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 .
Request for Continued Examination Under
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 11/26/2025 has been entered.
Response to Arguments
Claim Objections
With claim 2 amended and claim 11 canceled, the existing objections to the claims are withdrawn.
Rejections under 35 U.S.C. § 103
Applicant’s argument is that neither Lee nor Hotate teaches that the third modulator (identified with modulator 43 of Hotate) receives an oscillator signal, however, this argument is not persuasive. FIG. 6 of Hotate includes such an oscillator, oscillator 44, which paragraph 111 of Hotate describes as causing modulator 43 to shift the frequency of the light by, for example, about 11.26 GHz. Claim 1 remains rejected.
Since claim 1 is not allowable over the prior art, depending on claim 1 or relying on the same arguments as claim 1 does not grant allowability to other claims.
Claim Objections
Claims 21 and 23 are objected to because of the following informalities:
Claim 21 recites “wherein the third modulator configured to combine” rather than “wherein the third modulator is configured to combine”.
In claim 23, the claimed formula appears to have a typographical error. As shown in paragraphs 26 and 27 of the present disclosure and as known in the art, the imaginary part of a complex number should be multiplied by the imaginary unit, i, when calculating a complex amplitude.
Appropriate correction is required.
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.
Claim 21 is 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.
Claim 21 describes the signal paths in a way that is unclear and appears to be inconsistent with the disclosure. In particular, claim 21 appears to confuse the paths that the various signals take between the different devices that make up the claimed polarization pulling sensor. Claim 1, on which claim 21 depends, appears to be consistent with the embodiment shown in FIG. 1 of the present disclosure, in which a filter (embodied as filter 122) sends a lower sideband, also known in claim 1 as the probe signal, along two paths, a first path that goes through fiber under test 114, where polarization pulling occurs due to coupling with the pump pulses via Brillouin scattering, to the polarizing beam splitter, where part of the light is discarded and the rest is sent to the detector 136 and a second path in which the same optical signal (described in the disclosure as the local oscillator signal 126) is sent to the third modulator (embodied as AOM 134), generating the modulated probe signal, and combined with the light from the beam splitter to produce an interference signal on the detector 136. In contrast, claim 21 is drafted in a way that suggests that the amplified probe light from the polarizing beam splitter 132 is somehow going to AOM 134. It is unclear how that would fit in with the claimed invention as a whole. Claim 21 is interpreted in light of the specification that the third modulator is configured to use a local oscillator signal to generate the modulated probe signal and that the modulated probe signal is combined with a polarization pulled component of the probe signal (not necessarily combined by the third modulator).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1, 3, 6-10, 13, and 20-24 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lee (US Patent Publication 20210148736) in view of Hotate (Foreign Patent Publication JP-2016148661-A).
Regarding claim 1, Lee teaches a polarization pulling sensor comprising;
a first modulator configured to receive an optical beam and generate pump pulses (FIG. 2, third modulator 235);
a first amplifier configured to: receive the pump pulses from the first modulator, and amplify the pump pulses (FIG. 2, second optical amplifier 275);
a second modulator configured to receive the optical beam and to produce a plurality of sidebands based on the optical beam (FIG. 2, first modulator 220. Note that FIG. 2 is missing the reference number 220—the modulator in question is the component labeled “SSBM”.), wherein the sidebands are shifted by approximately a Brillouin frequency (paragraph 54 uses vB to describe the frequency shift. Paragraph 104 connects vB to a Brillouin frequency. Note also that one of ordinary skill in the art would have known that vB is a Brillouin frequency and that the phenomenon of stimulated Brillouin scattering depends on the use of two frequencies separated by a Brillouin frequency.), thereby producing a probe signal (FIG. 2, the modulated and filtered signal from first modulator 220 is labeled “Probe” in the figure);
a second amplifier configured to amplify the lower sideband (FIG. 2, first optical amplifier 270), thereby generating an amplified lower sideband (generating an amplified lower sideband is inherently the result of amplifying a lower sideband);
a fiber under test (FUT) configured to receive the amplified pump pulses generated by the first amplifier and the amplified lower sideband generated by the second amplifier (FIG. 2. Fiber under test 30);
a polarization pulling detector configured to: receive the amplified lower sideband (FIG. 2, photodetector 530), and
record an amplitude of the signal as a function of a probe frequency, thereby providing a measurement of a Brillouin gain spectrum, wherein a center of the Brillouin gain spectrum provides a measurement of a Brillouin frequency of the FUT (paragraph 21).
Lee does not explicitly teach that the sensor is configured to separate amplified probe light from background probe light; that the modulator that produces the lower sideband is split between a modulator that produces a plurality of sidebands and a separate filter to select a lower sideband (Lee integrates those two functions into one single sideband modulator, which produces the probe signal); the use of a beam splitter configured to receive the amplified lower sideband from the FUT and send light to the detector; a third modulator configured to receive an oscillator signal and modulate the probe signal using the oscillator signal, thereby providing a modulated probe signal; that the detector receives the modulated probe signal; nor that the signal detected is an interference signal.
In the same field of endeavor of Brillouin distributed optical fiber sensing, Hotate teaches that the sensor is configured to separate amplified probe light from background probe light (FIG. 6, the optical path from polarizing beam splitter 62b labeled as X polarized leaves the system, which separates it from light that stays in the system); the use of an optical modulator (FIG. 6, optical modulators 56a and 56b both modulate the frequency of one of optical inputs for the fiber under test.) separate from an optical filter (FIG. 6, tunable bandpass filter 60a, which removes unwanted frequency components, see paragraph 135); the use of a beam splitter configured to receive the amplified lower sideband from the FUT and send light to the detector (FIG. 6, polarizing beam splitter 62b, which sends light of one linear polarization state to the detector and rejects light of an orthogonal linear polarization state); a third modulator configured to receive an oscillator signal and modulate the probe signal using the oscillator signal, thereby providing a modulated probe signal (FIG. 6, SSB modulator 43, which is configured to produce a sideband at a frequency different from that of the probe beam and is used for heterodyne detection of the signal from the fiber under test and oscillator 44, which causes the modulator 43 to adjust the signal by, for example, 11.26 GHz (see paragraph 111)); that the detector receives the modulated probe signal (FIG. 6, the signal from modulator 43 makes its way to the balanced photodetector 19); and that the signal detected is an interference signal (FIG. 6, the y-polarized light from polarization controller 58e would interfere with the y-polarized light from polarization controller 58d).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin distributed optical fiber sensor of Lee with the separate modulator and filter, beam splitter, and additional modulator with oscillator of Hotate because a filter can remove unwanted frequency components; a beam splitter, especially a polarizing beam splitter, can be used to separate unwanted light from wanted light (see FIG. 6 of Hotate, wherein one of the polarization components of the light emerging from polarizing filter 62b, labeled X, exits the figure without being directed to a detector, separate from the Y-polarized light); and so as to enable heterodyne detection by shifting a frequency by an oscillator frequency, which can simplify the processing of the raw data (see paragraph 115 of Hotate).
Regarding claim 3, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described below).
Lee further teaches that the first amplifier and the second amplifier are Erbium-doped fiber amplifiers (EDFAs) (FIG. 2, the first and second optical fiber amplifiers 270 and 275 are labeled EDFA. Also see paragraph 75, final sentence).
Regarding claim 6, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described below).
Lee further teaches a first polarization controller configured to receive the amplified pump pulses from the first amplifier (FIG. 2, second polarization controller 255); and
a second polarization controller configured to receive the amplified lower sideband from the second amplifier (FIG. 2, first polarization controller 250).
However, Lee depicts the polarization controllers upstream of their respective modulators and amplifiers, so that the modulators and amplifiers receive polarized light rather than the polarization controllers receiving modulated and amplified light.
Given that modulators, optical fibers, and amplifiers can easily be chosen to maintain the polarization state of a pre-polarized optical signal, the design choice of whether to place the polarization controllers before or after those other components is not critical to the device of Lee, as modified by Hotate, or to the claimed invention. Mere rearrangement of parts usually does not patentably distinguish a claimed invention from the prior art.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin distributed optical fiber sensor of Lee, as modified by Hotate, by rearranging parts to place the polarization controllers after the modulators and amplifiers instead of before them.
Regarding claim 7, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 6 (as described below).
Neither Lee nor Hotate explicitly states that the first polarization controller is adjusted to maximize probe light reflected at the beam splitter to maximize a polarization pulling effect.
However, Lee does contemplate a variety of polarization angles of both the pump and the probe signals, including angles other than 0° and 90° (paragraph 74, final sentence). A person of ordinary skill in the art before the effective filing date of the claimed invention would have found it obvious to optimize, through routine experimentation, the angle of the first polarization controller in the device of Lee, as modified by Hotate, motivated to improve the signal to noise ratio of the Brillouin distributed optical fiber sensor and would have had a reasonable expectation of success.
Regarding claim 8, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 6 (as described below).
Neither Lee nor Hotate explicitly states that the second polarization controller is adjusted to minimize light reflected at the beam splitter, thereby discarding most of the probe light in the absence of a stimulated Brillouin scattering (SBS) interaction.
However, Lee does contemplate a variety of polarization angles of both the pump and the probe signals, including angles other than 0° and 90° (paragraph 74, final sentence).
A person of ordinary skill in the art before the effective filing date of the claimed invention would have found it obvious to optimize, through routine experimentation, the angle of the second polarization controller in the device of Lee, as modified by Hotate, motivated to improve the signal to noise ratio of the Brillouin distributed optical fiber sensor and would have had a reasonable expectation of success.
Regarding claim 9, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 6 (as described below).
Lee further teaches a first circulator configured to:
receive the amplified pump pulses from the first polarization controller and to pass the amplified pump pulses to the FUT, receive the amplified lower sideband from the FUT, and pass the amplified lower sideband to the beam splitter (FIG. 2, optical circulator 510).
Lee does not explicitly teach a second circulator configured to receive the amplified lower sideband from the second polarization controller and to pass the amplified lower sideband to the FUT, but does teach an optical isolator configured to receive the amplified lower sideband from the second polarization controller and to pass the amplified lower sideband to the FUT (FIG. 2, optical isolator 290).
When a circulator is configured, as claimed and as disclosed, to direct input from one of its ports (e.g., from the second polarization controller) to a second port (such as the FUT), direct input from the second port out of the optical system, and not direct any particular input back toward the first port (where any light passing through the second polarizer might get amplified by the second amplifier), then that circulator is being used in a manner equivalent to an optical isolator, which causes light entering a first port to exit a second, but does not cause light entering the second port to go out the first.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin distributed optical fiber sensor of Lee, as modified by Hotate, to use an optical circulator instead of an optical isolator, as either can equivalently direct probe light to the fiber under test without directing pump light from the fiber under test back to an amplifier, which could amplify it, potentially damaging optical components.
Regarding claim 10, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described below).
While Lee does not teach that the beam splitter is a polarizing beam splitter (PBS), Hotate does teach that the beam splitter is a polarizing beam splitter (PBS) (FIG. 6, polarizing beam splitter 62b).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to, while modifying the Brillouin distributed optical fiber sensor of Lee with the teachings of Hotate, use the same kind of beam splitter as Hotate used (a polarizing beam splitter), thereby having a reasonable expectation of successfully achieving the same result as Hotate in separating light of one polarization state to be discarded (labeled X by Hotate in FIG. 6) from an orthogonal polarization state to be detected (labeled Y by Hotate in FIG. 6) in the same manner as Hotate.
Regarding claim 13, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described below).
While Lee does not teach that the detector is configured to record, based on the amplified pump pulses and the modulated lower sideband, an amplitude of an interference signal as a function of probe frequency, thereby providing a measurement of a Brillouin gain spectrum, Hotate does teach that the detector is configured to record, based on the amplified pump pulses and the modulated lower sideband, an amplitude of an interference signal as a function of probe frequency, thereby providing a measurement of a Brillouin gain spectrum (paragraph 5).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to, while modifying the Brillouin distributed optical fiber sensor of Lee with the teachings of Hotate, to follow the example of Hotate by measuring the interference between the two lights of different frequencies used in the heterodyne detection means borrowed from Hotate for use in the combination in order to simplify the processing of the raw data.
Regarding claim 20, Lee teaches a polarization pulling sensor comprising;
a first modulator configured to receive an optical beam and generate pump pulses (FIG. 2, third modulator 235);
a first amplifier configured to: receive the pump pulses from the first modulator, and amplify the pump pulses (FIG. 2, second optical amplifier 275);
a first polarization controller configured to receive the amplified pump pulses from the first amplifier (FIG. 2, second polarization controller 255);
a second modulator configured to receive the optical beam and to produce a plurality of sidebands based on the optical beam (FIG. 2, first modulator 220. Note that FIG. 2 is missing the reference number 220—the modulator in question is the component labeled “SSBM”.), wherein the sidebands are shifted by approximately a Brillouin frequency (paragraph 54 uses vB to describe the frequency shift. Paragraph 104 connects vB to a Brillouin frequency. Note also that one of ordinary skill in the art would have known that vB is a Brillouin frequency and that the phenomenon of stimulated Brillouin scattering depends on the use of two frequencies separated by a Brillouin frequency.), thereby producing a probe signal (FIG. 2, the modulated and filtered signal from first modulator 220 is labeled “Probe” in the figure);
a second amplifier configured to amplify the lower sideband (FIG. 2, first optical amplifier 270), thereby generating an amplified lower sideband (generating an amplified lower sideband is inherently the result of amplifying a lower sideband);
a second polarization controller configured to receive the amplified lower sideband from the second amplifier (FIG. 2, first polarization controller 250), thereby generating an amplified lower sideband (generating an amplified lower sideband is inherently the result of amplifying a lower sideband);
a fiber under test (FUT) configured to receive the amplified pump pulses from the first polarization controller and the amplified lower sideband from the second polarization controller (FIG. 2. fiber under test 30);
a polarization pulling detector configured to: receive the amplified lower sideband (FIG. 2, photodetector 530),
record an amplitude of the signal as a function of a probe frequency, thereby providing a measurement of a Brillouin gain spectrum, wherein a center of the Brillouin gain spectrum provides a measurement of a Brillouin frequency of the FUT (paragraph 21).
However, Lee depicts the polarization controllers upstream of their respective modulators and amplifiers, so that the modulators and amplifiers receive polarized light rather than the polarization controllers receiving modulated and amplified light
Given that modulators, optical fibers, and amplifiers can easily be chosen to maintain the polarization state of a pre-polarized optical signal, the design choice of whether to place the polarization controllers before or after those other components is not critical to the device of Lee or to the claimed invention. Mere rearrangement of parts usually does not patentably distinguish a claimed invention from the prior art.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin distributed optical fiber sensor of Lee by rearranging parts to place the polarization controllers after the modulators and amplifiers instead of before them.
Lee does not explicitly teach that the sensor is configured to separate amplified probe light from background probe light; that the modulator that produces the lower sideband is split between a modulator that produces a plurality of sidebands and a separate filter to select a lower sideband (Lee integrates those two functions into one single sideband modulator, which produces the probe signal); the use of a beam splitter configured to receive the amplified lower sideband from the FUT and send light to the detector; a third modulator configured to receive an oscillator signal and modulate the probe signal using the oscillator signal, thereby providing a modulated probe signal; that the detector receives the modulated probe signal;; nor that the signal detected is an interference signal.
In the same field of endeavor of Brillouin distributed optical fiber sensing, Hotate teaches that the sensor is configured to separate amplified probe light from background probe light (FIG. 6, the optical path from polarizing beam splitter 62b labeled as X polarized leaves the system, which separates it from light that stays in the system); the use of an optical modulator (FIG. 6, optical modulators 56a and 56b both modulate the frequency of one of optical inputs for the fiber under test.) separate from an optical filter (FIG. 6, tunable bandpass filter 60a, which removes unwanted frequency components, see paragraph 135); the use of a beam splitter configured to receive the amplified lower sideband from the FUT and send light to the detector (FIG. 6, polarizing beam splitter 62b); a third modulator configured to receive an oscillator signal and modulate the probe signal using the oscillator signal, thereby providing a modulated probe signal (FIG. 6, SSB modulator 43, which is configured to produce a sideband at a frequency different from that of the probe beam and is used for heterodyne detection of the signal from the fiber under test and oscillator 44, which causes the modulator 43 to adjust the signal by, for example, 11.26 GHz (see paragraph 111)); that the detector receives the modulated probe signal (FIG. 6, the signal from modulator 43 makes its way to the balanced photodetector 19); and that the signal detected is an interference signal (FIG. 6, the y-polarized light from polarization controller 58e would interfere with the y-polarized light from polarization controller 58d).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin distributed optical fiber sensor of Lee with the separate modulator and filter, beam splitter, and additional modulator of Hotate because a filter can remove unwanted frequency components; a beam splitter, especially a polarizing beam splitter, can be used to separate unwanted light from wanted light (see FIG. 6 of Hotate, wherein one of the polarization components of the light emerging from polarizing filter 62b, labeled X, exits the figure without being directed to a detector, separate from the Y-polarized light); and so as to enable heterodyne detection by shifting a frequency by an oscillator frequency, which can simplify the processing of the raw data (see paragraph 115 of Hotate).
Neither Lee nor Hotate explicitly states that the first polarization controller is adjusted to maximize probe light reflected at the beam splitter to maximize a polarization pulling effect.
However, Lee does contemplate a variety of polarization angles of both the pump and the probe signals, including angles other than 0° and 90° (paragraph 74, final sentence). A person of ordinary skill in the art before the effective filing date of the claimed invention would have found it obvious to optimize, through routine experimentation, the angle of the first polarization controller in the device of Lee, as modified by Hotate, motivated to improve the signal to noise ratio of the Brillouin distributed optical fiber sensor and would have had a reasonable expectation of success.
Neither Lee nor Hotate explicitly states that the second polarization controller is adjusted to minimize light reflected at the beam splitter, thereby discarding most of the probe light in the absence of a stimulated Brillouin scattering (SBS) interaction.
However, Lee does contemplate a variety of polarization angles of both the pump and the probe signals, including angles other than 0° and 90° (paragraph 74, final sentence).
A person of ordinary skill in the art before the effective filing date of the claimed invention would have found it obvious to optimize, through routine experimentation, the angle of the second polarization controller in the device of Lee, as modified by Hotate, motivated to improve the signal to noise ratio of the Brillouin distributed optical fiber sensor and would have had a reasonable expectation of success.
Regarding claim 21, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described above).
Lee does not explicitly teach that the third modulator is configured to combine a polarization pulled component of the probe signal with a local oscillator signal to generate the modulated probe signal.
In the same field of endeavor of Brillouin distributed optical fiber sensing, Hotate teaches that the third modulator is configured to combine a polarization pulled component of the probe signal with a local oscillator signal to generate the modulated probe signal (FIG. 6, the local oscillator signal is the reference signal modulated by modulator 43, which is combined with the light not rejected by polarizing beam splitter 62b). By combining the modulated signal and the light from the fiber under test in a particular manner, Hotate is able to perform heterodyne detection, simplifying the processing of the raw data produced while also getting a good signal-to-noise ratio.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin distributed optical fiber sensor of Lee, as modified by Hotate, with particular beam paths taught by Hotate to enable heterodyne detection in order to gain the benefit of simplifying the processing of the raw data produced while also getting a good signal-to-noise ratio.
Regarding claim 22, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described above).
While Lee does not teach that the polarization pulling detector is further configured to detect an amplitude and phase of probe light in the probe signal using heterodyne detection based on the modulated probe signal, Hotate does teach that the polarization pulling detector is further configured to detect an amplitude and phase of probe light in the probe signal using heterodyne detection based on the modulated probe signal (FIG. 6, the reference signal coming from modulator 43, corresponding to the claimed modulated probe signal, is used in heterodyne detection techniques using optical heterodyne receiver 19. Optical heterodyne detection is a way to configure a detector to detect an amplitude and phase of a signal (see Paschotta 1 (Non-Patent Literature “Optical Modulators”), especially section “Temporal Coherence Issues”, paragraph 2, last two sentences and note that Hotate uses a single light source)). By using phase and amplitude sensitive heterodyne detection techniques, Hotate is able to simplify the processing of the raw data produced while also getting a good signal-to-noise ratio.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin distributed optical fiber sensor of Lee, as modified by Hotate, with the phase and amplitude sensitive heterodyne detection of Hotate in order to gain the benefit of simplifying the processing of the raw data produced while also getting a good signal-to-noise ratio.
Regarding claim 23, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described above).
Lee further teaches a system in which the amplitude of the interference signal can be estimated as ASBS = (ISBS - IREF) + i (QSBS - QREF), wherein SBS stands for stimulated Brillouin scattering, ISBS is the real part of a field when an SBS pump is present, IREF is the real part of the field without the pump, QSBS is the imaginary part of the field when the SBS pump is present, and QREF is the imaginary part of the field without the pump (FIG. 2, by using lock-in amplifier 540, the part of the signal that does not depend on the pulses can be ignored (i.e., subtracted out) while the part of the signal with the desired part of the signal amplified).
Regarding claim 24, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described above).
While Lee and Hotate do not explicitly teach that the probe is y-polarized, wherein the beam splitter is further configured to split the amplified lower sideband into a y-polarized rejected probe and an x-polarized pulled probe, and wherein the polarization pulling detector is configured to receive the x-polarized pulled probe from the beam splitter, as Lee does not use specific names for polarization directions (such as x and y) and Hotate uses Y as the name of the polarization state that is not rejected (FIG. 6, polarizing beam splitter 62b) rather than x, it should be noted that neither the limitations of this claim nor conventions known in the art impose an unambiguous way of defining which axis transverse to beam propagation should be labeled x and which axis should be labeled y. As a result, the choice of which axis is x and which is y is arbitrary.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to label the polarization axes of the Brillouin distributed optical fiber sensor of Lee, as modified by Hotate, in the arbitrary manner claimed without further modifying the device itself.
Even if the unlabeled axis of Lee and the y axis of Hotate are assumed to be distinct from the x axis of the claim, mere rearrangement of parts is generally not considered sufficient to patentably distinguish over the prior art (see MPEP 2144.04 VI C), so it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin distributed optical fiber sensor of Lee, as modified by Hotate, by rotating the device as a whole to align it with the claimed coordinate system, merely rearranging the parts without changing their functions or how they interconnect.
Claim(s) 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lee (US Patent Publication 20210148736) in view of Hotate (Foreign Patent Publication JP2016148661-A) as applied to claim 1 above, and further in view of Paschotta 2 (Non-Patent Literature “Optical Modulators”).
Regarding claim 2, Lee, as modified by Hotate, teaches or renders obvious the (as described below).
Neither Lee nor Hotate explicitly states that the first or third modulators should be acousto-optic modulators (AOMs).
In the same field of endeavor of modulating optical beams, Paschotta 2 does teach the use of AOMs (page 2, first bullet point), specifically for use in switching the amplitude of a laser beam (such as in turning a continuous beam into pulses) and shifting optical frequencies (such as to produce sidebands or shift the frequency of a lower sideband).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have designed the Brillouin distributed optical fiber sensor of Lee, as modified by Hotate, choosing a type of optical modulator appropriate to the tasks at hand, such as carving pulses from a continuous beam or modulating a frequency to produce or change the frequency of a sideband, rather than choosing a different type of optical modulator that may be either equivalent or worse for those tasks.
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lee (US Patent Publication 20210148736) in view of Hotate (Foreign Patent Publication JP2016148661-A) as applied to claim 1 above, and further in view of Newport (Non-Patent Literature “Technical Note: Electro-Optic Modulator FAQs”).
Regarding claim 4, Lee, as modified by Hotate, teaches or renders obvious the polarization pulling sensor of claim 1 (as described below).
Neither Lee nor Hotate explicitly states that the second modulator is an electro-optic modulator (EOM).
In the same field of endeavor of modulating optical beams, Newport does teach the use of EOMs to generate sidebands (page 5).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have designed the Brillouin distributed optical fiber sensor of Lee, as modified by Hotate, choosing a type of optical modulator suitable for the intended purpose of the optical modulator instead of choosing a different type of sideband-creating optical modulator less commonly used in the art.
Claim(s) 14-17 and 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lee (US Patent Publication 20210148736) in view of Hotate (Foreign Patent Publication JP-2016148661-A) and Remer (Non-Patent Literature “High sensitivity and high-specificity biomechanical imaging by stimulated Brillouin scattering microscopy”).
Regarding claim 14, Lee teaches a polarization pulling sensor comprising;
a first modulator configured to receive an optical beam and generate pump pulses (FIG. 2, third modulator 235);
a first amplifier configured to: receive the pump pulses from the first modulator, and amplify the pump pulses (FIG. 2, second optical amplifier 275);
a second modulator configured to receive the optical beam and to produce a plurality of sidebands based on the optical beam (FIG. 2, first modulator 220. Note that FIG. 2 is missing the reference number 220—the modulator in question is the component labeled “SSBM”.), wherein the sidebands are shifted by approximately a Brillouin frequency (paragraph 54 uses vB to describe the frequency shift. Paragraph 104 connects vB to a Brillouin frequency. Note also that one of ordinary skill in the art would have known that vB is a Brillouin frequency and that the phenomenon of stimulated Brillouin scattering depends on the use of two frequencies separated by a Brillouin frequency.), thereby producing a probe signal (FIG. 2, the modulated and filtered signal from first modulator 220 is labeled “Probe” in the figure);
a second amplifier configured to amplify the lower sideband (FIG. 2, first optical amplifier 270), thereby generating an amplified lower sideband (generating an amplified lower sideband is inherently the result of amplifying a lower sideband);
a sample under test configured to receive the amplified pump pulses generated by the first amplifier and the amplified lower sideband generated by the second amplifier (FIG. 2. Fiber under test 30);
a polarization pulling detector configured to: receive the amplified lower sideband (FIG. 2, photodetector 530),
record an amplitude of the signal as a function of a probe frequency, thereby providing a measurement of a Brillouin gain spectrum, wherein a center of the Brillouin gain spectrum provides a measurement of a Brillouin frequency of the sample under test (paragraph 21).
Lee does not explicitly teach that the sensor is configured to separate amplified probe light from background probe light; that the modulator that produces the lower sideband is split between a modulator that produces a plurality of sidebands and a separate filter to select a lower sideband (Lee integrates those two functions into one single sideband modulator, which produces the probe signal); the use of a beam splitter configured to receive the amplified lower sideband from the sample under test and send light to the detector; a third modulator configured to receive an oscillator signal and modulate the probe signal using the oscillator signal, thereby providing a modulated probe signal; that the detector receives the modulated probe signal; nor that the signal detected is an interference signal.
In the same field of endeavor of Brillouin scattering measurements, Hotate teaches that the sensor is configured to separate amplified probe light from background probe light (FIG. 6, the optical path from polarizing beam splitter 62b labeled as X polarized leaves the system, which separates it from light that stays in the system); the use of an optical modulator (FIG. 6, optical modulators 56a and 56b both modulate the frequency of one of optical inputs for the fiber under test.) separate from an optical filter (FIG. 6, tunable bandpass filter 60a, which removes unwanted frequency components, see paragraph 135); the use of a beam splitter configured to receive the amplified lower sideband from the FUT and send light to the detector (FIG. 6, polarizing beam splitter 62b); a third modulator configured to receive an oscillator signal and modulate the probe signal using the oscillator signal, thereby providing a modulated probe signal (FIG. 6, SSB modulator 43, which is configured to produce a sideband at a frequency different from that of the probe beam and is used for heterodyne detection of the signal from the sample under test and oscillator 44, which causes the modulator 43 to adjust the signal by, for example, 11.26 GHz (see paragraph 111)); that the detector receives the modulated probe signal (FIG. 6, the signal from modulator 43 makes its way to the balanced photodetector 19); and that the signal detected is an interference signal (FIG. 6, the y-polarized light from polarization controller 58e would interfere with the y-polarized light from polarization controller 58d).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin sensor of Lee with the separate modulator and filter, beam splitter, and additional modulator of Hotate because a filter can remove unwanted frequency components; a beam splitter, especially a polarizing beam splitter, can be used to separate unwanted light from wanted light (see FIG. 6 of Hotate, wherein one of the polarization components of the light emerging from polarizing filter 62b, labeled X, exits the figure without being directed to a detector, separate from the Y-polarized light); and so as to enable heterodyne detection by shifting a frequency by an oscillator frequency, which can simplify the processing of the raw data (see paragraph 115 of Hotate).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin sensor of Lee, as modified by Hotate, to use a microscopy apparatus like that of Remer instead of an optical fiber in order to probe the properties of a small region of a sample rather than the length of an optical fiber.
Regarding claim 15, Lee, as modified by Hotate and Remer, teaches or renders obvious the polarization pulling sensor of claim 14 (as described below).
Lee does not explicitly teach a microscopy apparatus comprising any particular parts; however, Remer does teach that the microscopy apparatus comprises: a first microscope objective configured to receive the amplified pump pulses and to focus the amplified pump pulses on a sample (FIG. 1c, the objective lens depicted just below the sample stage. The Methods section describes it as an objective lens on the fifth page of the provided pdf, about halfway down the left-hand column, directly to the left of “Preparation of the C. elegans samples.”); and
a second microscope objective configured to receive the amplified lower sideband and to focus the amplified lower sideband on the sample (FIG. 1c, the objective lens just above the sample stage. The Methods section describes it as an objective lens on the fifth page of the provided pdf, about halfway down the left-hand column, directly to the left of “Preparation of the C. elegans samples.”).
As is common for an optical microscopy apparatus, Remer accomplishes the task of focusing light onto a particular point on a sample and gathering light from that point in the sample through the use of a microscopy objective. As there are two distinct lights to be focused onto the sample (pump light and probe light) and then be gathered on the other side in order to perform stimulated Brillouin scattering techniques(based on optical fiber or on microscopy), two microscope objectives are called for.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the stimulated Brillouin scattering microscope of Lee, as modified by Remer and Hotate, by using a pair of microscope objectives in the microscopy apparatus, motivated by the goal of performing Brillouin scattering experiments requiring the application and collection of focused light on both sides of the sample.
Regarding claim 16, Lee, as modified by Hotate and Remer, teaches or renders obvious the polarization pulling sensor of claim 14 (as described below).
Lee further teaches a first polarization controller configured to polarize the amplified pump pulses from the first amplifier (FIG. 2, second polarization controller 255); and
a second polarization controller configured to polarize the amplified lower sideband from the second (FIG. 2, first polarization controller 250).
However, Lee depicts the polarization controllers upstream of their respective modulators and amplifiers, so that the modulators and amplifiers receive polarized light rather than the polarization controllers receiving modulated and amplified light.
Given that modulators, optical fibers, and amplifiers can easily be chosen to maintain the polarization state of a pre-polarized optical signal, the design choice of whether to place the polarization controllers before or after those other components is not critical to the device of Lee, as modified by Remer and Hotate, or to the claimed invention. Mere rearrangement of parts usually does not patentably distinguish a claimed invention from the prior art.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin sensor of Lee, as modified by Remer and Hotate, by rearranging parts to place the polarization controllers after the modulators and amplifiers instead of before them.
Regarding claim 17, Lee, as modified by Hotate and Remer, teaches or renders obvious the polarization pulling sensor of claim 16 (as described below).
Lee as modified by Remer and Hotate fail to explicitly state that the first polarization controller is adjusted to maximize probe light reflected at the beam splitter to maximize a polarization pulling effect and that the second polarization controller is adjusted to minimize light reflected at the beam splitter, thereby discarding most of the probe light in the absence of a stimulated Brillouin scattering (SBS) interaction.
However, Lee does contemplate a variety of polarization angles of both the pump and the probe signals, including angles other than 0° and 90° (paragraph 74, final sentence). A person of ordinary skill in the art before the effective filing date of the claimed invention would have found it obvious to optimize, through routine experimentation, the angles of the first and second polarization controllers in the device of Lee, as modified by Remer and Hotate, motivated to improve the signal to noise ratio of the Brillouin sensor and would have had a reasonable expectation of success.
Regarding claim 19, Lee, as modified by Hotate and Remer, teaches or renders obvious the polarization pulling sensor of claim 16 (as described below).
Lee further teaches a first circulator configured to:
receive the amplified pump pulses from the first polarization controller and to pass the amplified pump pulses to the sample under test, receive the amplified lower sideband from the sample under test, and pass the amplified lower sideband to the beam splitter (FIG. 2, optical circulator 510).
Lee does not explicitly teach a second circulator configured to receive the amplified lower sideband from the second polarization controller and to pass the amplified lower sideband to the sample under test, but does teach an optical isolator configured to receive the amplified lower sideband from the second polarization controller and to pass the amplified lower sideband to the sample under test (FIG. 2, optical isolator 290).
When a circulator is configured, as claimed and as disclosed, to direct input from one of its ports (e.g., from the second polarization controller) to a second port (such as the sample under test), direct input from the second port out of the optical system, and not direct any particular input back toward the first port (where any light passing through the second polarizer might get amplified by the second amplifier), then that circulator is being used in a manner equivalent to an optical isolator, which causes light entering a first port to exit a second, but does not cause light entering the second port to go out the first.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Brillouin microscope of Lee, as modified by Hotate and Remer, to use an optical circulator instead of an optical isolator, as either can equivalently direct probe light to the microscopy apparatus without directing pump light from the microscopy apparatus back to an amplifier, which could amplify it, potentially damaging optical components.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PAUL D SCHNASE whose telephone number is (703)756-1691. The examiner can normally be reached Monday - Friday 8:30 AM - 5:00 PM ET.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Tarifur Chowdhury can be reached at (571) 272-2287. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/PAUL SCHNASE/ Examiner, Art Unit 2877
/TARIFUR R CHOWDHURY/ Supervisory Patent Examiner, Art Unit 2877