a transresistance unit of the TIA having a lower gain; and step (f) includes selecting a transresistance unit of the TIA having a higher gain.
However, Roux does address this limitation. Eiselt and Roux are considered to be analogous to the present invention because they are related to optical time-domain reflectometer devices for optical fiber inspection.
Roux discloses the method of claim 1, “wherein elements of the receiver include a transimpedance amplifier (TIA)” (Roux [0042] discloses the use of a transimpedance amplifier (TIA) i.e. the TIA 630 of fig. 6 which receives data transmitted from an optical fiber under inspection within an optical attenuator 600 [i.e. within a device used partially to attenuate signals as needed based on signal power obtained by receiving component]);
“step (d) includes selecting a transresistance unit of the TIA having a lower gain; and
step (f) includes selecting a transresistance unit of the TIA having a higher gain” (Roux [0058] discloses that the transimpedance amplifier is used to determine the presence of saturation by determining whether the signal crosses a predefined saturation level threshold, or else the data is not decodable; as above, the TIA 630 is utilized within an optical attenuator device [i.e. used within a device to adjust signal strength as necessary], and the optical attenuator (and therefore the TIA) is used to manage the level of optical power seen by the receiver to ensure saturation is not present; while Roux does not explicitly describe selecting a transresistance unit of the TIA having higher or lower gain, Roux does disclose the TIA’s role within an optical attenuator related to determining whether saturation is occurring or not to avoid saturation – based on Eiselt and its ability to adjust the gain related to optical receiving components and based on the role of the TIA in Roux within an optical attenuator, one of ordinary skill in the art would recognize consider the TIA as required in mitigating saturation [and therefore enabling higher or lower gain as necessary as described within the steps of claim 1]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami to incorporate wherein elements of the receiver include a transimpedance amplifier (TIA); step (d) includes selecting a transresistance unit of the TIA having a lower gain; and step (f) includes selecting a transresistance unit of the TIA having a higher gain as suggested by Roux for the advantage of ensuring a predefined saturation level is not reached, therefore enabling data to be decoded, and enabling the successful linear conversion from optical power to output current via the receiving device (Roux [0058]).
Regarding claim 14, Eiselt when modified by Gurusami discloses the OTDR of claim 13, and further teaches the OTDR wherein elements of the receiver include the light detector and an amplifier (Eiselt [0039] discloses the use of a photodiode 3 and avalanche photodiode as light detectors, as disclosed in claim 13 above, and discloses the use of a semiconductor optical amplifier [an amplifier]));
step (b) includes the amplifier having a lower gain (Eiselt [0039] discloses the gain of the semiconductor optical amplifier being adjusted iteratively by the processor to maintain the power of an optical signal received by the light detector within the predetermined range; figs. 5A-5C show a decreased gain for a peak in backscatter signal P(t) [the peak meaning operation within a saturated state and thus decreasing the gain to counteract said peak]); and
step (d) includes the amplifier having a higher gain (Eiselt [0039], [0043], [0057]-[0060] and figs. 5A-5C disclose that for a situation where it is determined an increase in backscatter signal would result in an unsaturated state, a higher gain is utilized to amplify signals outside of dead zones).
Eiselt when modified by Gurusami is silent to the OTDR of claim 13, wherein elements of the receiver include a transimpedance amplifier (TIA); step (b) includes selecting a transresistance unit of the TIA having a lower gain; and step (d) includes selecting a transresistance unit of the TIA having a higher gain.
However, Roux does address this limitation. Eiselt, Gurusami, and Roux are considered to be analogous to the present invention because they are related to optical time-domain reflectometer devices for optical fiber inspection.
Roux discloses the OTDR of claim 13, “wherein elements of the receiver include a transimpedance amplifier (TIA)” (Roux [0042] discloses the use of a transimpedance amplifier (TIA) i.e. the TIA 630 of fig. 6 which receives data transmitted from an optical fiber under inspection within an optical attenuator 600 [i.e. within a device used partially to attenuate signals as needed based on signal power obtained by receiving component]);
“step (d) includes selecting a transresistance unit of the TIA having a lower gain; and
step (f) includes selecting a transresistance unit of the TIA having a higher gain” (Roux [0058] discloses that the transimpedance amplifier is used to determine the presence of saturation by determining whether the signal crosses a predefined saturation level threshold, or else the data is not decodable; as above, the TIA 630 is utilized within an optical attenuator device [i.e. used within a device to adjust signal strength as necessary], and the optical attenuator (and therefore the TIA) is used to manage the level of optical power seen by the receiver to ensure saturation is not present; while Roux does not explicitly describe selecting a transresistance unit of the TIA having higher or lower gain, Roux does disclose the TIA’s role within an optical attenuator related to determining whether saturation is occurring or not to avoid saturation – based on Eiselt and its ability to adjust the gain related to optical receiving components and based on the role of the TIA in Roux within an optical attenuator, one of ordinary skill in the art would recognize consider the TIA as required in mitigating saturation [and therefore enabling higher or lower gain as necessary as described within the steps of claim 13]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami to incorporate wherein elements of the receiver include a transimpedance amplifier (TIA); step (d) includes selecting a transresistance unit of the TIA having a lower gain; and step (f) includes selecting a transresistance unit of the TIA having a higher gain as suggested by Roux for the advantage of ensuring a predefined saturation level is not reached, therefore enabling data to be decoded, and enabling the successful linear conversion from optical power to output current via the receiving device (Roux [0058]).
Claims 3-4 are rejected under 35 U.S.C. 103 as being unpatentable over Eiselt in view of Gurusami, in view of Roux, and further in view of US 2010/0271622 A1 by Shigeo Hori (herein after “Hori”).
Regarding claim 3, Eiselt when modified by Gurusami and Roux discloses the method of claim 2. Eiselt when modified by Gurusami and Roux is silent to the method of claim 2, wherein the higher gain of the TIA in step (f) is the same as a gain of the TIA prior to step (d).
However, Hori does address this limitation. Eiselt, Gurusami, Roux, and Hori are considered to be analogous to the present invention because they are related to optical time-domain reflectometer devices for optical fiber inspection.
Hori discloses the method of claim 2, “wherein the higher gain of the TIA in step (f) is the same as a gain of the TIA prior to step (d)” (Hori figs. 1 and 6-7, and [0220]-[0230] describes a process by which an attenuator (ATT) comprised of an amplification section 57 [analogous to the transimpedance amplifier TIA of Eiselt in view of Gurusami and Roux] saturates an incoming waveform from an OTDR measurement; fig. 6 shows signal strength for an OTDR measurement as a function of distance (this is an analogous signal strength plots described in Eiselt); fig. 7 discloses gains, effective measurement level ranges, etc. for each marker marked in fig. 6; [0220]-[0230] describes the means for setting appropriate attenuation conditions (ATT section 11 fig. 1), where fig. 6 provides example amplifying gains set per marker; [0235] describes that an OTDR measurement is taken and results displayed iteratively for each marker 1 through 6, but that after each marker measurement/display, the ATT value setting condition process occurs again adjusting the gain – markers 3 and 5 for example, both have a same amplifying gain, such that the increased gain of the optical component (the TIA of Roux, or the attenuator of Hori, or some other attenuating light receiver) in step (f) [where a determination is made to increase values of the samples of the backscatter signal] is the same as a previous gain prior to step (d)).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami and Roux to incorporate wherein the higher gain of the TIA in step (f) is the same as a gain of the TIA prior to step (d) as suggested by Hori for the advantage of ensuring the measurement of a OTDR waveform can be measured of over a wide range with a good signal to noise ratio not less than a predetermined value, thereby increasing the ease of measurement taking and fidelity of the measurements themselves (Hori [0079]).
Regarding claim 4, Eiselt when modified by Gurusami and Roux discloses the method of claim 2. Eiselt when modified by Gurusami and Roux is silent to the method of claim 2, wherein the higher gain of the TIA in step (f) is different than a gain of the TIA prior to step (d).
However, Hori does address this limitation.
Hori discloses the method of claim 2, “wherein the higher gain of the TIA in step (f) is different than a gain of the TIA prior to step (d)” (Hori figs. 1 and 6-7, and [0220]-[0230] describes a process by which an attenuator (ATT) comprised of an amplification section 57 [analogous to the transimpedance amplifier TIA of Eiselt in view of Gurusami and Roux] saturates an incoming waveform from an OTDR measurement; fig. 6 shows signal strength for an OTDR measurement as a function of distance (this is an analogous signal strength plots described in Eiselt); fig. 7 discloses gains, effective measurement level ranges, etc. for each marker marked in fig. 6; [0220]-[0230] describes the means for setting appropriate attenuation conditions (ATT section 11 fig. 1), where fig. 6 provides example amplifying gains set per marker; [0235] describes that an OTDR measurement is taken and results displayed iteratively for each marker 1 through 6, but that after each marker measurement/display, the ATT value setting condition process occurs again adjusting the gain – markers 2 and 3 for example, both have a differing amplifying gain, such that the increased gain of the optical component (the TIA of Roux, or the attenuator of Hori, or some other attenuating light receiver) in step (f) [where a determination is made to increase values of the samples of the backscatter signal] is different than a previous gain prior to step (d)).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami and Roux to incorporate wherein the higher gain of the TIA in step (f) is different than a gain of the TIA prior to step (d) as suggested by Hori for the advantage of ensuring the measurement of a OTDR waveform can be measured of over a wide range with a good signal to noise ratio not less than a predetermined value, thereby increasing the ease of measurement taking and fidelity of the measurements themselves (Hori [0079]).
Claims 6-7 are rejected under 35 U.S.C. 103 as being unpatentable over Eiselt in view of Gurusami, and further in view Hori.
Regarding claim 6, Eiselt when modified by Gurusami discloses the method of claim 5. Eiselt when modified by Gurusami is silent to the method of claim 5, wherein the increased gain of the avalanche photodiode in step (f) is the same as a gain of the avalanche photodiode prior to step (d).
However, Hori does address this limitation. Eiselt, Gurusami, and Hori are considered to be analogous to the present invention because they are optical time domain reflectometry systems.
Hori discloses the method of claim 5, “wherein the increased gain of the avalanche photodiode in step (f) is the same as a gain of the avalanche photodiode prior to step (d)” (Hori figs. 6-7, and [0220]-[0230] describes a process by which an attenuator (ATT) saturates an incoming waveform from an OTDR measurement; fig. 6 shows signal strength for an OTDR measurement as a function of distance (this is an analogous signal strength plots described in Eiselt); fig. 7 discloses gains, effective measurement level ranges, etc. for each marker marked in fig. 6; [0220]-[0230] describes the means for setting appropriate attenuation conditions (ATT section 11 fig. 1), where fig. 6 provides example amplifying gains set per marker; [0235] describes that an OTDR measurement is taken and results displayed iteratively for each marker 1 through 6, but that after each marker measurement/display, the ATT value setting condition process occurs again adjusting the gain – markers 3 and 5 for example, both have a same amplifying gain, such that the increased gain of the optical component (the avalanche photodiode of Eiselt, or the attenuator of Hori) in step (f) [where a determination is made to increase values of the samples of the backscatter signal] is the same as a previous gain prior to step (d)).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami to incorporate wherein the increased gain of the avalanche photodiode in step (f) is the same as a gain of the avalanche photodiode prior to step (d) as suggested by Hori for the advantage of ensuring the measurement of a OTDR waveform can be measured of over a wide range with a good signal to noise ratio not less than a predetermined value, thereby increasing the ease of measurement taking and fidelity of the measurements themselves (Hori [0079]).
Regarding claim 7, Eiselt when modified by Gurusami discloses the method of claim 5. Eiselt when modified by Gurusami is silent to the method of claim 5, wherein the increased gain of the avalanche photodiode in step (f) is different than a gain of the avalanche photodiode prior to step (d).
However, Hori does address this limitation.
Hori discloses the method of claim 5, “wherein the increased gain of the avalanche photodiode in step (f) is different than a gain of the avalanche photodiode prior to step (d)” (Hori, as with claim 6 above, figs. 6-7, and [0220]-[0230] describes a process by which an attenuator (ATT) saturates an incoming waveform from an OTDR measurement; fig. 6 shows signal strength for an OTDR measurement as a function of distance (this is an analogous signal strength plots described in Eiselt); fig. 7 discloses gains, effective measurement level ranges, etc. for each marker marked in fig. 6; [0220]-[0230] describes the means for setting appropriate attenuation conditions (ATT section 11 fig. 1), where fig. 6 provides example amplifying gains set per marker; [0235] describes that an OTDR measurement is taken and results displayed iteratively for each marker 1 through 6, but that after each marker measurement/display, the ATT value setting condition process occurs again adjusting the gain – markers 2 and 3 for example, have a differing amplifying gain, such that the increased gain of the optical component (the avalanche photodiode of Eiselt, or the attenuator of Hori) in step (f) [where a determination is made to increase values of the samples of the backscatter signal] is different than a previous gain prior to step (d)).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami to incorporate wherein the increased gain of the avalanche photodiode in step (f) is different than a gain of the avalanche photodiode prior to step (d) as suggested by Hori for the advantage of ensuring the measurement of a OTDR waveform can be measured of over a wide range with a good signal to noise ratio not less than a predetermined value, thereby increasing the ease of measurement taking and fidelity of the measurements themselves (Hori [0079]).
Claims 19-22 are rejected under 35 U.S.C. 103 as being unpatentable over Eiselt in view of Gurusami, and further in view of US 2022/0128434 A1 by Stephane Perron et al. (“Perron”).
Regarding claim 19, Eiselt when modified by Gurusami discloses the OTDR of claim 18. Eiselt when modified by Gurusami is silent to the OTDR of claim 18, wherein the means for receiving comprises one of the following:
the light detector converting the received optical backscatter signal into a first electrical signal that the TIA converts to a second electrical signal, having an amplitude that is under the control of the processor, that an analog-to-digital converter (ADC) converts into the samples of the received optical backscatter signal, wherein the samples of the received optical backscatter signal are digitized samples; or
the avalanche photodiode converting the received the optical backscatter signal into an electrical signal that an ADC converts into the samples of the received optical backscatter signal, wherein the samples of the received optical backscatter signal are digitized samples.
However, Perron does address this limitation. Eiselt, Gurusami, and Perron are considered to be analogous to the present invention because they are related to optical time-domain reflectometer devices for optical fiber inspection.
Perron discloses the OTDR of claim 18, “wherein the means for receiving comprises one of the following:
the light detector converting the received optical backscatter signal into a first electrical signal that the TIA converts to a second electrical signal, having an amplitude that is under the control of the processor, that an analog-to-digital converter (ADC) converts into the samples of the received optical backscatter signal, wherein the samples of the received optical backscatter signal are digitized samples; or
the avalanche photodiode converting the received the optical backscatter signal into an electrical signal that an ADC converts into the samples of the received optical backscatter signal, wherein the samples of the received optical backscatter signal are digitized samples” (based on the ‘or’ statement of the claim, only the second option is considered here; Perron [0241] and fig. 17 disclose a detection assembly 1056 which comprise a light detector 1066 [such as an avalanche photodiode as with Eiselt] that is in electrical communication with an analog to digital converter 1068, where the detected return light signal is converted from an electrical signal into a digital signal for data storage and processing and [0240] the returned light signal is a received backscatter signal from an optical fiber under test [the photodiode receives an optical backscatter signal and converts the received signal into digital samples).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami to incorporate wherein the means for receiving comprises the avalanche photodiode converting the received the optical backscatter signal into an electrical signal that an ADC converts into the samples of the received optical backscatter signal, wherein the samples of the received optical backscatter signal are digitized samples as suggested by Perron for the advantage of providing an explicit means for storing and later processing backscatter data received by the avalanche photodiode (Perron [0241]).
Regarding claim 20, Eiselt when modified by Gurusami discloses the method of claim 1. Eiselt when modified by Gurusami is silent to the method of claim 1, wherein the electrical samples in steps (b) and (e) are digital signals output to the processor by an analog-to-digital converter of the receiver of the OTDR.
However, Perron does address this limitation. Eiselt, Gurusami, and Perron are considered to be analogous to the present invention because they are related to optical time-domain reflectometer devices for optical fiber inspection.
Perron discloses the method of claim 1, “wherein the electrical samples in steps (b) and (e) are digital signals output to the processor by an analog-to-digital converter of the receiver of the OTDR” (Perron [0241] and fig. 17 disclose a detection assembly 1056 which comprise a light detector 1066 [such as a photodiode as with Eiselt] that is in electrical communication with an analog to digital converter 1068, where the detected return light signal is converted from an electrical signal into a digital signal for data storage and processing and [0240] the returned light signal is a received backscatter signal from an optical fiber under test; the samples acquired in steps (b) and (e) obtained by the photodiode would be digital samples already converted by the analog to digital converter of Perron received by the processor (i.e. received by the controller 1070 of Perron); the presence of electrical signals within the system has been disclosed by Gurusami within claim 17 above).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami to incorporate wherein the electrical samples in steps (b) and (e) are digital signals output to the processor by an analog-to-digital converter of the receiver of the OTDR as suggested by Perron for the advantage of providing an explicit means for storing and later processing backscatter data received by the avalanche photodiode (Perron [0241]).
Regarding claim 21, Eiselt when modified by Gurusami discloses the OTDR of claim 13. Eiselt when modified by Gurusami is silent to the OTDR of claim 13, wherein the electrical samples in steps (a) and (c) are digital signals output to the processor by an analog-to-digital converter of the receiver of the OTDR.
However, Perron does address this limitation. Eiselt, Gurusami, and Perron are considered to be analogous to the present invention because they are related to optical time-domain reflectometer devices for optical fiber inspection.
Perron discloses the OTDR of claim 13, “wherein the electrical samples in steps (a) and (c) are digital signals output to the processor by an analog-to-digital converter of the receiver of the OTDR” (Perron [0241] and fig. 17 disclose a detection assembly 1056 which comprise a light detector 1066 [such as a photodiode as with Eiselt] that is in electrical communication with an analog to digital converter 1068, where the detected return light signal is converted from an electrical signal into a digital signal for data storage and processing and [0240] the returned light signal is a received backscatter signal from an optical fiber under test; the samples acquired in steps (a) and (c) obtained by the photodiode would be digital samples already converted by the analog to digital converter of Perron received by the processor (i.e. received by the controller 1070 of Perron); the presence of electrical signals within the system has been disclosed by Gurusami within claim 17 above).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami to incorporate wherein the electrical samples in steps (a) and (c) are digital signals output to the processor by an analog-to-digital converter of the receiver of the OTDR as suggested by Perron for the advantage of providing an explicit means for storing and later processing backscatter data received by the avalanche photodiode (Perron [0241]).
Regarding claim 22, Eiselt when modified by Gurusami discloses the OTDR of claim 17. Eiselt when modified by Gurusami is silent to the OTDR of claim 17, wherein the means for receiving further comprises an analog-to-digital converter (ADC).
However, Perron does address this limitation. Eiselt, Gurusami, and Perron are considered to be analogous to the present invention because they are related to optical time-domain reflectometer devices for optical fiber inspection.
Perron discloses the OTDR of claim 17, “wherein the means for receiving further comprises an analog-to-digital converter (ADC)” (Perron [0241] and fig. 17 disclose a detection assembly 1056 which comprise a light detector 1066 (such as a photodiode) that is in electrical communication with an analog to digital converter 1068, where the detected return light signal is converted from an electrical signal into a digital signal for data storage and processing and [0240] the returned light signal is a received backscatter signal from an optical fiber under test; the means for receiving is considered as any component which receives backscattered light, and thus the analog to digital converter along with the light detector [photodiode] are considered elements of the means for receiving).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Eiselt in view of Gurusami to incorporate wherein the means for receiving further comprises an analog-to-digital converter (ADC) as suggested by Perron for the advantage of providing an explicit means for storing and later processing backscatter data received by the avalanche photodiode (Perron [0241]).
Documents Considered but not Relied Upon
The following document(s) were considered but not relied up on for the rejection set forth in this action:
US 2013/0251363 A1 by Daniel M. Joffe et al. (herein after “Joffe”) – fig. 2 of Joffe discloses an OTDR system where an optical signal is obtained from fiber 15 that is routed simultaneously to two detectors 53 and 54 (i.e. photodiodes, see [0020]) which converts optical into an electrical signal that is sent to signal conditioning elements 56 and 57, where the signal conditioning elements condition the signal “e.g. amplified and filtered” – this also reads on “without modifying or adjusting optical values of the samples of the backscatter optical signal prior to the electrical samples related to the backscatter optical signal being sampled by the at least one element of the receiver” of claim 1 and similar limitations of claims 13 and 17. This concept is well known in the art.
US 10,135,531 B1 by Daniel M. Joffe et al. (herein after “Daniel”) is drawn to an OTDR system and method; fig. 3 directly discloses reflected and backscattered light from a fiber optic cable 14 being incident to an avalanche photodiode 120 and being fed to a transimpedance amplifier 122 before undergoing gain adjustments and being fed to an analog to digital converter – similar to Joffe, Daniel also reads on without modifying or adjusting optical values of the samples of the backscatter optical signal prior to the electrical samples related to the backscatter optical signal being sampled by the at least one element of the receiver” of claim 1 and similar limitations of claims 13 and 17. This concept is well known in the art.
Conclusion
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/JOSHUA M CARLSON/Examiner, Art Unit 2877
/TARIFUR R CHOWDHURY/Supervisory Patent Examiner, Art Unit 2877