Office Action 2: Notice of Allowance (2025-02-27)

CLAIMS:
AMENDMENTS TO THE CLAIMS

The following listing of claims replaces all previous listings of claims in the instant application.

1\. (Currently Amended) An apparatus suitable for optical coherence tomography (OCT) scanning of a subject, the apparatus comprising:at least one source for providing a first signal and a reference signal;
a photonics integrated circuit comprising:
(i) a first path for receiving a reflected first signal, reflected from the subject;
(ii) a second path for coupling the reflected first signal to the reference signal to provide an interference signal, and
(iii) a variable delay for varying an optical path length of one of the reference signal and the first signal to match the optical path length of the reference signal to an optical path length of the reflected first signal, wherein the variable delay comprises a series of binary switches and a series of path elements of different lengths of L
wherein the series of path elements comprises lengths of L up to 2NL, where N is \[\[an\]\] apositive integer; anda detector for analyzing and detecting the interference signal.

2\. (Cancelled)

3\. (Cancelled)
4\. (Previously Presented) The apparatus of claim 1, wherein the variable delay is a binary delay implementing a delay, in steps of L, of 0 to (2x2N-1)L.

5\. (Previously Presented) The apparatus of claim 4, wherein the variable delay has N delay path elements and N+1 binary switches, one binary switch before each delay path element, to selectively switch between a direct path or the delay path element, and one binary switch at the

output to selectively switch from the direct path or a final delay path element to an output of the variable delay.

6\. (Previously Presented) The apparatus of claim 4, wherein the switches are two-way multiplexing or demultiplexing switches.

7\. (Previously Presented) The apparatus of claim 1, wherein the variable delay acts on the reference signal.

8\. (Previously Presented) The apparatus of claim 1, wherein one of the paths of different lengths includes a tunable labyrinth with integrated phase shifter.

9\. (Previously Presented) The apparatus of claim 1, wherein the at least one source comprises a broadband light source and the detector for analyzing and detecting the interference signal comprises a spectrometer.

10\. (Previously Presented) The apparatus of claim 9, wherein the spectrometer is implemented as one of an arrayed waveguide grating, AWG, a ring bus, a ring fan-out, a binary asymmetric Mach-Zehnder interferometer (AMZI), or an AMZI fan out.

11\. (Previously Presented) The apparatus of claim 1, wherein the at least one source a swept laser source and the detector comprises a point photodetector.

12\. (Previously Presented) The apparatus of claim 1, wherein the at least one source comprises a beam-splitter, and wherein the beam-splitter beam-splits the first signal.

13\. (Previously Presented) The apparatus of claim 1, wherein the second path is a 2 x 2 coupler, and wherein the 2 x 2 coupler is one of a directional coupler, a multimode interferometer or a Mach-Zender interferometer.

14\. (Previously Presented) The apparatus of claim 1, wherein the photonic integrated circuit comprises:

a first path for guiding the first signal to a set of imaging optics to the subject and for guiding reflected light from the subject back through the set of imaging optics to the second path for coupling the reflected first signal to the reference signal to provide an interference signal; and
a second path for guiding the reference signal to a reflector and back to the second path for coupling the reflected first signal to the reference signal to provide an interference signal.

15\. (Previously Presented) The apparatus of claim 14, wherein the first and second paths comprise polarization-maintaining fibers for maintaining polarization of the first signal and the reference signal respectively.

16\. (Previously Presented) The apparatus of claim 1, further comprising an output image processor for remote viewing of the analyzed interference signal an on-chip control unit for remote control of the variable delay.

17\. (Currently Amended) A method suitable for performing an optical coherence tomography (OCT) scan, the method comprising:providing a first signal provided by a light source;
providing a reference signal;
reflecting the first signal from a subject and coupling the reflected first signal to the reference signal to provide an interference signal;
adjusting a delay of one of the reference signal and the first signal by a variable delay to match an optical path length of the reference signal to an optical path length of the reflected first signal, wherein the step of adjusting comprises selecting between paths of different lengths, wherein the variable delay comprises a series of binary switches and a series of different selectable path elements, wherein the series of path elements comprise lengthsof L
up to \[\[2NL\]\] 2NL, where N is \[\[an\]\] a positive integer; andanalyzing the interference signal.

18\. (Cancelled)
Filing Date: May 12, 2023

19\. (Cancelled)

20\. (New) The apparatus of claim 17 wherein the minimum value of N is 2.

21\. (New) The apparatus of claim 1 wherein the minimum value of N is 2.

OFFICE 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 .
The following is an examiner’s statement of reasons for allowance: No prior arts of record alone or in combination discloses the following:
“adjusting a delay of one of the reference signal and the first signal by a variable delay to match an optical path length of the reference signal to an optical path length of the reflected first signal, wherein the step of adjusting comprises selecting between paths of different lengths, wherein the variable delay comprises a series of binary switches and a series of different selectable path lengths, wherein the series of path elements comprise lengths of L, 2L, etc. up to 2NL, where N is a positive integer”
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee.  Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”

APPLICANT REBUTTAL: REMARKS
By this paper, Claims 1 and 17 have been amended, Claims 18 and 19 have been cancelled, and new Claims 20 and 21 have been added. Support for these amendments can be found at least in paragraphs [0064] and [0067] of the published application, as well as elsewhere throughout the specification and claims as originally filed. No new matter has been added by these amendments. Claims 1, 4-17, 20 and 21 are pending and presented for examination.
Discussion of Rejection of Claims under 35 U.S.C.
§
The Office Action rejected Claims 1 and 5-19 under 35 U.S.C. § 112(b) as allegedly being indefinite.
By this paper, Claims 18 and 19 have been cancelled, rendering the rejection of these claims moot. Claims 1 and 17 have been amended to, among other amendments, remove the term "etc."
With respect to the feature of "the reflected first signal" in Claim 14, Applicant notes that this term has antecedent basis in at least line 5 of Claim 1. With respect to the feature "the analysed interference signal," Applicant notes that this term has antecedent basis at least in the recitation in line 15 of Claim 1 that the detector is for analyzing and detecting the interference signal. With respect to the feature of "the path elements" in Claim 17 as previously pending, Applicant notes that there was antecedent basis for the term earlier in Claim 17 as previously pending, and notes that Claim 17 has been further amended while providing antecedent basis for the recited features.
In view of these amendments, Applicant respectfully requests reconsideration and withdrawal of the rejections of the pending claims under 35 U.S.C. § 112(b). If further amendments are required, the Examiner is respectfully invited to contact the undersigned to discuss, in the interest of compact prosecution.
Discussion of Rejection of Claims under 35 U.S.C.
§
Claims 1, 4, 5, 7, 9, and 12-17 stand rejected under 35 U.S.C. § 103 as allegedly being unpatentable over U.S. Patent Application Publication No. 2014/0376000 by Swanson et al. (hereinafter "Swanson") in view of U.S. Patent Application Publication No. 2017/0227399 by Hu et al. (hereinafter "Hu").
The Office Action states that Claim 6 is rejected under 35 U.S.C. § 103 as allegedly being unpatentable over Swanson in view of U.S. Patent Application Publication No. 2007/0237524 by Gerstel et al. (hereinafter "Gerstel"). Applicant understands that, as Claim 6 indirectly depends from Claim 1, the Office Action intended to reject Claim 6 as unpatentable over Swanson in view of Hu and Gerstel, and responds accordingly.
Similarly, the Office Action states that Claim 10 is rejected under 35 U.S.C. § 103 as allegedly being unpatentable over Swanson in view of U.S. Patent Application Publication No. 2017/0366880 by Garcia et al. (hereinafter "Garcia"). Applicant understands that, as Claim 6 indirectly depends from Claim 1, the Office Action intended to reject Claim 10 as unpatentable over Swanson in view of Hu and Garcia, and responds accordingly.
Similarly, the Office Action states that Claim 11 is rejected under 35 U.S.C. § 103 as allegedly being unpatentable over Swanson in view of U.S. Patent Application Publication No. 2017/0238798 by Isogai et al. (hereinafter "Isogai"). Applicant understands that, as Claim 11 depends from Claim 1, the Office Action intended to reject Claim 11 as unpatentable over Swanson in view of Hu and Isogai, and responds accordingly.
Claims 18 and 19 stand rejected under 35 U.S.C. § 103 as allegedly being unpatentable over Swanson in view of U.S. Patent Application Publication No. 2020/0116489 by Wang et al. (hereinafter "Wang").
For the reasons set forth below, Applicant respectfully submits that the claims as currently pending are patentable over the cited combinations.
Law of Obviousness
To support a finding of "obviousness, the Examiner must show that each and every limitation of the claim is described or suggested by the prior art or would have been obvious based on the knowledge of those of ordinary skill in the art." Ex parte Newcomb, Bd. of Pat. App. and Int. (March 31, 2008), citing In re Fine, 837 F.2d 1071, 1074 (Fed. Cir. 1988); see also CFMT, Inc. v. Yieldup Int'l Corp., 349 F.3d 1333, 1342 (Fed. Cir. 2003) ("[O]bviousness requires a suggestion of all the elements in a claim."). Moreover, "rejections on obviousness grounds cannot be sustained by mere conclusory statements; instead, there must be some articulated reasoning with some rational underpinning to support the legal conclusion of obviousness." In re Kahn, 441
F.3d 977, 988 (Fed. Cir. 2006) (quoted with approval in KSR Int'l Co. v. Teleflex Inc., 127 S. Ct. 1727, 1741 (2007)).
Discussion of Independent Claims
Although Applicant does not necessarily agree with the Examiner's rejection of Claim 1 as previously pending, Applicant has by this paper amended Claim 1 to emphasize certain distinctions over the cited art, solely in the interest of advancing prosecution. As amended, Claim
1 recites:
An apparatus suitable for optical coherence tomography (OCT) scanning of
a subject, the apparatus comprising:
at least one source for providing a first signal and a reference signal;
a photonics integrated circuit comprising:
(i) a first path for receiving a reflected first signal, reflected from the subject;
(ii) a second path for coupling the reflected first signal to the reference signal to provide an interference signal, and
(iii) a variable delay for varying an optical path length of one of the reference signal and the first signal to match the optical path length of the reference signal to an optical path length of the reflected first signal, wherein the variable delay comprises a series of binary switches and a series of path elements of different lengths of L wherein the series of path elements comprises lengths of L up to 2NL, where N is a positive integer;
and
a detector for analyzing and detecting the interference signal.
In making a ground of rejection of Claim 1, the Office Action states that it would have been obvious to combine Swanson and Hu by "using a series of binary switches path elements of L, 2L, etc. up to 2NL, where N is an integer and wherein the variable delay is a binary delay implementing a delay, in steps of L, of 0 to (2x2N-1):; a cascade of optical switches to increase the tuning range, also referred to as the dynamic range) of optical path length differences and increasing the optical path length differences can increase the resolution of the spectrometer [see 0043]." Office Action, at page 5. For the reasons set forth below, Applicant respectfully disagrees.
Swanson
discloses designs, systems and methods directed towards Optical Coherence Tomography (OCT), employing one or more photonic integrated circuits (PICs). See Swanson, at Abstract. In contrast,
Hu
discloses apparatus, systems and methods that are generally related to Fourier Transform Spectroscopy. See Hu, at para. [0006]. Hu makes no reference to OCT.
Combining apparatus, systems and methods for Fourier Transform Spectroscopy with designs, systems and methods for OCT would not be obvious to a person having ordinary skill in the art of OCT or to a person having ordinary skill in the art of PICs.
The skilled person would not combine Swanson and Hu because while they are documents dealing with optical technology, the optical technologies involved in each document are very different with different end use applications.
Furthermore, even if the skilled person were to combine Swanson and Hu, they would still not arrive at Claim 1 as previously presented and as currently amended for the reasons set forth below.
Applicant notes, for purposes of this argument that while L, is simply referred to as L in the present patent application, it is referred to as L, in this response to avoid confusion with the L used in Hu, which is different and should not be conflated with the L described in the present application.
Amended claim 1 of the present application further clarifies that the first two (shortest) path elements are LP and 2LP. Hu discusses "variable" and "reference" optical path lengths which are relevant for the purposes of the first and second interference arms of Hu, discussed in turn below.
The first interference arm of Hu
To replicate the same behaviour of present claim 1 in Hu, i.e. to make the second "variable" path element twice the length of the first, requires 2(L + 20AL) = L + 22AL. Solving this returns AL = L/2.
Hu describes that AL/L is about 0.01 to 0.3. See Hu, at claim 8. As shown above, AL/L = 0.5 is required to achieve "variable" waveguide lengths equal to L, and 2Lp. Therefore, the range of values given by Hu for AL/L are
unsuitable
for OCT.
The second interference arm of Hu
Hu describes that the length of the mth "variable" waveguide in the second interference arm is L - 22-m1AL, where m=1, 2, ..., j/2. See Hu, at claims 5 and 7.
If one were to use only the second interference arm, which one should not, then it is only possible to avoid unphysical "variable" path lengths if it is configured to generate "variable" path lengths that increase with m. To do this, one must use a negative value of AL. Choosing AL =
-L/2 is necessary to ensure the second "variable" path element is twice the length of the first "variable" path element.
AL/L = -0.5 is also outside the range of values given by claim 8 of Hu for AL/L. Therefore, the range of values given by Hu for AL/L remain
unsuitable
for OCT.
Even if the first or second interference arms of Hu were in any way usable for OCT, which they are not, each interference arm can only include "variable" waveguides that are longer or shorter than the "reference" waveguides, as the length of each "variable" waveguide is dependent on the length of the corresponding "reference" waveguide. See Hu, at claims 3-7.
In the disclosed technology, the lengths of the "reference" waveguide and the "variable" waveguide are independent, and the tuneable switches can be set such that the default path is through the "reference" waveguide. See Publication, at para. [0070].
Thus, embodiments of the technology disclosed in the present patent application could be configured such that half of the "variable" waveguides are shorter than each "reference" waveguide and half of the "variable" waveguides are longer than each "reference" waveguide. This means the default path would be longer than the shortest total delay path and shorter than the longest total delay path. This means the average time to match the total delay path to the sample path length will be less than if the one of the interference arms from Hu were to be used, where the default path of an interference arm can only ever be the longest or the shortest total delay path.
More specifically, Hu would, on average, take twice as long to match the path lengths compared to embodiments of the technology disclosed in the present patent application, when the embodiments of the technology disclosed in the present patent application are configured such that the length of the default path sits exactly halfway between the shortest total delay path and the longest total delay path. Therefore, the embodiments of the technology disclosed in the present patent application are neither identically disclosed or obvious in light of Hu, whether or not this is taken in combination with Swanson.
Claim 1, as currently pending, is therefore non-obvious over a combination of Swanson and Hu. As Claim 17 recites certain features similar to those discussed above with respect to Claim
1, Applicant respectfully submits that independent Claim 17, as currently pending, is also non- obvious over a combination of Swanson and Hu.
Further Explanation of Unsuitability of Hu for OCT
In addition to the reasons above, Applicant respectfully notes that there are numerous additional reasons why the skilled person would not combine Swanson with Hu. These additional reasons include, wavelength incompatibility, signal destruction from  detectors, and the interference patterns of Hu being incompatible with OCT, each of which are discussed in term below.
Wavelength Incompatability
Hu provides an example operational wavelength of 1577.5 nm, for an on-chip spectrum analyzer covering the entire C and L bands (1530-1625 nm). See Hu, at para. [0077]. These wavelengths are unsuitable for OCT applications, example wavelengths for which are 840 nm (as mentioned in paragraph [0006] of the present patent application) or 1310 nm (as mentioned in paragraph [0045 of Swanson]). Therefore, Hu and Swanson cannot be combined to produce the disclosed technology embodied in the present patent application as Hu cannot be used for OCT.
Signal Destruction from Sensors
Even if the unsuitability of the Hu wavelengths could be overlooked, which they cannot, Hu's claim 1 (and so, by extension, claims 2-7), includes "a detector, in optical communication with the first interference arm and the second interference arm, to detect interference of the first portion of the incident light from the first interference arm and the second portion of the incident light from the second interference arm." The process of detection destroys the optical signal, so combining the disclosure of Hu with the variable delay of Swanson would render the invention disclosed in Swanson no longer able to perform OCT.
Generation of Interference Patterns
Even one were to ignore the presence of the detectors in Hu, which one cannot, the invention disclosed in Hu first splits the incident light into a first portion and a second portion, before passing the first portion through a first interference arm and the second portion through a
second interference arm. The first interference arm and the second interference arm are of different configurations such that there is an optical path length difference between the two. Finally, the first interference arm and the second interference arm are coupled to a beam combiner. See Hu, at claims 1-7, Abstract, and paras. [0008], [0023], 0029], and [0087]-[0094]. This generates interference patterns by design See Hu, at Abstract and para. [0023].
In OCT, interference patterns generated by the optical setup itself, rather than the sample, are a source of optical noise and are therefore undesirable. Optical noise obscures the interference patterns generated using light from the subject and so degrades the quality of the image. The use of the splitter in Hu, combined with changes in the optical path length difference between the two interference arms, means such degradation would be catastrophic and unavoidable, rendering the system unable to perform OCT.
Even if one were to ignore the issue of optical noise in Hu, which one cannot, the Office Action notes that Hu discloses "a cascade of optical switches to increase the tuning range (also referred to as the dynamic range) of optical path length differences and increasing the optical path length differences can increase the resolution of the spectrometer [see 0043]". Paragraph [0053] of Hu, and in particular equation (3), supports the Office Action's point that the system disclosed in Hu has a spectral resolution that can be improved by increasing the number of optical switches. Hu also discloses that the trade-off between spectral resolution, device footprint, and power consumption is a challenge and that lower spectral resolutions are undesirable (see para. [0005]), and that their invention offers superior spectral resolution with a compact footprint (see paras. [0026], [0051]). Therefore, the optimal implementation of Hu is the one that provides the highest spectral resolution. The implementation that provides the highest spectral resolution is the one that has the greatest number of optical switches.
However, embodiments of the disclosed technology require the optical path length of the reference signal and the optical path length of the reflected first signal to be "matched." See Publication, at Abstract, claim 1, claim 17, and paras. [0005], [0011], [0019], [0048], [0065]. The present specification also describes that matching the reference arm length to the sample path length is a problem (see para. [0007]), that the signals will not interfere as required unless the delay of the reference signal path is matched to the target signal path to within one coherence length (see para. [0044]), and that matching these paths will increase the clarity of resultant images (see para.
[0045]). The present specification states that peak interference occurs when the two path lengths match ([0044]). Therefore, the skilled person reading the present patent application would understand to try to create the closest match between the two path lengths. This is contrary to the disclosure of Hu, as discussed below.
Increasing the number of optical switches increases the minimum length of the reference signal path, as each optical switch has to be of finite length. This means that maximising the number of optical switches to provide the optimal implementation described in Hu will eventually increase the minimum length of the reference signal path of the present patent application to the point where it is greater than the length of the target signal path. This difference will be greater than one coherence length, as maximising the spectral resolution requires the number of optical switches to be increased indefinitely (see equation (3) in [0053] of Hu). Therefore, the optimal implementation of Hu and the teaching of the present patent application are mutually incompatible, and so the claimed invention in the present patent application is neither identically disclosed or obvious in light of Hu, even in combination with Swanson.
Even if the optimal implementation of Hu and the teachings of the present patent application were not mutually incompatible, which they are, paragraph [0047] of Hu states, that the variation in optical path lengths "can be, for example, about 0.5 mm to about 5 mm (e.g., about 0.5 mm, about 1.0 mm, about 1.5 mm, about 2.0 mm, about 2.5 mm, about 3.0 mm, about 3.5 mm, about 4.0 mm, about 4.5 mm, or about 5.0 mm, including any values and Sub ranges in between)." In contrast, para. [0062] of the present application states that "The fine/tuning delay needs to achieve variation in path length of the order of lOs of mm, e.g. up to 80 mm, although a lower range is still very useful (e.g. 10-20 mm) depending on the application." Therefore, Hu does not provide sufficient variation in the desired optical path length to be suitable for OCT.
Even if Hu did provide sufficient variation in the desired optical path length, which it does not, and even if one were to ignore the issue of optical noise in Hu, which one cannot, the footprint of the invention described in Hu is at least 33% bigger than that of the present patent application when applied to the example given in [0067] of the present patent application. See Hu, at Abstract, claims 2-7, and paras. [0008], [0023], [0029], [0037], and [0087]-[0094]. This is because the relationships between different delay options in each of the interference arms of Hu create two incomplete sets of path lengths. A smaller footprint is important for compact and portable OCT as
this reduces the overall size of the chip, as described in paragraphs [0010] and [0074] of the published application.
In contrast, in claim 1 of the present patentapplication, the length of the Nth "variable" waveguide is independent of the length of any of the "reference" waveguides. The length of the Nth "variable" waveguide in claim 1 of the present patent application is 2NLp. As noted previously, L, is simply referred to as L in the present patent application, however we refer to it as L, here to avoid confusion with the L used in Hu, which is different and should not be conflated with our L. For clarity, Applicant also notes that Claim 1 of the present patent application defines N as an integer (i.e., the first "variable" waveguide can correspond to N=0), while paragraph [0008] of Hu defines n = 1, 2, ... (i.e. the first "variable" waveguide corresponds to n=1).
In the present patent application, the first three "variable" path elements are L, (for N=0), 2L, (for N=1), and 4L, (for N=2). By switching through the first and third "variable" path element, but not the second, this allows for a total delay path of 5L, (see claim 1 and [0067] of the published application).
L + 24(L/2) = L + 23L = 9L. This can be compared to the length ofthe first "variable" path element, L + 20AL = L + L/2 = 3L/2, and the length of the second "variable" path element, L + 22AL = L + 4L/2 = 3L. Combining the first and third "variable" path elements creates a total delay path of 21L/2, which is 7x the length of the first "variable" path element, as opposed to 5x the length of the first "variable" path element in the present patent application.
This means that, for Hu to achieve a total delay path that is 5x the length of the first "variable" path element, the second interference arm must also be utilized. The simplest method would be to set the first "variable" path element in the second interference arm as equalling 5x the length of the first "variable" path element in the first interference arm. This means Hu would require four "variable" path elements to achieve the same total delay path that is achieved with three "variable" path elements in the present patent application, meaning the footprint of Hu is at
least 33% bigger than the footprint of the invention disclosed in the present patent application, when applied to the example given in [0067] of the present patent application.
Applicant notes that 33% is the lower bound for the increase in footprint because the splitter in Hu must also be of finite size. This problem is also not unique to the example given in [0067] of the present patent application. For example, it can be seen from the calculations above that the same issue arises when combining the second and third "variable" path elements to create a total delay path that is 6x the length of the first "variable" path element.
One could re-run the above calculations, applied instead to the second interference arm of Hu. However, the second interference arm comprises a sequence of decreasing "variable" path lengths, whereas the disclosed technology describesa sequence of increasing "variable" path lengths, meaning the two are not comparable.
Even one were to ignore this, which one should not, and were to attempt to replicate the total delay paths from [0067] "in reverse", the footprint still increases by at least 33%. By "in reverse", we mean that we attempt to engineer the second interference arm such that the second "variable" path length is 2x the length of the third "variable" path length and the first "variable" path length is 4x the length of the third "variable" path length. In this case, it is required that AL = L/56 in order for the second "variable" path length to be equal to 2x the length of the third "variable" path length. However, the first "variable" path length will then be 2.25x the length of the third "variable" path length meaning, once again, the minimum number of "variable" path lengths needed to recreate the example given in [0067] of the present patent application is four, provided the first interference arm in Hu is also utilised.
For each additional "variable" path length, an additional optical switch is required (see, for example, claim 5 of Hu). For each additional optical switch, there is an additional electronic control feedback block (see [0051]-[0060], [0070] and figure 3c of the present patent application). This means that the footprint of the control electronics must also increase by at least 33% in the case of Hu and the total OCT system will be materially larger. Therefore, the invention disclosed in Hu has a footprint that is unsuitable for compact and portable OCT. In addition, the the pending claims are neither identically disclosed or obvious in light of Hu, even in combination with Swanson.
Even if one were to ignore the issues associated with having a 33% greater footprint, which one should not, the example given in [0064] of the present patent application states that "the lower rail adds no significant delay to the path length comprised of non-delay path elements". In other
words, the length of the "reference" waveguide, L- 0. Applying this to the second interference arm of Hu for AL > 0 (as required by [0092] of Hu) results in the lengths of all the "variable" waveguides being less than 0. This is unphysical and, combined with the first interference arm's inability to generate a total delay path of 5x or 6x the length of the first "variable" path element, means that the invention disclosed in Hu cannot reproduce the example given in [0064] of the present patent application. Therefore, the pending claims are neither identically disclosed or obvious in light of Hu, even in combination with Swanson.
Even if one were to attempt to reduce the footprint of Hu by only implementing the first interference arm, which one should not, this would prevent path matching for certain values of the target signal path length. As outlined above, using only the first interference arm would prohibit certain total delay paths from being implemented, including those that are 5x and 6x the length of the first "variable" path element.
As mentioned above, if one were to abandon any attempt to implement total delay paths that are 5x or 6x the length of the first "variable" path element, which one should not, Hu states in claim 8 that AL/L is about 0.01 to 0.3. As shown above, AL/L = 0.5 is required to achieve "variable" waveguide lengths equal to L, and 2Lp. Therefore, the range of values given by Hu for AL/L are unsuitable for OCT.
As mentioned above, if one were to use only the second interference arm, which one should not, then it is only possible to avoid unphysical "variable" path lengths if it is configured to generate "variable" path lengths that increase with m. To do this, one must use a negative value of AL. Choosing AL = -L/2 is necessary to ensure the second "variable" path element is twice the length of the first "variable" path element. However, this then generates the same sequence of "variable" path lengths as in the first interference arm, meaning a total delay path that is 5x and 6x the length of the first "variable" path element is once again prohibited.
As mentioned above, AL/L = -0.5 is also outside the range of values given by claim 8 of Hu for AL/L. Therefore, even if attempts to implement total delay paths of 5x or 6x the first "variable" path element were once again abandoned, which they should not be, the range of values given by Hu for AL/L remain unsuitable for OCT.
As noted in [0007] of the present patent application, "A problem with existing OCT apparatus is matching the reference path length to the sample path length.". Therefore, the above demonstrates that only implementing one of the interference arms renders the invention disclosed
in Hu unable to solve this problem, as there are values of the sample path length that cannot be matched, whether or not the range of values given by Hu for AL/L are adhered to. Furthermore, and in addition to the reasons already given, only implementing one of the interference arms of Hu actively makes it unsuitable for OCT. The sample path lengths are specific and unique for each individual and can differ widely (see [0008], [0042] and [0049] of the present patent application), meaning some individuals may be unable to be scanned if not all sample path lengths can be matched.
. In the previous example with three "variable" path lengths, thismeans j/2 = 3, returning AL = L/56, as noted above. As j/2 increases, AL - 0 and so the length of the mth "variable" waveguide, L - 22m-1AL - L for all but the shortest few "variable" waveguides. For example, if j/2 = 5, the "variable" waveguides have lengths 3L/7, 6L/7, 27L/28, 111L/112, and 447L/448, where the lengths of the longest two "variable" waveguides are both >99% of the length of the "reference" waveguide. The shortest "variable" waveguide is always 3L/7, so this caps the longest "variable" waveguide at 2.33x the length of the shortest "variable" waveguide.
Therefore, it is not possible to generate a total delay path that is 5x or 6x the length of the shortest "variable" delay path in any efficient manner. This renders the second interference arm from Hu unsuitable for OCT, in addition to all of the reasons previously given.
There is no evidence that it is possible to generate a total delay path that is 5x or 6x the length of the shortest "variable" delay path even in an inefficient manner. However, if one were to assume that some inefficient configuration does exist, which one should not, it would require additional "variable" waveguides of lengths that are substantially different to one another (i.e. not all > 0.99L). This can only be achieved by sacrificing the requirement that the second shortest
"variable" waveguide is twice the length of the shortest "variable" waveguide, so as to reduce the length of the shortest "variable" waveguide and/or reduce the step size in length between each "variable" waveguide. If one were to do this, it would increase the number of switches and "variable" waveguide/"reference" waveguide pairs, resulting in a longer delay line overall. This would introduce unwanted dispersion, elongate the settling time when changing paths, and induce instability on the chip (see [0009] and [0074] of the present patent application). Therefore, even an inefficient configuration of the second interference arm in Hu, which we do not concede even exists, would be wholly unsuitable for OCT, both PIC-based and in general.
For at least the above reasons, Applicant respectfully submits that there would be no reason to combine the teachings of Swanson with those of Hu, and that independent Claims 1 and 17, as currently amended, are patentable over the cited combination. As the remaining claims depend from or otherwise incorporate the features of a patentable independent claim, Applicant respectfully submits that they are also patentable over the cited art at least by virtue of their dependency from a patentable independent claim, in addition to reciting further patentable distinction.  Furthermore, Applicant does not necessarily agree with the Examiner's characterization of the cited art with respect to the features of these dependent claims.
In view  of the above amendments and remarks, Applicant respectfully requests reconsideration and withdrawal of the rejection of the pending claims under 35 U.S.C. § 103.
No Disclaimers or Disavowals
Although the present communication may include alterations to the application or claims, or characterizations of claim scope or referenced art, Applicant is not conceding in this application that previously pending claims are not patentable over the cited references. Rather, any alterations or characterizations are being made to facilitate expeditious prosecution of this application. Applicant reserves the right to pursue at a later date any previously pending or other broader or narrower claims that capture any subject matter supported by the present disclosure, including subject matter found to be specifically disclaimed herein or by any prior prosecution. Accordingly, reviewers of this or any parent, child or related prosecution history shall not reasonably infer that Applicant has made any disclaimers or disavowals of any subject matter supported by the present application.
Conclusion