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, 6, and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Hiraki et al (US 2020/0400977 A1) in view of Kawanishi et al (US 2012/0162656 A1).
Regarding claim 1, Hiraki discloses (e.g., Figs. 1C; Abstract; para. 0026 – 0039) an optical circuit formed on a silicon substrate 102 (para. 0020), the optical circuit comprising:
an optical waveguide modulator in which a PN junction is formed in a cross section (between oppositely doped regions 131,132; para. 0038 and 0039) of an optical waveguide with a rectangular waveguide core.
Hiraki states that the optical waveguide modulator is a phase modulator (para. 0031), but does not illustrate its application, as a drop-in element, in a Mach-Zehnder interferometer type modulator. However, Kawanishi discloses (Figs. 1 – 3; Abstract; para. 0049 – 0094) a Mach-Zehnder interferometer type modulator that comprises a phase modulator in each arm of the two arm waveguides that make up the interferometer (“Each of the two arms functions as a phase modulator” at para. 0048). 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 phase modulator of Hiraki can be comprised, as a drop-in element, in each waveguide arm of a Mach-Zehnder interferometer type modulator, as a well-known arrangement that is illustrated by Kawanishi and converts phase modulation in amplitude/intensity modulation (para. 0068 of Kawanishi).
The Hiraki – Kawanishi combination considers an optical circuit formed on a silicon substrate 101 (Fig. 1C; para. 0028 of Hiraki), the optical circuit comprising:
a Mach-Zehnder interferometer type modulator including two arm waveguides (one of the nested Mach/Zehnder interferometers in Figs. 1 – 3 of Kawanishi) in which a PN junction is formed in a cross section; and
an inspection circuit for the modulator, including:
an input section (including split output of a splitter 33 in Fig. 3 of Kawanishi) for receiving test light (para. 0059 – 0099), the input section including a rectangular waveguide (according to Fig. 1C of Hiraki);
at least one inspection waveguide (one waveguide arm or both waveguide arms of any other Mach-Zehnder interferometer type modulator coupled to the splitter 33 in Fig 3 of Kawanishi) being connected to the rectangular waveguide, in parallel to the two arm waveguides, and having a PN junction having the same configuration as the PN junction of at least one of the arm waveguides (the Mach-Zehnder interferometer type modulators receiving light from the splitter 33 are designed to be identical); and
an optical branch (an input Y-branch) of the other Mach-Zehnder interferometer type modulator) for splitting the test light to two branch light beams having equal intensity and propagating the two branch light beams to the inspection waveguide, the optical branch including a rectangular waveguide (according to Fig. 1C of Hiraki).
In light of the foregoing analysis, the Hiraki – Kawanishi combination teaches expressly or renders obvious all of the recited limitations.
Regarding claims 6 and 7, the Hiraki – Kawanishi combination renders obvious that a configuration of a PN junction in a cross section of a first arm waveguide of the two arm waveguides and a configuration of a PN junction in a cross section of a second arm waveguide are symmetric/mirrored or the same with respect to a center line of the two arm waveguides parallel to a light propagation direction (depending on an intended polarity of modulating signals to be applied to the two waveguide arms). The Hiraki – Kawanishi combination also renders obvious the inspection of the first arm waveguide and the second arm waveguide by either a common inspection circuit (applying a same voltage to both waveguide arms) or separate inspection circuits (applying independent/different voltages to the two waveguide arms).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Hiraki et al in view of Kawanishi, and further in view of Gunn et al (US 2006/0008223 A1).
Regarding claim 5, Hiraki illustrates rib-shaped (rectangular) waveguide cores, but does not illustrate ridge-shaped core with slab regions. However, Gunn illustrates both a rectangular waveguide core 220.230 in a semiconductor material (Fig. 2) and a ridge-shaped core 112 with slab regions120,130 in a semiconductor material (Fig. 1). 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 two arm waveguides are rib waveguides, and the rectangular waveguide is a (passive) ridge-type waveguide not including a PN junction or the other way around.
As a relevant comment, it is noted that Applicant uses a non-standard/reversed terminology and terms “rib waveguides” ridge-shaped cores with slab regions. A rectangular waveguide is a rib waveguide, not a ridge waveguide.
Allowable Subject Matter
The subject matter pertaining to claims 2 – 4 would be allowable, if Applicant overcomes rewrites them in independent form including all of the limitations of the base claims and any intervening claims.
The reason for indicating allowable subject matter is that none of the prior art of record, taken alone or in combination, teaches expressly, renders obvious, and provides a motivation for bidirectional light propagation in an inspection waveguide (as shown in Figs. 9, 11, and 12 of the instant application) so that its length is reduced down to a half the arm length of a Mach-Zehnder modulator under testing (as recited by claims 2 and 3) in order to equalize their effective propagation lengths. If the inspection waveguide is folded and separated in 4 segments 60-1,60-2,60-3,60-4 (as in Fig. 12), the length of the inspection waveguide is reduced to 1/4 of the arm length of the Mach-Zehnder modulator under testing (as recited by claim 4).
As was noted by the Examiner during the 9/30/26 interview, the removal of the limitation (compared to the originally presented claims of 10/30/24) defining bidirectional light propagation through the inspection art broadened the scope of the claims enough for some prior art yielded by a prior-art search to be applicable, as detailed above for the rejections under 35 USC 103. An amendment undoing the limitation removal would eliminate the applicability of such prior art.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 2024/0231176 A1 Fig. 1 – 4 show a Mach-Zehnder modulator with a rectangular waveguide core.
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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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, William Kraig can be reached on (571)272-8660. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/ROBERT TAVLYKAEV/Primary Examiner, Art Unit 2896
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