The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
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 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.
DETAILED ACTION
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 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1 – 5, 8, 9, 12, 13, and 16 – 19 are rejected under 35 U.S.C. 103 as being unpatentable over Wohlfeil et al (EP 3671297 A) in view of Kono et al (JP 2014-112171), and further in view of Liu et al (CN 115407534 A).
Regarding claims 1, 18, and 19, Wohlfeil discloses (Fig. 1; para. 0042 – 0071) an optical device/module 108 (“a coherent optical transceiver 108” at para. 0042), comprising:
an optical modulator element 118 comprising an optical modulator 110 for performing electro-optic modulation (“electrical drivers that are provided in order to create driver signals for the optical modulator 110” at para. 0042); and
an optical receiver element 108.
Wohlfeil teaches that the optical modulator 110 is configured to individually modulate two orthogonal polarization components (STXh and STXv; Fig. 1; para. 0043), but does not expressly teach (i) a polarization component for combining the polarization components. Wohlfeil does not teach (ii) that the optical modulator element 118 and the optical receiver element 108 can be formed in different materials. However, Kono and Liu provide features (i) and (ii), as detailed below.
As for feature (i), Kono discloses (Fig. 5; para. 0031 – 0034) an optical modulator element including an optical modulator including an electro-optic material (lithium niobate 1) and a polarization element 51 (para. 0056), the polarization element 51 enabling a DP-QPSK type of modulation so that the two orthogonal polarizations components are modulated individually by child/nested Mach-Zehnder interferometers (para. 0032) and subsequently combined by the polarization element 51 (para. 0008).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention that the optical modulator element of Wohlfeil can comprise, in accordance with the teachings of Kono, a polarization element (combiner) in order to support dual-polarization operation as generally considered by Wohlfeil, and enable a DP-QPSK type of modulation, as described by Kono, so that the two orthogonal polarizations components are modulated individually by Mach-Zehnder interferometers and combined by the polarization element 51.
As for feature (ii), the Wohlfeil – Kono combination considers hybrid integration of different materials (lithium niobate 1 for the optical modulator and quartz for passive/non-modulating portions in 13,13’; para. 0024 of Kono), but does not teach that the optical modulator element 118 and the optical receiver element 108 can be formed by hybrid integration of different materials. However, Liu discloses (Fig. 2; para. 0008 – 0032) an optical device, comprising:
an optical modulator element 2 (para. 0010) formed in an electro-optic material (lithium niobate; para. 0010); and
an optical receiver element 5,8 formed in a different material (silicon; para. 0051) and integrated with the optical modulator element 2 in a compact/miniaturized module with hybrid integration (para. 0023, 0024, and 0034).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention that the optical modulator element 118 and the optical receiver element 108 can be formed by hybrid integration of different materials, in accordance with the teachings of Liu, in which case the performance of the optical modulator element 118 and the optical receiver element 108 can be optimized/improved independently from each other.
The Wohlfeil – Kono – Liu combination considers a variety of suitable/workable layouts with different distributions/locations of constituent parts between the region of the electro-optical material and the region of silicon material. In particular, a polarization combiner may be disposed either within the electro-optical material region or within the silicon region, as a matter of suitable/workable designs choice that work equally well. The latter layout (the polarization combiner is disposed within the silicon region of the optical receiver) is illustrated in Figure A below which is produced from Fig. 1 of Wohlfeil by using lithium niobate for the optical modulator 118 and silicon for the optical receiver element 108. Note that:
(a) the optical fibers 144, 146, 148 can be replaced with integrated-optic waveguides (as taught by Wohlfeil (para. 0050) and Kono (Fig. 5)); and
(b) the U-shaped fiber loop in Fig. 1 is used only to facilitate the alignment of the device and should be removed/severed for proper operation of the coherent transceiver which must have, as illustrated in Figure A, a modulated optical output from the optical modulator and an optical input to be received by the optical receiver (a transceiver transmits data and receives data), and additionally have an optical input from a local oscillator (for a coherent transceiver).
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Figure A. A coherent transceiver of the Wohlfeil – Kono – Liu combination.
As seen in Figure A, the Wohlfeil – Kono – Liu combination considers an optical device/module (coherent transceiver), comprising:
an optical modulator element (in lithium niobate) including a first optical waveguide extending to a first end face, a first inter-element waveguide extending to a second end face, and an optical modulator including an electro-optic material (lithium niobate); and
an optical receiver element (in silicon) including a second optical waveguide extending to a third end face, a second inter-element waveguide extending to a fourth end face, an optical receiver, and a polarization element (combiner),
wherein the first inter-element waveguide and the second inter-element waveguide have been connected to each other by being butted against each other (at the interface between the (upper) lithium niobate region of the optical modulator and the (lower) silicon region of the optical receiver.
Further for claim 19, the Wohlfeil – Kono – Liu combination considers that the contemplated coherer transceiver further comprises a processor that executes signal processing for the optical modulator and the optical receiver (e.g., para. 0042 of Wohlfeil).
To sum up the applied prior art, Wohlfeil discloses a coherent transceiver with an optical modulator (modulating light of both polarization components) and an optical receiver. Kono further details that such modulator can comprise a polarization component/combiner (feature (i)), while Liu suggests that the optical modulator and the optical receiver can be formed in different materials (hybrid integration) and their waveguides can be butted at an interface between the different materials (feature (ii)).
As an aside and relevant comment, it is also noted that the coherent transceiver of the Wohlfeil – Kono – Liu combination has essential structural features (a coherent transceiver with a local oscillator and hybrid integration so that the modulator and the receiver are formed in different materials) and a principle of operation (high-speed modulation and coherent reception) that are substantially similar/identical to those of the claimed coherent transceiver, as evident from a direct side-by-side comparison of Figure A with Fig. 1 of the instant application.
Regarding claim 2, the Wohlfeil – Kono – Liu combination considers that the first end face and the third end face can be parallel (vertical), and in particular, coplanar with each other, as illustrated in Figure A provided above for claim 1. The Wohlfeil – Kono – Liu combination renders obvious a variety of other suitable layouts that work well and provide flexibility is arranging the constituent parts of the coherent transceiver and optimizing their locations for a particular application.
Regarding claim 3, the Wohlfeil – Kono – Liu combination considers (see Figure A provided above for claim 1) that the contemplated coherent receiver is butt-coupled with 3 optical fibers (para. 0051 and 0095 of Wohlfeil), for a modulated optical output from the optical modulator, an optical input to be received by the optical receiver, and an optical input from a local oscillator (for a coherent transceiver). In such arrangement, the first optical waveguide extends to the first end face and a local optical fiber (carrying an input light Spos from a local oscillator, as disclosed by Wohlfeil; para. 0044 and 0056) have been connected to each other by being butted against each other (as seen in Figure A), and
an input optical fiber (carrying input light for detection by the optical receiver) and an output optical fiber (for modulated light from the optical modulator), and the second optical waveguide extending to the third end face have been connected to each other by being butted against each other.
It is noted that the input and output fibers can be disposed/fixed within a base 180,182 (Fig. 6; para. 0095 of Wohlfeil), and the base 180,182 is abutted (and glued to) to the first and/or third end face.
Regarding claim 4, the Wohlfeil – Kono – Liu combination considers (see Figure A provided above for claim 1) that a local optical fiber (carrying an input light Spos from a local oscillator, as disclosed by Wohlfeil; para. 0044 and 0056), an input optical fiber (carrying input light for detection by the optical receiver), and an output optical fiber (for modulated light from the optical modulator), and the first optical waveguide extending to the first end face have been connected to each other by being butted against each other (as seen in Figure A). It is noted that the input and output fibers can be disposed/fixed within a base 180,182 (Fig. 6; para. 0095 of Wohlfeil), and the base 180,182 is abutted (and glued to) to the first and/or third end face.
Regarding claim 5, the Wohlfeil – Kono – Liu combination considers (see Figure A provided above for claim 1) that a local optical fiber (carrying an input light Spos from a local oscillator, as disclosed by Wohlfeil; para. 0044 and 0056), an input optical fiber (carrying input light for detection by the optical receiver), and an output optical fiber (for modulated light from the optical modulator), and the second optical waveguide extending to the third end face have been connected to each other by being butted against each other (as seen in Figure A). It is noted that the input and output fibers can be disposed/fixed within a base 180,182 (Fig. 6; para. 0095 of Wohlfeil), and the base 180,182 is abutted (and glued to) to the first and/or third end face.
Regarding claims 8 and 9, the Wohlfeil – Kono – Liu combination considers that the electro-optic material can be a perovskite-type oxide, such as LiNbO3 (lithium niobate; para. 0002, 0030, and 0056 of Kono; para. 0034 and 0050 of Liu).
Regarding claims 12 and 13, the Wohlfeil – Kono – Liu combination intends to improve the stability of the contemplated module with respect to temperature variations and uses a substrate 102 on which the optical modulator element and the optical receiver are mounted (para. 0042, 0050, and 0054 of Wohlfeil). Wohlfeil states that the substrate 102 preferably includes a “temperature-stable” material and lists ceramics or silicon (para. 0042 and 0050) as examples of such materials. Hence, the Wohlfeil – Kono – Liu combination renders obvious that the substrate includes a (silicon) material having an expansion coefficient that is approximately equal to an expansion coefficient of a Si substrate of the optical receiver element.
Regarding claims 16 and 17, the Wohlfeil – Kono – Liu combination considers that the first inter-element waveguide and the second inter-element waveguide are formed in different materials (lithium niobate and silicon, respectively) and, hence, have different mode sizes. The Wohlfeil – Kono – Liu combination considers that at least one of the first inter-element waveguide and the second inter-element waveguide has a spot size converter that optically couples the first inter-element waveguide and the second inter-element waveguide to each other. In fact, Wohlfeil expressly teaches the use of a tapered spot-size converter 142 that has a width or thickness varying along tis length and optically couples waveguides formed in different materials in order to match their mode sizes and thereby reduce optical coupling loss at the interface (“a further portion 142b of the waveguide structure 142, which serves as a spot size converter (SSC). In the embodiment shown in Fig. 3, the waveguide structure portion 142b includes three integrated waveguides 144a, 146a, 148a which realize a spot size conversion functionality, i.e. which transform the mode field of the waveguide structure 118 of the PIC 104 at the respective end faces (or ports) into the mode field of the optical fibers 144, 146, 148. This helps to reduce the attenuation at the interface between the PIC 104 and the optical coupling device 106. As apparent from Fig. 3, at least a front portion of the integrated waveguides 144a, 146a, 148a, e.g. the front portion neighboring the interface to part 106b comprising the waveguide structure portion 142b, may be a tapered portion realizing the spot size conversion functionality” at para. 0078 of Wohlfeil, emphasis added)
Claims 6 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Wohlfeil in view of Kono, in view of Liu, and further in view of Nagarajan et (US 10,754,091 B1).
Regarding claim 6, the Wohlfeil – Kono – Liu combination considers the optical modulator element includes (see Figure A provided above for claim 1):
an optical phase modulator (in each arm of each child/nested Mach-Zehnder interferometer modulator, as identified in Figure A) that performs phase modulation of signal light (as need for proper operation of child/nested Mach-Zehnder interferometer modulator); and
an optical phase adjuster (in an arm of a main/parent Mach-Zehnder modulator, as identified in Figure A) that adjusts a phase of the signal light that has been subjected to the phase modulation.
While Wohlfeil does not expressly identified such well known elements, Nagarajan discloses (Fig. 1; 2:39 – 65; 7:51 – 9:50) an optical coherent transceiver that has essential structural features similar to those in Wohlfeil and comprises:
an optical modulator (“Coherent Transmitter Block”) element; and
an optical receiver element (“Coherent Receiver Block”) comprising an optical receiver 3200,3300;
a polarization element/combiner 2200; and
an inter-element waveguide (from a power splitter 1001 and the input of the input of the DP-QPSK Mach-Zehnder modulator,
wherein the optical modulator element includes:
an optical phase modulator (in each arm of each child/nested Mach-Zehnder interferometer modulator; 3:40 – 50) that performs phase modulation of signal light (as need for proper operation of child/nested Mach-Zehnder interferometer modulator); and
an optical phase adjuster 2401,2402 (in an arm of a main/parent Mach-Zehnder modulator; 13:19 – 41) that adjusts a phase of the signal light that has been subjected to the phase modulation.
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention that the optical modulator of the Wohlfeil – Kono – Liu combination has an optical phase modulator and an optical phase adjuster performing their intended functions as taught by Wohlfeil and expressly identified/named by Nagarajan.
Regarding claim 7, the Wohlfeil – Kono – Liu – Nagarajan combination considers that the optical modulator element has an optical phase modulator that performs (high-speed) phase modulation of signal light. The optical phase adjuster (90-degree phase adjusters 2401,2402 in Fig. 1 of Nagarajan) can be implemented as electro-optic phase adjusters/shifters (25:50 – 56) or thermo-optic adjusters/shifters (heaters) in silicon, as another well-known type cited by Nagarajan (Fig. 10; 21:46 – 48; 15:30 – 32). Such thermo-optic adjusters/shifters (heaters) in silicon may be disposed with the silicon region of the optical receiver. In such arrangement, the optical receiver element has an optical phase adjuster (90-degree phase adjuster) that receives the signal light subjected to the (high-speed) phase modulation (in the lithium niobate region) by the optical phase modulator through the first inter-element waveguide and the second inter-element waveguide and that adjusts a phase of the received signal light subjected to the phase modulation.
Claims 10 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Wohlfeil in view of Kono, in view of Liu, and further in view of Heidelberger et (US 2023/0400652 A1).
Regarding claims 10 and 11, the Wohlfeil – Kono – Liu combination considers, by way of example but not limitation, such electro-optic material as lithium niobate (considered by Kono and Liu), even though a wide variety of other electro-optic materials are well known in the art. In this regard, Heidelberger discloses (Fig. 1; para. 0039 – 0041 and 0062) an optical waveguide device with hybrid integration with a silicon-based waveguide 110 that is butted against a waveguide 130 in an electro-optic material that is “alloys of gallium arsenide in the III-V region” and can comprise InGaAsP or AlGaAsP (para. 0062).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention that the electro-optic material in the modulator of the Wohlfeil – Kono – Liu combination can alternatively or additionally comprise InGaAsP or AlGaAsP, as a suitable/workable material choice that is amenable to CMOS technology (para. 0004) and may facilitate manufacturing (compared to lithium niobate).
It is also noted that it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. See In re Leshin, 125 USPQ 416.
Claims 14 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Wohlfeil in view of Kono, in view of Liu, and further in view of Sugiyama (US 2019/0372664 A1).
Regarding claim 14, the Wohlfeil – Kono – Liu combination does not limit the angle that the first inter-element waveguide and the second inter-element waveguide define with respect to a line normal to the second end face and the fourth end face (i.e., the interface between the lithium-niobate region and the silicon region), but does not expressly illustrate embodiments with a slanted angle (different from 90 degrees). However, Sugiyama discloses (Figs. 1 – 3 and 5 – 7; para. 0036 – 0076) an optical transceiver that has waveguides 109/119 extending to an input/output interface between different materials/media. Sugiyama expressly illustrates embodiments (e.g., Figs. 5 – 7) wherein waveguides 119 make an oblique angle with the interface between different materials/media. It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention that the first inter-element waveguide and the second inter-element waveguide of the Wohlfeil – Kono – Liu combination can be oriented to form an oblique (different from 90 degrees) angle to the second end face and the fourth end face (the interface separating different materials, i.e., lithium niobate and silicon). The benefit of such oblique angle is that the (undesirable) impact of back-reflections at the interface is reduced/mitigated (para. 0054 and 0065 of Sugiyama).
Regarding claim 15, selection of a proper range of the oblique angle would be well within ordinary skill in the art of optical waveguide devices (which is noted as being high).
It is also noted that (i) the range limits depend on a particular application (a particular selection of materials and their refractive indices, an acceptable level of reflection, etc); that (ii) the instant application does not provide any criticality for the exact values of the recited range limits; that (iii) it has been held that discovering the optimum or workable ranges of prior art involves only routine skill in the art (In re Aller, 105 USPQ 233); and that (iv) it has been held that "A recognition in the prior art that a property is affected by the variable is sufficient to find the variable result-effective." In re Applied Materials', Inc., 692 F.3d 1289, 1297 (Fed. Cir. 2012). It is well settled that it would have been obvious for an artisan with ordinary skill to develop workable or even optimum ranges for result-effective parameters. In re Boesch, 617 F.2d 272, 276 (CCPA 1980); see also In re Woodruff, 919 F.2d 1575, 1577-78 (Fed. Cir. 1990). The Wohlfeil – Kono – Liu – Sugiyama combination considers the angle of inclination as a result-effective parameters (affects back-reflection).
Claims 1, 18, and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Nagarajan in view of Liu.
Regarding claims 1, 18, and 19, Nagarajan discloses (Fig. 1; 2:39 – 65; 7:51 – 9:50) an optical device/module (coherent transceiver) comprising:
an optical modulator (“Coherent Transmitter Block”) element; and
an optical receiver element (“Coherent Receiver Block”) comprising an optical receiver 3200,3300;
a polarization element/combiner 2200; and
an inter-element waveguide (from a power splitter 1001 and the input of the input of the DP-QPSK Mach-Zehnder modulator.
While Nagarajan does not tech that the optical device/module can be formed by hybrid integration so that the optical modulator and the optical receiver element are formed in different materials, Liu discloses (Fig. 2; para. 0008 – 0032) an optical device, comprising:
an optical modulator element 2 (para. 0010) formed in an electro-optic material (lithium niobate; para. 0010); and
an optical receiver element 5,8 formed in a different material (silicon; para. 0051) and integrated with the optical modulator element 2 in a compact/miniaturized module with hybrid integration (para. 0023, 0024, and 0034).
It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention that the optical modulator element and the optical receiver element in Nagarajan can be formed by hybrid integration of different materials, in accordance with the teachings of Liu, in which case the performance of the optical modulator element and the optical receiver element can be optimized/improved independently from each other.
The Nagarajan – Liu combination considers a variety of suitable/workable layouts with different distributions/locations of constituent parts between the region of the electro-optical material and the region of silicon material. In particular, a polarization combiner may be disposed either within the electro-optical material region or within the silicon region, as a matter of suitable/workable designs choice that work equally well. The latter layout (the polarization combiner is disposed within the silicon region of the optical receiver) is similar/identical to that
illustrated in Figure A provided above for the rejections based on Wohlfeil and meets all of the recited limitations, as detailed therein.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
CN 115542458 A
US 2014/0023313 A1
US 2003/0128905 A1
US 2021/0215878 A1
US 2020/0322057 A1
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/ROBERT TAVLYKAEV/Primary Examiner, Art Unit 2896