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 .
Claim Objections
Claim 15 objected to because of the following informalities: grammatically awkward claim construction. Claim 15 recites the phrase “…Wherein the driver comprises two signal outputs via each of which the driver provides an alternating…” This phrasing is awkward and makes the intended meaning/scope difficult (though not impossible) to ascertain. The examiner recommends revising to “…wherein the driver comprises two signal outputs, each driver providing an alternating…” or something similar. 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.
Claims 7, 12 and 13 is/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 7:
Claim 7 recites that “the outputs of the driver are arranged side by side in the order of first ground output, first signal output, second signal output, second ground output.” This recitation assumes the existence of a first ground output, a first signal output, a second signal output, and a second ground output.
Claim 6, from which claim 7 depends, recites these outputs in the alternative (“…and/or…”), and thus embodiments in which only one of the further outputs is present are valid readings of the claim. As such, it is unclear whether claim 7 requires all four outputs and if it is limited to the subset of claim 6 embodiments in which all four are present.
Appropriate correction is required. Amending claim 6 require all further outputs or modifying claim 7 to accept a subset of the outputs in correspondence with claim 6 would most easily remedy this indefiniteness. The examiner interprets the claim as 4 outputs are required.
Regarding claim 12:
Claim 12 recites the claim elements “…the input waveguide…” and “…the input coupler…”. There is insufficient antecedent basis for these elements, they are introduced in claim 11 and not claim 1. For the purposes of examination, the examiner understands the input waveguide and input couplers to be those as claimed in claim 11, but appropriate correction is required to rectify the issue of indefiniteness in claim 12.
Claim 13 is dependent on claim 12 and inherits its indefiniteness.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 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) 1-7, and 11-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Jacques (US 20240248331 A1) in view of Kharel (US 20210311336 A1), and further in view of Ozaki (US 11467467 B2).
Regarding claim 1:
Jacques discloses a modulator arrangement (Title), comprising:
An optical thin film lithium niobate Mach-Zehnder modulator (paragraph 5, “…modulator structures…such as thin-film lithium niobate [TFLN].”) with a first and second waveguide arm (Paragraph 30, Figure 3, CW light goes into a waveguide with a first and second arm) arranged on a substrate (Claim 15, “The linear electro-optic modulator of claim 14, comprising a substrate of silicon or quartz.”), wherein the first and the second waveguide arm each include an area formed of lithium niobate (Paragraph 38, “Each light beam travels through a thin-film lithium niobate arm”);
an electrode arrangement for generating an electric field which at least sectionally acts on the first and second waveguide arms (paragraphs 40-42, the S and S’ electrodes, together with ground traces, generate an RD electric field, where “Arm 2 of the MZM… sees… a 100% increase in the 2nd half 420, due to the ‘push-pull’ effects of the combined electrodes…” confirming that the electrode arrangement produces an E-field which acts on both arms),
wherein the electrode arrangement comprises a first and second signal line and a first and a second ground line (Figure 4, The GSSG modulator 400 comprises two ground traces G and a first and second signal trace S and S’, with gaps 401, 402, and 403 defines as “between G and S traces and between the S S’ traces),
And a differential driver for providing a voltage for the Mach-Zehnder modulator (paragraph 38, “…can be directly driven by conventional differential-output driver architectures of the type GSSG or GSGSG, which are the differential schemes employed.”), wherein a signal output of the driver is connected to the first signal line and a ground output is connected to the second ground line (paragraph 67, “if biasing the DAC/driver through its outputs, both MZM termination schemes of FIG. 11 allow for a reduction in the RF loss between the driver output and TFLN”).
Insofar as the claim requires “a ground output is connected to the second ground line,” Jacques discloses a GSS’G-type differential output driver and grounds common to the driver and MZM via its termination schemes. But it does not expressly depict a driver ground output bonded to the second ground line. It would have been obvious to connect the driver’s ground output to the second ground line, because a differential output driver presenting a GSSG footprint necessarily has ground terminals, and connecting those terminals to the mating ground traces of the GSSG modulator is the predictable and ordinary means of completing the RF return path.
Jacques does not expressly disclose wherein the first signal line at least sectionally extends above the first waveguide arm so that the first signal line – as seen in a direction perpendicular to the substrate – is aligned with the first waveguide arm, wherein the second ground line at least sectionally extend above the second waveguide arm so that the second ground line – as seen in a direction perpendicular to the substrate – is aligned with the second waveguide arm;
Ozaki, also in the field of differential-drive Mach-Zehnder optical modulators having a GSSG electrode structure (Abstract), discloses connecting a ground output of the differential driver to a ground line of the modulator:
Figure 1, high frequency line 14 in a GSSG configuration comprising signal lines 140, 141, and ground lines 142, 143 disposed on respective side of the signal lines, driven by a differential driver IC 2 having signal pads 20, 21 and ground pads 22-24 (Figure 2), wherein the driver’s ground pads are connected to the modulator’s ground lines.
Kharel, in the same field of thin-film lithium niobate MZMs, discloses a z cut modulator (Figs 5A-5C, device 51) in which the modulating electrodes are positioned directly above and vertically aligned with the optical waveguide arms. Specifically, Kharel discloses:
A first signal line extending above and aligned with the first waveguide arm, as seen perpendicular to the substrate (electrode 67 may be positioned above and parallel to the first waveguide 61; the first and second optical waveguides 11 and 12 run directly underneath the first and second signal electrodes 117 and 119, respectively); and
A second ground line extending above and aligned with the second waveguide arm, as seen perpendicular to the substrate (ground electrode 68 is disposed above the second waveguide 62, and parallel therewith).
Before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to modify the invention described in the invention of Jacques under the teachings of Kharel and Ozaki to include a first signal line above the first waveguide arm and a second ground line above and aligned with the second waveguide arm, and also to ensure that the ground output of the differential driver is connected to the second ground line as taught by Ozaki. This may be accomplished using components (signal lines), materials (Cu, Al, metals in general), and routine discretion in the placement and formation of the device known to a skilled artisan. Predictably, this would result in a device where the modulation efficiency is increased, while the ground connection modification would result in a low inductance RF return path that suppresses reflection and preserve signal integrity.
Regarding claim 2:
Jacques in view of Ozaki and Kharel discloses modulator arrangement according to claim 1, wherein the area formed of lithium niobate includes at least one lithium niobate layer (“thin-film lithium niobate”)
Jacques does not expressly disclose that the LiNbO3 layer is in a z-cut orientation.
Kharel discloses a thin-film LiNbO3 MZM modulator (Abstract, Paragraph 34), wherein:
“the electro-optic device 51, e.g. modulator, may comprise a Z-cut electro-optic material for the first and second waveguides 61 and 62,” (paragraph 50).
A z-cut orientation allows for a Pockels coefficient which is oriented orthogonal to the substrate, such that the over-the-arm electrode placement adopted in the invention of claim 1 orients the electric field and maximizes field/optical mode overlap.
Before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to modify the invention described in the rejection of claim 1 above under the teachings of Kharel to ensure that the Lithium Niobate layers are in a z-cut orientation. This may be accomplished during the formation of the waveguiding layers using methods known to a skilled artisan, and would predictably result in a device where in the electric field and optical mode overlap is such that the phase-shift efficacy is maximized and drive-voltage is reduced. This efficiency is a prime directive in the art and the z-cut geometry that supports it would be an obvious design choice to a skill artisan.
Regarding claim 3:
Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 1.
Wherein the second signal line – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – at least sectionally extends between the first signal line and the second ground line.
Jacques discloses a GSS’G electrode arrangement (i.e Figure 3, 4) in which the traces are arranged, in order, as first ground (G), first signal (S), second signal (S’), and second ground (G) with gaps 401, 402, 403 defined “between the G and S traces and between the SS’ traces”. In this ordering, the second signal line S’ is positioned between the first signal line S and the second ground line G, as viewed in a direction perpendicular to the waveguide arms and parallel to the substrate.
Regarding claim 4:
Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 1.
Wherein the first ground line – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – at least sectionally extends on a side of the first signal line facing away from the second signal line.
Figure 4, first ground line G at least sectionally extends on a side of the first signal line S, which is facing away from the second signal line S’.
Regarding claim 5:
Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 1.
Wherein the signal and ground lines – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – are arranged side by side in the order of first ground line, first signal line, second signal line, and second ground line.
Figure 3,4; the first ground (G, bottom), first signal (S), second signal (S’), and second ground (G, top) are arranged side by side in the order as claimed.
Regarding claim 6:
Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 1.
wherein the driver comprises a further signal output which is connected to the second signal line.
Paragraph 38, the MZM is directly “driven by conventional differential-output driver architectures of the type GS’SG or GS’GSG.” Because a differential driver of the GS’SG type drive a signal onto both signal lines, the driver necessarily comprises a first signal output connected to the first signal line (as in the rejection of claim 1), and a further (second) signal output connected to the second signal line.
The claim does not require that “the driver comprises a further ground output which is connected to the first ground line,” and thus the limitation is unaddressed without admission of a teaching or lack thereof.
Regarding claim 7:
Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 6.
Jacques further discloses the differential driver as being of the type GS’SG, i.e. a driver whose outputs are arranged in a ground-signal-signal-ground footprint, but it does not expressly depict the side-by-side ordering of the driver output pads.
Ozaki discloses a physical arrangement of differential driver output pads (Figure 1), wherein:
signal pad 20 connects to signal line 140, signal pad 21 to line 141, ground pad 22 to ground line 142, and ground pad 23 to ground line 143.
This teaches a GSSG signal line setup with a corresponding side-by-side output pad arrangement as claimed, wherein the outputs of the driver are arranged side by side in the order of first ground output, first signal output, second signal output, and second ground output.
Before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to modify the invention described in the rejection of claim 6 above under the teachings of Ozaki to ensure that the output pad arrangement matches the inputs/signal and ground line arrangement – that is, to mirror the GSS’G order of the modulators transmission lines established in claim 5 – as taught by Ozaki. This may be accomplished using existing components and placement techniques requiring only routine design oversight known to a skilled artisan, and would predictably result in a device where outputs connect directly to corresponding without cross adjacent connections, minimizing wire inductance and impedance discontinuities to improve signal quality.
Regarding claim 11:
Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 1.
Wherein the Mach-Zehnder modulator comprises an input waveguide connected to an input coupler (As shown in Figure 3, and further explained in paragraph 38, “Carrier wave light enters the modulator at an optical input, passes through an optical splitter coupled to the optical input to produce two light beams;” the input is an input waveguide, the splitter is a coupler).
Regarding claim 12:
-Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 1.
Wherein the input waveguide comprises a first portion (Figure 5, the segment of the optical in that comes after the U-bend and which terminates at the optical splitter) connected to the input coupler (the optical splitter after “RF Input”) and a second portion (the portion of “Optical in” up to the U-bend, upstream of the first portion) via which light can be coupled into the input waveguide, wherein the input waveguide has a curvature between the first and second portion (the U-bend).
Regarding claim 13:
- Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 12.
Wherein the Mach-Zehnder modulator comprises at least one output coupler connected to the two waveguide arms (Figure 5, the meeting of waveguide arms just before “optical out”), wherein the second portion of the input waveguide at least partly is located on a side of the output coupler facing away from the waveguide arms.
As shown in Figure 5, the “second portion” is the portion of “Optical In” and the subsequent waveguide upstream of the U-bend (i.e. the bottom of the figure). There are a multitude of means by which this second portion is at least partly on a side of the output coupler (“Optical out”) facing away from the waveguide arms:
The right-most part of the second portion is further to the right than the output coupler along an axis parallel to the second portion (call this the x-axis). There is also a significant portion on the left side of the coupling region (where arms meet) – if ‘facing away’ is with respect to either the direction upstream or downstream of the outcoupling region, then the second portion meets the limitation either way.
The optical-in portion is itself on the opposite side of the outcoupling region. It is necessarily ‘facing away’ as a result.
Regarding claim 14:
-Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 1.
Wherein the driver is configured to apply oppositely directed signals to the first and second signal line.
Jacques is explicitly directed to oppositely directed differential drivers (Paragraphs 3, 41 indicate that the S+ and S- electrodes exert a ‘push-pull’ effects due to their complementary and opposite design, meaning that the first and second signal lines have oppositely directed signals).
Regarding claim 15:
-Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 1.
Wherein the driver comprises two signal outputs via each of which the driver provides an alternating voltage, wherein the alternating voltages provided have opposite polarity.
Jacques discloses complementary components of a differential signal pair in the differential driver, each an alternating (RF) voltage of opposite polarity, to the two signal lines (push-pull S and S’ electrodes, paragraph 40; paragraph 38 describe the modulator as being driven by a differential-output driver of the GSS’G type, which provides two complementary signal outputs). A skilled artisan recognizes this as being alternating voltages of opposite polarity.
Regarding claim 16:
-Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 2.
Wherein the second signal line – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – at least sectionally extends between the first signal line and the second ground line
Jacques discloses a GSS’G electrode arrangement (i.e Figure 3, 4) in which the traces are arranged, in order, as first ground (G), first signal (S), second signal (S’), and second ground (G) with gaps 401, 402, 403 defined “between the G and S traces and between the SS’ traces”. In this ordering, the second signal line S’ is positioned between the first signal line S and the second ground line G, as viewed in a direction perpendicular to the waveguide arms and parallel to the substrate.
Regarding claim 17:
-Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 2.
Wherein the first ground line – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – at least sectionally extends on a side of the first signal line facing away from the second signal line.
Figure 4, first ground line G at least sectionally extends on a side of the first signal line S, which is facing away from the second signal line S’.
Regarding claim 18:
-Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 3.
Wherein the first ground line – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – at least sectionally extends on a side of the first signal line facing away from the second signal line.
Figure 4, first ground line G at least sectionally extends on a side of the first signal line S, which is facing away from the second signal line S’.
Regarding claim 19:
-Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 2.
Wherein the signal and ground lines – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – are arranged side by side in the order of first ground line, first signal line, second signal line, and second ground line.
Figure 3,4; the first ground (G, bottom), first signal (S), second signal (S’), and second ground (G, top) are arranged side by side in the order as claimed.
Regarding claim 20:
-Jacques in view of Ozaki and Kharel discloses modulator arrangement of claim 3.
Wherein the signal and ground lines – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – are arranged side by side in the order of first ground line, first signal line, second signal line, and second ground line.
Figure 3,4; the first ground (G, bottom), first signal (S), second signal (S’), and second ground (G, top) are arranged side by side in the order as claimed.
Claim(s) 8-10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Jacques (US 20240248331 A1) in view of Kharel (US 20210311336 A1), and further in view of Ozaki (US 11467467 B2).
Regarding claim 8:
Kharel discloses a modulator arrangement (Abstract), comprising:
An optical thin film lithium niobate Mach-Zehnder modulator with a first and a second waveguide arm arranged on a substrate, wherein the first and the second waveguide arm each comprises an area formed of lithium niobate,
Figure 1, Paragraph 34: the first and second waveguides 11 and 12 and the second optical coupler 13 are comprised of electro-optical waveguide material, “preferably thin-film electro-optical waveguide material, and more preferably thin-film lithium niobate waveguide material, but other types of waveguides...”
wherein the area formed of lithium niobate comprises at least one lithium niobate layer in an x-cut orientation;
Paragraph 53, Figure 7A: modulator 101 is for x-cut electro-optic first and second optical waveguides 11 and 12
An electrode arrangement for generating an electric field which at least sectionally acts on the first and second waveguide arms, wherein the electrode arrangement comprises a first and a second signal line and a first and a second ground line,
Figure 7A, depicts a ground line G and signal lines S+/S-, both are electrodes and act on the [first (11) and second (12)] waveguide arms.
wherein the first waveguide arm (Figure 7A, waveguide arm 11) extends between the first ground line and the first signal line (waveguide 11 is between G and S+), and wherein the second waveguide extends between the second ground line and the second signal line (waveguide 12 is between the second G and S-);
And a differential driver (paragraph 54, “…dual [differential] drive…”) for generating a voltage for the Mach-Zehnder modulator (the first waveguide passes between the second ground electrode 118 and the first signal electrode 117), with
A first signal output which is connected to the first signal line (Figure 7A, driver output driving S+ 117).
A second signal output which is connected to the second signal line (Figure 7A, driver output driving S- 119).
Kharel does not expressly disclose that the driver comprises a first ground output connected to the first ground line and a second ground output connected to the second ground line. Kharel depicts the driving source (external controller 30) schematically and does not show driver ground outputs bonded to the modulator ground lines.
Ozaki teaches a differential diver (Figure 1), with:
A first ground output which is connected to a first ground line (differential driver IC 2 has ground pad 22 connected to the ground line 142, making a first ground output connected to a first ground line), and
A second ground output which is connected to a second ground line (second ground pad 23 is connected to ground second ground line 143).
Jacques, in the same field of thin-film lithium niobate Mach-Zehnder modulators, discloses driving such a modulator directly with a conventional differential-output driver architecture, expressly including the GS’GSG type and the GS’SG type (this provides prior art support for various terminal arrangements).
Before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to modify the invention described in the invention of Kharel under the teachings of Ozaki and Jacques, to include ground line outputs for the first and second ground lines. This could be accomplished using ground pads connected to the ground lines as taught in Ozaki, and a number of other solutions a skilled artisan would find obvious (Common ground plane via flip chip, ground vias) for known driver architectures (as taught in Jacques). Predictably, this would provide control over the impedance to the driver, minimizing the impedance discontinuity at the driver-modulator interface and suppressing reflected waves that would otherwise degrade the signal.
Regarding claim 9:
Kharel in view of Ozaki and Jacques discloses the modulator arrangement according to claim 8, wherein:
the signal and ground lines – as seen in a direction perpendicular to the waveguide arms and parallel to the substrate – are arranged side by side in the order of first ground line, first signal line, second ground line, and second signal line.
Figures 7A/7B depict the lines in GS+GS- order, which corresponds exactly to the claim.
Regarding claim 10:
Kharel in view of Ozaki and Jacques discloses the modulator arrangement according to claim 9, wherein:
Kharel depicts the dual-drive configuration lines as claimed, but does not expressly show the physical side-by-side ordering of the driver’s output pads.
Ozaki discloses a physical arrangement of differential driver output pads (Figure 1), wherein:
signal pad 20 connects to signal line 140, signal pad 21 to line 141, ground pad 22 to ground line 142, and ground pad 23 to ground line 143.
This teaches a GSSG signal line setup with a corresponding side-by-side output pad arrangement as claimed, wherein the outputs of the driver are arranged side by side in the order of first ground output, first signal output, second signal output, and second ground output.
Before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to modify the invention described in the rejection of claim 9 above under the teachings of Ozaki to ensure that the output pad arrangement matches the inputs/signal and ground line arrangement – that is, to mirror the GSS’G order of the modulators transmission lines as taught by Ozaki. This may be accomplished using existing components and placement techniques requiring only routine design oversight known to a skilled artisan, and would predictably result in a device where outputs connect directly to corresponding without cross adjacent connections, minimizing wire inductance and impedance discontinuities to improve signal quality.
Conclusion
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/PREET B PATEL/Examiner, Art Unit 2874
/THOMAS A HOLLWEG/Supervisory Patent Examiner, Art Unit 2874
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