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
Applicant’s amendments and remarks filed 4/13/26 are acknowledged. Claims 1, 5 – 8, and 7 have been amended; claims 2 and 4 canceled; and claims 13 – 17 added. Claims 1, 3, and 5 – 17 are pending.
Response to Amendments / Arguments
Applicant's amendments have obviated the previously-raised rejections under 35 USC 102 and necessitated new rejections under 35 USC 103, as detailed below, to address the new limitations in claims 1 and 5 that define a truncated center waveguide. As correctly noted by Applicant with respect to Kawachi, “the three optical waveguides 82, 83 and 84 are formed continuously from one end to the other of the substrate 40” (3rd para. on p. 9 of Remarks, emphasis added). Accordingly, the Examiner applies a reference by Lefevre (US 2014/0340690 A1) that has been yielded by an updated prior art search and discloses a bidirectional 3x3 coupler that can operate as a 50:50 splitter and/or a 50:50 combiner and has a a truncated center waveguide.
Applicant's arguments regarding the amended claims versus the previously-raised rejections under 35 USC 103(a) have been fully considered but they are moot in view of the new grounds of rejections, as necessitated by Applicant’s amendments which incorporated the limitations of cancelled claims 2 and 4 and added new limitations that define a truncated center waveguide that starts/ends at a location different from that of the side waveguides. Accordingly, the Examiner applies the Lefevre reference in combination with other prior art of record to cover the limitations recited by the amended claims.
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, 3, 6, and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Lefevre (US 2014/0340690 A1), as evidenced by “A three-waveguide polarization independent power splitter on lithium niobate substrate” by Ganguly et al, Optics Communications, vol. 168, pp. 349–354, 1999 (hereinafter Ganguly).
Regarding claim 1, Lefevre discloses (Figs. 8, 10A, and 11; Abstract; para. 0053 – 0058, 0066, and 0067; see annotated Figs. 10A and 11 below) an optical waveguide device 40 (a 3x3 optical waveguide coupler that is configured for bidirectional operation as a 50:50 splitter/combiner; para. 0001, 0053, 0054, and 0060) comprising an optical waveguide 31,32,33 formed on a substrate (e.g., a lithium niobate substrate; para. 0053),
wherein a directional coupler 35 is disposed in a part of the optical waveguide 31,32,33, the directional coupler 35 includes one center waveguide 31 and two side waveguides 32,33 disposed to interpose the center waveguide 31 between the side waveguides 32,33 (as seen in Figs. 8 and 10A; “ The optical integrated circuit comprises a 3.times.3 coupler, comprising an evanescent-field coupling zone 35 in which three single-mode waveguides 31, 32, 33 are arranged preferentially parallel to each other. Two lateral waveguides 32, 33 are arranged symmetrically with respect to a central waveguide 31” at para. 0053), the side waveguides 32,33 are disposed to come close to the center waveguide 31 (going left to right in Figs. 8 and 10A) from a position (input port Pa) where the side waveguides 32,33 are separated from the center waveguide 31 and then to be separated again from the center waveguide 31 (at output port Pb; “Outside the optical coupling zone 35, the first waveguide 31, the second waveguide 32 and the third waveguide 33 go away from each other between each of the input ports, respectively Pa, Pe, Pf, and the optical coupling zone 35. Likewise, the first waveguide 31, the second waveguide 32 and the third waveguide 33 go away from each other between the optical coupling zone 35 and each of the output ports, respectively Pb, Pc, Pd” at 0058) in a traveling (horizontal left-to-right) direction of a light wave (as seen in Figs. 8 and 10A), and the center waveguide 31 and the side waveguides 32,33 (as seen in Fig. 10A) are not in contact with each other,
the directional coupler 40 functions as a branching waveguide that introduces a light wave 36 (with power P) from one (left) side of the center waveguide 31 (as shown in Fig. 10A) and that derives the light wave 42,43 (with power P/2) branching from (each of) the two side waveguides positioned on the other (right) side of the center waveguide 31 (Fig. 10A; para. 0055), and
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a starting (left) end of each of the two side waveguides 32,33 is located on an input (left) side of the directional coupler 35, and an ending (right) end of the center waveguide 31 is located on an output (right) side of the directional coupler 35.
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Annotated Figs. 10A and 11 of Lefevre.
While Lefevre illustrates, by way of example but not limitation, that the waveguides 31, 32, 33 all start/end at a same input/output location/distance from the coupled region 35, Lefevre states a (well-known) property of directional couplers that “The beams guided in the different waveguides 31, 32, 33 propagate in a guided and independent manner in each waveguide 31, 32, 33, outside the optical coupling zone 35” (para. 0058, emphasis added). Hence, Lefevre renders obvious that the length of each of the 3 waveguides 31,32,33 can be extended or shortened by any amount, as needed for a particular application/layout, and the side waveguides 32,33 can start and end at locations different/offset from those of the center waveguide along the propagation direction of light. Furthermore, Fig. 11 (see annotated Fig. 11 provided above) of Lefevre illustrates that the center waveguide of the directional coupler 40b has a waveguide/fiber extension 108 of the center waveguide (para. 0066), the waveguide/fiber extension 108 providing input light to a fiber coil 102 and collecting light returning from it. Thus, Lefevre considers that a distance (denoted as distance A in annotated Fig. 11) between the center waveguide 31 and the starting (left) end of each of the side waveguides 31,32 before coming close to the center waveguide 31 (with the region 35) is the length of the waveguide/fiber 108 which is much longer (e.g., twice or more) than a mode diameter of a light wave propagating through the optical waveguide: indeed, Lefevre illustrates (Fig. 10A) another (well-known) property of optical waveguides that an optical waveguide mode (any one of 36,42,43 in Fig. 10A) has a diameter comparable to that of the corresponding waveguide core diameter/size.
Figure 11 of Lefevre also shows that the side waveguides 32,33 of the output side of the 3x3 coupler 40b are extended by additional optical waveguide segments (modulated by electrodes 106,107; para. 0066). Thus, Lefevre considers that a distance (denoted as distance B in annotated Fig. 11) between the ending (right) end of the center waveguide 31 and the side waveguides 32,33 after being separated from the center waveguide 31 can be set to be twice or more of a mode diameter of a light wave propagating through the optical waveguide 31,32,33.
Ganguly describes a 3x3 directional coupler having features similar to those in Lefevre and provides evidence for the above-noted well-known properties of optical waveguides and directional coupler comprising thereof:
(1) A mode diameter of a light wave propagating through an optical waveguide is comparable to its width (e.g., a mode diameter of ~ 15 mm in Fig. 3 is comparable to an effective waveguide width of ~ 10 mm, after a 6.5 mm Ti strip is in-diffused and widened by side diffusion); and
(2) The center waveguide 1 can start well before the region of evanescent coupling and the starting end of the side waveguides 2,3 (e.g., to the left by a distance of 2.0 mm in Fig. 1) and the side waveguides 2,3 can extended well beyond the region of evanescent coupling (e.g., to the right by a distance of 2.0 mm in Fig. 1) and beyond the ending end of the center waveguide 1. Distances of 2 – 5 mm are much greater than twice the mode diameter (of ~ 15 mm in Fig. 3).
Regarding claim 6, Lefevre teaches that the disclosed directional coupler is a bidirectional device and can function as a light branching device (as in Fig. 10A; para. 0055 – 0558) for the left-to-right direction of light propagation and as a light combining device (as in Figs. 10B and 10 C; para. 0059 – 0062) for the reverse direction of light propagation. Lefevre meets all of the recited limitations of a light combining device. Specifically, Lefevre (Figs. 8, 10A, and 11; Abstract; para. 0053 – 0058, 0066, and 0067; see annotated Figs. 10A and 11 provided above for claim 1) an optical waveguide device 40 (a 3x3 optical waveguide coupler that is configured for bidirectional operation as a 50:50 splitter/combiner; para. 0001, 0053, 0054, and 0060) comprising (see annotated Fig. 10A provided above for claim 1 but with the reverse direction of light propagation, as shown in Figs. 10B and 10C):
an optical waveguide 31,32,33 formed on a substrate (e.g., a lithium niobate substrate; para. 0053),
wherein a directional coupler 35 is disposed in a part of the optical waveguide 31,32,33, the directional coupler 35 includes one center waveguide 31 and two side waveguides 32,33 disposed to interpose the center waveguide 31 between the side waveguides 32,33 (as seen in Figs. 8 and 10A; “ The optical integrated circuit comprises a 3.times.3 coupler, comprising an evanescent-field coupling zone 35 in which three single-mode waveguides 31, 32, 33 are arranged preferentially parallel to each other. Two lateral waveguides 32, 33 are arranged symmetrically with respect to a central waveguide 31” at para. 0053),
the side waveguides 32,33 are disposed to come close to the center waveguide 31 (going right to left in Figs. 8, 10B, and 10C) from a position (right ports Pb, Pc, Pd) where the side waveguides 32,33 are separated from the center waveguide 31 and then to be separated again from the center waveguide 31 (left ports Pa, Pe, Pf; “Outside the optical coupling zone 35, the first waveguide 31, the second waveguide 32 and the third waveguide 33 go away from each other between each of the input ports, respectively Pa, Pe, Pf, and the optical coupling zone 35. Likewise, the first waveguide 31, the second waveguide 32 and the third waveguide 33 go away from each other between the optical coupling zone 35 and each of the output ports, respectively Pb, Pc, Pd” at 0058) in a traveling (horizontal right-to-left) direction of a light wave (as seen in Figs. 10B and 10C), and the center waveguide 31 and the side waveguides 32,33 (as seen in Fig. 10A) are omitting contact with each other,
the directional coupler 40 functions as a combining waveguide (as shown in Figs. 10B and 10C) that introduces two light waves 52,53 (as denoted in Fig. 10B) into each side waveguide from the one (right) side of the two side waveguides 32,33 and that derives a light wave 61 into which the two light waves 52,53 are combined from the center waveguide 31 positioned on the other (left) side of the side waveguides 32,33,
a starting end of the center waveguide 31 is located on an input (right) side of the directional coupler 40, and an ending end of each of the side waveguides 32,33 is located on an output (left) side of the directional coupler 40, and
a distance (distance B) between the starting end of the center waveguide 31 and each of the side waveguides 32,33 before coming close to the center waveguide and a distance (distance A) between the center waveguide 31 and the ending end of each of the side waveguides 32,33 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 31,32,33 (as detailed above for claim 1).
Regarding claims 3 and 17, Lefevre teaches (see annotated Figs. 10A provided above for claim 1) an intensity of optical confinement (a 3-lobe merged light distribution of coupled waveguides with the evanescent coupling region 35) of the optical waveguide 31,32,33 in any of the center waveguide 31 or the side waveguides 32,33 is weaker in a state where the center waveguide 31 and the side waveguides 32,33 are close to each other (with the evanescent coupling region 35) than in a state (individual modes 36, 42, and 43) where the center waveguide 31 and the side waveguides 32,33 are separated from each other: Figs. 10A illustrates a (well-known) property of directional waveguides to form composite modes with the evanescent coupling region.
Claims 5, 7, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Lefevre in view of Jain (US 10,041,797 B2).
Regarding claims 5 and 7, Lefevre considers (Fig. 10A; Abstract) that there can be a small amount of unnecessary/residual light (less than a few percent; Abstract) in the center waveguide 31 (“one secondary beam 41 of almost-null residual power (e << 1) propagates” at para. 0055). While Lefevre does not teach 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, Jain describes (Figs. 3a and 3b; 6:10 – 51) a device having structural features similar to those in Fig. 11 of Lefevre and comprising a bidirectional 3x3 waveguide coupler 101 (comprising a center waveguide 107 and side waveguides 104,105) operating as an input splitter (going from a light source 109 to a fiber coil 110). Jain expressly teaches an unnecessary light beam removing unit 114 (absorber) that causes a light wave propagating through the center waveguide 107 (center fiber that receives light from the optical source) to be absorbed or to be radiated outside the optical waveguide device is provided on the output (right) side of the directional coupler 101. Another absorber 115 is disposed at the other (left) end of the center waveguide 107 (as shown in Fig. 3a; “The end of central waveguide, opposite to SLD 109 is interfaced with an absorber 114 to eliminate scattering of light traveling outside of the 3×3 coupler 101. In one embodiment, a waveguide arm of the 2×2 directional coupler 109 is interfaced with the absorber region 115, particularly the waveguide whose other end is interfaced with PD3 106” at 6:35 – 41).
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 (waveguide interferometer) of Lefevre can be modified, in accordance with the teachings of Jain, 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 residual/unintended light in the center waveguide and prevents it from interfering with the lights in the side waveguides, so that an even 50-50 split/combining is accomplished, as intended by Lefevre.
Regarding claim 8 the Lefevre – Jain combination considers (Fig. 3A of Jain) that the optical device further comprises a guide unit (integrated optical waveguides coupled to photodetectors 102,103) that guides at least a part of a light wave propagating through the side waveguides of the 3x3 coupler 101 to a photo detection unit 102,103 is provided on the output side of the directional coupler 3x3 (the left side of the 3x3 directional coupler 101 operating as a light combining device, as detailed above for claim 6).
Claims 9 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Lefevre in view of Patel et al (US 2007/0253662 A1).
Regarding claims 9 and 16, Figure 11 of Lefevre illustrates, by way of example but not limitation, the use of the disclosed 3x3 directional coupler 40 as a building block, drop-in element and an input/output coupler of a Sagnac interferometer. While a Mach-Zehnder interferometer is another (well-known) interferometer type, Lefevre does not expressly teach a Mach-Zehnder interferometer with 3x3 directional couplers as input and output couplers. However, Patel discloses (Figs. 26 – 28; para. 0189 – 0198) a 3x3 directional coupler 120 configured as an input coupler and a 3x3 directional coupler 121 as an output coupler (for the left-to-right direction of light propagation from 120 to 121) of a Mach-Zehnder interferometer (claim 43). Each of the 3x3 directional couplers is formed by waveguides/fibers and has a structure/layout similar/identical to that in Figs. 8, 10, and 11 of Lefevre.
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 3x3 directional coupler 40 of Lefevre can be deployed as a building block, drop-in element and an input/output coupler of a Mach-Zehnder interferometer, as a suitable/workable application (device type) and as expressly taught and explicitly illustrated by Patel.
For the left-to-right direction of light propagation from 120 to 121 in Fig. 26 of Patel, the first directional coupler 120 is incorporated in at least one of a branching part or a Y-junction of the Mach-Zehnder type optical waveguide, while the second directional coupler 121 is incorporated in the merging/combining part the Mach-Zehnder type optical waveguide. The 3x3 directional couplers 120,121 reverse/swap their roles for the opposite direction of light propagation.
Claims 10 – 15 are rejected under 35 U.S.C. 103 as being unpatentable over Lefevre in view of Patel, and further in view of Sugiyama (US 2013/0243363 A1).
Regarding claims 10 and 13, the Lefevre – Patel combination considers a Mach-Zehnder type optical waveguide comprising 3x3 directional couplers as input and output couplers (as detailed above for claims 9 and 16). While the Lefevre – Patel combination does not detail further structural particulars (such as a case/housing) and high-speed applications of such device, Sugiyama discloses (Figs. 1, 5, 8 and 10; para. 0019 – 0021, 0049 – 0054, 0059 and 0069) a Mach-Zehnder type optical waveguide that is configured for a high-speed modulator (Fig. 6; para. 0005) and formed by couplers 2,5. Sugiyama expressly teaches that the modulator device comprises a case accommodating the optical waveguide device (para. 0059 and 0060); and an optical fiber 64 (shown in Fig. 10; para. 0060) through which a light wave is input into the optical waveguide or output from the optical waveguide.
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 type optical waveguide comprising 3x3 directional couplers as input and output couplers, as contemplated by the Lefevre – Patel combination, can be implemented as a high-speed modulator, as a suitable/workable application illustrated by Sugiyama. The device is accommodated/disposed in a case in order to be sealed from an environment and be mechanically rugged.
Regarding claims 11, 12, 14, and 15, the Lefevre – Patel – Sugiyama combination considers that the optical waveguide device (high-speed modulator) includes a modulation electrode for modulating a light wave propagating through the optical waveguide (para. 0021 and 0033 – 0036 of Sugiyama), wherein the modulation electrode is 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 (high-speed electro-optic switch/modulator) of the Lefevre – Patel – Sugiyama 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 8,395,782 B2 Figs. 1, 3 – 10
“Refractive Index Sensing Using a Three-Port Interferometer and Comparison With Ring Resonators” by Gulik et al, IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, vol. 23, No. 2, paper 8200207, 2017 Fig. 1
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
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
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