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 5/12/26 are acknowledged. Claims 1, 8, 12, 15, and 18 have been amended and claim 17 canceled. Claims 1 – 16 and 18 – 21 are pending.
Response to Amendments / Arguments
Applicant's arguments regarding the amended claims versus the previously-raised rejections under 35 USC 103(a) have been fully considered but they are not persuasive. Furthermore, the arguments are moot in view of the new grounds of rejections, as necessitated by the Applicant’s amendments. While Applicant argues that the applied prior art does not meet the new limitation in claim 1, the Examiner respectfully disagrees and details below how Cheung renders obvious an embodiment meeting the new limitation. Furthermore, given Applicant’s emphasis on such limitation, the Examiner additionally applies a reference by Kim et al (US 2022/0011641 A1) that has been rendered obvious by an updated prior art search and explicitly illustrates a similar modulator structure wherein a doped structure overlying a cladding layer has a width less than that of the cladding layer.
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 – 7 are rejected under 35 U.S.C. 103 as being unpatentable over Cheung et al (US 2022/0091446 A1) in view of Gill (US 2008/0159680 A1), and further in view of Kim et al (US 2022/0011641 A1).
Regarding claim 1, Cheung discloses (Figs. 1, 2, and 4; Abstract; para. 0017 – 0031 and 0042 – 0045) a method of manufacturing an optical device (an optical waveguide coupler/modulator), the method comprising (see annotated Fig. 4 below):
forming a first dopant region 406,408 (P-type doped) over a substrate 402, the first dopant region 406,408 comprising a first waveguide 407 and a second waveguide 409 (“the reference numerals 407 and 409 respectively represent a first optical waveguide and a second optical waveguide” at para. 0044);
depositing a cladding material 410 over the first waveguide 407 and the second waveguide 409 (as seen in Fig. 4; “the second insulating layer 410” at para. 0044); and
forming a second dopant region 416 (N-type doped) overlying the first waveguide 407 and the second waveguide 409 (as seen in Fig. 4), wherein the forming the second dopant region comprises forming a first (central) region extending over both the first waveguide 407 and the second waveguide 409, the first (central) region having a concentration of a first (N-type) dopant (the ends of 416 are doped at N++ and there is no teaching/indication of a dopant polarity reversal, as opposed to the embodiment in Fig. 3).
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Annotated Fig. 4 of Cheung.
While Cheung generally renders obvious that the first (central) region can be configured to have a constant concentration of the first (N-type) dopant, Cheung does not expressly teach such arrangement. However, Gill discloses (Figs. 1, 2, and 4 – 9; para. 0015 – 0046 and 0049 – 0064) a method of manufacturing an optical device (an optical waveguide modulator), the method comprising:
forming a first dopant region 520,610,620 (e.g., P-type doped; para. 0055) over a substrate 410, the first dopant region 520,610,620 comprising a waveguide 520 (ridge-shaped waveguide (para. 0053), which is the same type as in Cheung); and
forming a second dopant region 810,820,910,920 (N-type doped; para. 0061) overlying the waveguide 520 (as seen in Fig. 9), wherein the forming the second dopant region 810,820,910,920 comprises forming a first region (a central region between 910 and 920) extending over both the waveguide 520, the first region having a constant concentration of a first (N-type) dopant at a low concentration level, according to the central region 155a,255a in Fig. 2 (“the relatively low doped region 155a has a dopant level at least ten times lower than a dopant level of the relatively higher doped region 155b” at para. 0028; “the fourth semiconductor slab 220 contains a relatively low doped region 225a proximate the ridge-shaped semiconductor optical core 130” at para. 0043).
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 (central) region in Cheung can be configured, as expressly taught by Gill, to have a constant low concentration of the first (N-type) dopant, so that the optical loss to a high dopant concentration can be avoided (para. 0004, 0014, and 0047 of Gill) by using low-concentration central region over the waveguides and placing heavily doped regions away from the waveguides: as seen in Fig. 2 of Gill, heavily-doped regions 155b and 225b are placed away from the waveguide 520 and correspond to the heavily doped (N++) ends of the second dopant region 416 in Fig. 4 of Cheung.
Further, Fig. 4 of Cheung shows, by way of illustration but not limitation, that after the forming the second dopant region the second dopant region 416 has a width about the same as that of the cladding material 410, Cheung does not require the two widths to be equal. In particular, Cheung broadly defines second dopant region 416 as “a semiconductor material layer disposed over the insulating layer” (Abstract; para. 0015 and 0023) and teaches that overlapping portion of the second dopant region 416 and the cladding material 410 form an optical waveguide (Abstract; para. 0015). Hence, Cheung renders obvious embodiments (design choices) wherein the second dopant region 416 has a width different from (less or greater than) that of the cladding material 410, in order to modify the properties (mode) of the optical waveguide. Besides, Fig. 4 of Cheung shows that other dielectric/insulating layers 418,425 extend across the entire device width, including locations of the outermost electrodes 424,430. It would be obvious that the cladding material 410 can also extend across the entire device width, in full similarity with the dielectric/insulating layers 418,425, as a suitable/workable design choice. Furthermore, Kim discloses (Figs. 3 – 7; para. 0065 – 0077) an optical waveguide modulator comprising a cladding material 23 disposed over an optical waveguide 22 and covered by a doped layer 24 (para. 0066), wherein the doped layer 24 has a width less than that of the cladding material 23, the cladding material 23 extending to, and interfacing with, a first electrical contact 31 (para. 0067). 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 second dopant region 416 in Cheung can have a width less than that of the cladding material 410, as generally rendered obvious by Cheung and explicitly illustrated by Kim.
In light of the foregoing analysis, the Cheung – Gill – Kim combination teaches expressly or renders obvious all of the recited limitations.
As an aside and relevant comment to all claims, it is also noted that the optical device of the Cheung – Gill – Kim combination has essential structural features (a 2x2 coupler formed a pair of optically coupled waveguides) and a principle of operation (an electro-optically tunable splitting ratio of optical power between the two waveguides by an applied voltage which creates a vertical flow of carriers) that are substantially similar/identical to those of the claimed device, as evident from a direct side-by-side comparison of Figs. 2 and 4 of Cheung and Figs. 8 and 9 of the instant application.
Regarding claim 2, the Cheung – Gill – Kim combination considers that the forming the second dopant region further comprises:
forming a second (peripheral) region (identified in annotated Fig. 4 provided above for claim 1) extending away from the first region, the second region having a higher concentration (N++) of the first (n-type) dopant than the first (central) region (it has a low concentration, according to Gill); and
forming a third region (peripheral) extending away from the first (central) region, the third region having a higher concentration (N++) of the first (n-type) dopant than the first (central) region (it has a low concentration, according to Gill).
Regarding claim 3, the Cheung – Gill – Kim combination considers that the method further comprises forming a first contact 426 to the second (peripheral) region; and forming a second contact 428 to the third (peripheral) region (“a second metal contact 426, a third metal contact 428” at para. 0043 of Cheung).
Regarding claim 4, the Cheung – Gill – Kim combination considers that the forming the first dopant region comprises forming a connective region (identified in annotated Fig. 4 provided above for claim 1) in physical contact with the first waveguide 407, the connective region having a smaller thickness than the first waveguide 407 (as seen in Fig. 4 of Cheung).
Regarding claim 5, the Cheung – Gill – Kim combination considers that the forming the first dopant region comprises forming a first contact region (peripheral region doped at P++) in physical contact with the connective region, the first contact region having a larger concentration (P++) of a second (P-type) dopant than the connective region (according to the teachings of Gill for the low-concentration regions 145a,215a in Fig. 2; para. 0024 and 0039).
Regarding claim 6, the Cheung – Gill – Kim combination considers that the first dopant is an n-type dopant and the second dopant is a p-type dopant.
Regarding claim 7, Cheung teaches that the optical device can operate as an electro-optic 2x2 beam splitter (Fig. 2; “the optical coupler 100 may be used as an optical splitter where the light signal may be transferred from the input port to a plurality of the output ports in a predetermined proportion” at para. 0017).
Claims 8 and 10 – 15 are rejected under 35 U.S.C. 103 as being unpatentable over Cheung in view of Gill, in view of Kim, and further in view of Jiang et al (US 2017/0255079 A1).
Regarding claim 8, the teachings of Cheung, Gill, and Kim combine (see the arguments and motivation for combining, as provided above for claim 1) to teach expressly or render obvious a method of manufacturing the contemplated optical device (an optical coupler and/or combiner), the method comprising (with reference to Fig. 4 of Cheung):
forming a first polysilicon material 416 (Cheung cites silicon as a suitable/workable material choice for 416 (para. 0023) and Gill cites polysilicon as a suitable/workable material choice (para. 0021)) overlying both the first waveguide 407 and the second waveguide 409, the first polysilicon material 416 having a constant (low) concentration (according to the teachings of Gill, as detailed above for claim 1) of a first (N-type) dopant, the first polysilicon material 416 extending over the coupler (as seen in Fig. 4).
The Cheung – Gill – Kim combination also considers a cladding material 410 over the first waveguide 407 and the second waveguide 409, the first cladding material 410 being a single material (e.g., SiO2, Si3N4, Al2O3, HfO2; para. 0022 of Cheung) throughout the first cladding material 410 and a first contact (at least one of 424,430). As detailed above for claim 1, the Cheung – Gill – Kim combination renders obvious a design choice wherein the cladding material 410 extends across the entire device width and the locations of the outermost electrodes 424,430 to interface with them, in full similarity with the dielectric/insulating layers 418,425 and with the embodiment illustrated in Fig. 3 of Kim.
Further, Cheung states that the disclosed coupler can be used as a (electro-optically tunable; Fig. 8) splitter and/or combiner (Fig. 2; “the optical coupler 100 may be used as an optical splitter where the light signal may be transferred from the input port to a plurality of the output ports in a predetermined proportion. In yet another example, the optical coupler 100 may be used as an optical combiner where light signals from a plurality of input ports may be combined into a single output port” at para. 0017) and that such couplers can be used in Mach-Zehnder interferometers (para. 0013), but Cheung does not explicitly illustrate such embodiment. However, Jiang discloses (Fig. 8; para. 0040) a Mach-Zehnder interferometer 80 comprising two elector-optically tunable couplers 10 (detailed in Fig. 1; para. 0025 – 0030), one of which operates a splitter and the other as a combiner. The Mach-Zehnder interferometer 80 comprises a first coupler 10 (e.g., left 10), a first modulating region (comprising a phase shifter 40), and a second coupler 10 (right) using a first waveguide 12 and a second waveguide 14.
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 coupler of the Cheung – Gill – Kim combination can be used, as a drop-in component, to enable a Mach-Zehnder interferometer, as a suitable/workable application illustrated by Jiang. The use of the electro-optically tunable coupler has the benefit of improving/increasing the extinction ratio of the Mach-Zehnder interferometer (para. 0040 of Jiang).
Regarding claim 10, the Cheung – Gill – Kim – Jiang combination considers (Fig. 4 of Cheung) that the first waveguide 407 comprises a P+ region.
Regarding claim 11, the Cheung – Gill – Kim – Jiang combination considers (Fig. 4 of Cheung) that the first polysilicon material 416 comprises an N+ region.
Regarding claim 12, the Cheung – Gill – Kim – Jiang combination considers (Fig. 4 of Cheung) forming a first contact 426 to a N++ region (peripheral portion of 416), the N++ region electrically connecting the first polysilicon material 416 to the first contact 426.
Regarding claim 13, the Cheung – Gill – Kim – Jiang combination considers (Fig. 4 of Cheung) comprising forming a second contact 424 to a P++ region (peripheral portion of 406), the P++ region electrically connecting the first waveguide 407 to the second contact 424.
Regarding claim 14, the Cheung – Gill – Kim – Jiang combination considers (Fig. 4 of Cheung) that the second contact 424 is located further from the first waveguide 407 than the first contact 426.
Regarding claim 15, the teachings of Cheung, Gill, Kim, and Jiang combine (see the arguments and motivation for combining, as provided above for claim 1 and 8) to teach expressly or render obvious all of the recited limitations, as detailed above for claims 1 and 8 Specifically, the Cheung – Gill – Jiang combination considers an optical device comprising (see annotated Fig. 4 of Cheung provide above for claim 1):
a first waveguide 407 over a substrate 402;
a second waveguide 409 over the substrate 402, wherein the first waveguide 407 and the second waveguide 409 form a first coupler (a 2x2 splitter corresponding to the left coupler 10 in Fig. 8 of Jiang), a modulation region (comprising a phase shifter 40), and a second coupler (the right coupler 10); and
a first polysilicon material 416 overlying both the first waveguide 407 and the second waveguide 409, the first polysilicon material having a constant (low) concentration of a first (N-type) dopant (according to the teachings of Gill (para. 0043) for the central region 155a,255a in Fig. 2), the first polysilicon material 416 extending over the first coupler (formed by 407,409); and
a first contact 424 in physical contact with a P++ region 406, the P++ region 406 in electrical connection with the first waveguide 407 (identified as the right rectangular dash-dotted area in Fig. 4), the first waveguide 407 extending further from the substrate 402 than at least a (bottommost) portion of the first contact 424.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Cheung in view of Gill, in view of Kim, in view of Jiang, and further in view of Wooten et al (US 2004/0240765 A1).
Regarding claim 9, while the Cheung – Gill – Kim – Jiang combination considers only a single-stage Mach-Zehnder interferometer (Fig. 8 of Jiang), multi-stage/cascaded Mach-Zehnder interferometers are also well known in the art. For example, Wooten discloses (Fig. 18; para. 0118) a two-stage/cascaded Mach-Zehnder interferometer comprising two Mach-Zehnder interferometers 1820a,1820b in series with each other, each Mach-Zehnder interferometer comprising a splitter, a combiner, and a modulating section.
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 coupler of the Cheung – Gill – Kim – Jiang combination can be implemented in a two-stage/cascaded Mach-Zehnder interferometer, as a suitable/workable application that is described by Wooten. The use of the electro-optically tunable couplers has the benefit of improving/increasing the extinction ratio of the Mach-Zehnder interferometer (para. 0040 of Jiang).
The corresponding method of manufacturing further comprises forming a third coupler, a second modulating region, and a fourth coupler in series with the first coupler, the first modulating region, and the second coupler.
Claims 16 and 18 – 21 are rejected under 35 U.S.C. 103 as being unpatentable over Cheung in view of Gill, in view of Lim, in view of Jiang, and further in view of Gunn et al (US 2006/0008223 A1).
Regarding claim 16, while the Cheung – Gill – Kim – Jiang combination considers (Fig. 2 of Gill) embodiments with a low-doped central region 155a,225a and a highly-doped peripheral region 155b,225b, and does not explicitly illustrate embodiments with more levels of dopant concentration, Gunn discloses an optical shifter and discloses both embodiment (Figs. 1 – 3) with two levels of dopant concentration on each side from the waveguide center and an embodiment (Figs. 11 and 12; para. 0068 – 0076) with at least three levels of dopant concentration.
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 coupler of the Cheung – Gill – Kim – Jiang combination can further comprise more doped regions with at least three levels of dopant concentration, such as N, N+, and N++ and P, P+, P++. The use of more levels of dopant concentration optimizes the trade-off between optical loss and electrical resistance (para. 0076 of Gunn).
The Cheung – Gill – Kim – Jiang – Gunn combination (CGKJG) considers that the first waveguide 407 comprises a P+ region and the first polysilicon material 416 comprises an N+ region.
Regarding claim 18, the CGKJG combination considers (Fig. 4 of Cheung) that the optical device can further comprise a second contact 428 in physical contact with an N++ region (left end of 416), the N++ region in electrical connection with the first polysilicon material 416.
Regarding claim 19, the CGKJG combination considers (Fig. 4 of Cheung) that the first contact 426 is located on an opposite side of the second contact 428 from the N++ region.
Regarding claim 20, the CGKJG combination considers (annotated Fig. 4 of Cheung) that the first waveguide 407 is adjacent to a P+ region (denoted as a connected region and doped at P+ according to Gunn), the P+ region having a smaller thickness than the first waveguide 407.
Regarding claim 21, the CGJG combination considers that the first waveguide 407 can comprise a doped portion (para. 0020, 0021, 0027, and 0043 of Cheung). Such doping is to be lighter than that of heavily doped (P++) region 406 to avid high optical loss (due to absorption of carriers) and can be P+.
Conclusion
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.
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/ROBERT TAVLYKAEV/Primary Examiner, Art Unit 2896
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