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 § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1, 4, 6, and 9 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Kawachi et al (US 5,044,715).
Regarding claim 1, Kawachi discloses (Figs. 24A – 24D; 20:33 – 23:43) an optical waveguide device (Mach-Zehnder interferometer; 20:53 – 56) comprising an optical waveguide 82,83,84 formed on a substrate 40, wherein a directional coupler (at least one of 85 and 86; “The optical waveguides 82, 83 and 84 are placed side by side in close proximity at two positions on the substrate, thus forming directional couplers 85 and 86” at 20:45 – 48) is disposed in a part of the optical waveguide 82,83,84, the directional coupler 85 includes one center waveguide 83 and two side waveguides 82,84 disposed to interpose the center waveguide 83 between the side waveguides 82,84 (as seen in Figs. 24A – 24D), the side waveguides 82,84 are disposed to come close to the center waveguide 83 (at section B-B’, as seen in Figs 24A and 24C) from a position where the side waveguides 82,84 are separated from the center waveguide 83 (e.g., at section A-A’, as seen in Figs. 24A and 24B; 20:63 – 21:13) and then to be separated again (at section C-C’, as seen in Figs. 24A and 24D) from the center waveguide 83 in a traveling direction of a light wave (horizontal direction in Fig. 24A), and the center waveguide 83 and the side waveguides 82,84 are not in contact with each other (as seen in Figs. 24A – 24D).
Regarding claim 4, Kawachi teaches (Figs. 24A and 25) input light Pin is launched into the left side of the center waveguide 83 and that the directional coupler 85,86 (its part 85) functions as a branching waveguide that introduces a light wave from one (left) side of the center waveguide 83 and that derives the light wave branching from the two side waveguides 82,84 positioned on the other (right) side of the center waveguide 83 (after the directional coupler 85). At least a portion of the input light Pin launched into the left side of the center waveguide 83 must be split off into the side waveguides 82,84 for the Mach-Zehnder type optical waveguide 82,83,84 to operate as an interferometer (using interference of two or more light waves).
Regarding claim 6, Kawachi teaches (Fig. 24A) that the directional coupler 85,86 (its part 86) functions as a combining waveguide that introduces two light waves into each side waveguide 82,84 from the one side (between 85 and 86) of the two side waveguides 82,84 and that derives a light wave Psub into which the two light waves are combined from the center waveguide positioned on the other side (to the right from 86) of the side waveguides 82,84. The intensity and phase of the light wave Psub is determined by the amplitudes and phases of the light waves of the side waveguides 82,84 as they enter the directional coupler part 86.
Regarding claim 9, Kawachi teaches (Figs. 24A – 24D; 20:33 – 23:43) that the optical waveguide 82,83,84 includes a Mach-Zehnder type optical waveguide (“The 3-waveguide type Mach-Zehnder interferometer circuit is constructed by combining linear patterns and arc patterns” at 20:53 – 56), and the directional coupler 85,86 is incorporated in at least one of a branching part or a Y-junction of the Mach-Zehnder type optical waveguide: if light propagates left to right in Fig. 24A, the directional coupler 85 functions as a branching part of the Mach-Zehnder type optical waveguide 82,83,84.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1 and 9 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by “An Electro-Optic 3x3 Switch Based On Integrated Mach-Zehnder Interferometer” by Rahman et al, Proceedings of the 8th WSEAS International Conference on APPLIED ELECTROMAGNETICS, WIRELESS and OPTICAL COMMUNICATIONS, vol. 2769, paper 1790, 2010 (hereinafter Rahman).
Regarding claim 1, Rahman describes (Figs. 2 and 4; Abstract; Sections 1 and 2) an optical waveguide device (Mach-Zehnder interferometer) comprising an optical waveguide formed on a (lithium niobate) substrate, wherein a pair of 3x3 directional couplers is disposed in a part of the optical waveguide, the directional couplers each include one center waveguide and two side waveguides disposed to interpose the center waveguide between the side waveguides (as seen in Figs. 2 and 4), the side waveguides are disposed to come close to the center waveguide (within the left directional coupler in Fig. 1, at a ~ 5 mm distance from the input interface) from a (input) position where the side waveguides are separated from the center waveguide and then to be separated again (in the parallel interferometer arms) from the center waveguide in a traveling direction of a light wave (horizontal direction in Fig. 1), and the center waveguide and the side waveguides are not in contact with each other (as seen in Fig. 1).
Regarding claim 9, Rahman describes (Fig. 4) that the optical waveguide includes a Mach-Zehnder type optical waveguide (Abstract), and the directional coupler is incorporated in at least one of a branching part or a Y-junction of the Mach-Zehnder type optical waveguide: light propagates left to right in Fig. 4, the (left) directional coupler functions as a branching part of the Mach-Zehnder type optical waveguide.
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 2, 3, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Kawachi in view of Rahman.
Regarding claim 2, while Kawachi does not illustrate a mode size of a light wave propagating through the optical waveguides, Fig. 4 in Rahman illustrates a well-known fact that two or more optical waveguides may be optically coupled and exchange optical energy among them if the optical waveguides are in close proximity of one another, with an inter-waveguide distance not greater than a mode size (determined by its evanescent tail) of a light wave propagating through an optical waveguide. Optical coupling is suppressed at larger distances. Hence, a combination Kawachi and Rahman renders obvious that a distance between the center waveguide and the side waveguides before coming close to the center waveguide and a distance between the center waveguide and the side waveguides after being separated from the center waveguide are set to be twice or more of a mode diameter of a light wave propagating through the optical waveguide. It is also noted that 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. It is also noted that a particular (optimum) distance depends on an intended coupler length. Shorter coupler lengths necessitate shorter inter-waveguide distances.
Regarding claim 3, the Kawachi – Rahman combination considers that an intensity of optical confinement of the optical waveguide in any of the center waveguide or the side waveguides is weaker in a state where the center waveguide and the side waveguides are close to each other than in a state where the center waveguide and the side waveguides are separated from each other: indeed, all 3 waveguides are in close proximity within the input and output directional couplers so that the evanescent tails of the modes of the 3 waveguides penetrate adjacent waveguides which corresponds to looser light confinement, the latter being required for proper operation of the directional couplers.
Regarding claim 10, the Kawachi – Rahman combination considers an optical modulation device (electro-optic switch/modulator, according to Rahman) comprising:
the contemplated optical waveguide device (Mach-Zehnder interferometer with 3x3 directional couplers);
a case accommodating the optical waveguide device (mentioned by Kawachi at 20:16 – 18); and
an optical fiber through which a light wave is input into the optical waveguide or output from the optical waveguide (as suggested by Kawachi: “The silica-based single-mode waveguides are well connected to single-mode optical fibers, providing practical guided-wave optical branching components” at 11:64 - 66).
Claims 5 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Kawachi in view of Rahman, in view of “Optical Low Coherence Reflectometer Using [3x3] Fiber Coupler” by Takada et al, IEEE PHOTONICS TECHNOLOGY LETERS, vol. 6, No. 8, pp. 1014 – 1016, 1994 (hereinafter Takada), and further in view of Kondou (US 2015/0205181 A1).
Regarding claim 5, the Kawachi – Rahman combination considers the most general case of 3-beam interference when light waves propagating in all 3 branches of the Mach-Zehnder interferometer propagate and interfere in the output directional coupler (as illustrated in Fig. 4 of Rahman). The Kawachi – Rahman combination does not illustrate a particular case of 2-beam interference when light waves propagating in only in the side waveguides of the Mach-Zehnder interferometer propagate and interfere in the output directional coupler, while a light wave in the center waveguide does not participate in interference. However, Takada describes (Figs. 1 and 2a; Abstract; Section II) a folded Mach-Zehnder interferometer wherein a 3x3 coupler is used bi-directionally as both an input splitter (going from the source to the sample WUT and the mirror) and an output combiner (from the sample WUT and the mirror to the balanced photodetector). Takada explicitly illustrates a particular case of 2-beam interference when light waves propagating in only in the side waveguides (after the 3x3 directional coupler) of the Mach-Zehnder interferometer propagate and interfere in the 3x3 directional coupler (on the return path), while a light wave in the center waveguide does not participate in interference, because it is unused. 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 Mach-Zehnder interferometer of the Kawachi – Rahman combination can be configured as a particular case of 2-beam interference, as illustrated by Takada, when light waves propagating in only in the side waveguides of the Mach-Zehnder interferometer propagate and interfere in the output directional coupler, while a light wave in the center waveguide does not participate in interference.
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The optical waveguide device of the Kawachi – Rahman – Takada combination is illustrated in Figure A below, which is produced from Fig. 24A of Kawachi by disrupting/truncating the center waveguide, according to the illustration in Fig. 1 of Takada.
Figure A. The optical waveguide device of the Kawachi – Rahman – Takada combination.
The Kawachi – Rahman – Takada combination considers that a light wave in the center waveguide does not participate in interference (because it is unused), and Takada appears to show that the light wave is radiated out of the center waveguide into free space. While the Kawachi – Rahman – Takada combination does not further detail such arrangement, Kondou discloses (Figs. 1, 2, 6, and 7; Abstract; para. 0040 – 0044 and 0055 – 0057) an optical waveguide branch/splitter that is comprised in a Mach-Zehnder interferometer and produces an unnecessary/undesirable light wave (radiation light). Kondou expressly teaches that such unnecessary light can be mitigated/eliminated by an unnecessary light beam removing unit (a machined hole and/or an electrode) that causes a light wave propagating through a central area to be absorbed (by the electrode) or to be radiated outside (by a machined hole) and is provided on an output side of the optical waveguide branch/splitter.
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 waveguide device (modulator/switch) of the Kawachi – Rahman – Takada combination can be modified, in accordance with the teachings of Kondou, to further comprise an unnecessary light beam removing unit that causes a light wave propagating through the center waveguide to be absorbed or to be radiated outside the optical waveguide device is provided on an output side of the directional coupler. The motivation for such unnecessary light beam removing unit is that is suppresses the light in the center waveguide and prevents it from interfering with the lights in the side waveguides (as intended by the Kawachi – Rahman – Takada combination).
Regarding claim 7, the Kawachi – Rahman – Takada – Kondou combination considers that any two of the three waveguides may be used for interference and/or detection. As a particular case, the center waveguide and one side waveguide may be use, while light in the other side waveguide is absorbed or to be radiated outside the optical waveguide device.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Kawachi in view of Rahman, in view of Takada.
Regarding claim 8, the teachings of Kawachi, Rahman, and Takada combine (see the arguments and motivation for combining, as provided above for claim 5) to teach expressly or render obvious all of the recited limitations. Specifically, the Kawachi – Rahman – Takada combination considers a guide unit (side waveguides after the output 3x3 coupler, as shown in Figure A provided above for claim 5) that guides at least a part of a light wave propagating through the side waveguides to a photo detection unit (a balanced photodetector) is provided on an output side of the directional coupler (according to Fig. 1 of Takada).
Claims 11 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Kawachi in view of Rahman, and further in view of Sugiyama (US 2013/0243363 A1).
Regarding claims 11 and 12, the Kawachi – Rahman combination considers the optical waveguide device (electro-optic switch/modulator, according to Rahman) includes a modulation electrode for modulating a light wave propagating through the optical waveguide (“Voltage, applied to the electrodes deposited on the integrated Mach-Zehnder interferometer, creates an electric field distribution within the substrate, which consequently changes its refractive index. If properly designed, the induced change in the refractive index leads to different coupling between individual ports” in the Abstract of Rahman). While the Kawachi – Rahman combination does not detail a suitable source for providing a modulation signal to the electrode, Sugiyama discloses (Fig. 10; para. 0059 and 0060) an optical modulation module 62 that is packaged within a transmitting device 61 and driven by an electronic circuit 63 (driver amplifier) that amplifies a modulation signal to be input into the modulation electrode of the optical waveguide device (para. 0021) and is provided inside the case of the transmitting device 61. 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 waveguide device (electro-optic switch/modulator) of the Kawachi – Rahman combination can be co-packaged with an electronic circuit 63 (driver amplifier) that amplifies a modulation signal and enable an integrated transmitting module.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 2008/0025662 A1
US 2014/0355924 A1
US 10,041,797 B2
US 5,394,239
US 8,831,385 B2
US 9,081,214 B2
US 5,289,256
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ROBERT TAVLYKAEV whose telephone number is (571)270-5634. The examiner can normally be reached 10:00 am - 6:00 pm, Monday - Friday.
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/ROBERT TAVLYKAEV/Primary Examiner, Art Unit 2896