DETAILED ACTION
Claim Objections
Claim 12 is objected to because of the following informalities: claim 12 recites a limitation already disclosed in claim 1. Appropriate correction is required.
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, 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.
Claim(s) 1-4, 8-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over U.S. PGPub 2021/0041649 A1 by Brusberg et al., in view of U.S. PGPub 2003/0138216 A1 by Shimoda.
Regarding claim 1, Brusberg teaches an optical circuit board (integrated circuit package 200, Fig. 2A) comprising: a wiring board (dielectric layers 234 with redistribution layers 236) comprising an upper surface (on which an glass waveguide/article 220 is disposed); and an optical waveguide (spot size converter 440 as shown in Fig. 3), wherein a part of the upper surface of the wiring board is a mounting region of an optical component (optical channel 232, integrated circuit chip 260), the optical waveguide is positioned adjacent to the mounting region of the optical component on the wiring board (as illustrated in Fig. 2A) and comprises a core (interior rib 452, e.g., higher index material Si, ¶[0046])), a first cladding (positioned at an expanded optical mode portion 442 of the converter, including a capping portion 448 below the rib 452 and a surrounding body 450 above the rib 452, it is noted while the capping portion 448 and the surrounding body 450 are not referred to as cladding, they are present to insure “transmissive to the photonic energy that is transferred through the optical spot size converter 440”, ¶[0045], i.e., they function as claddings to ensure total internal reflection), and a second cladding (positioned at a reduced optical mode portion 444 of the converter, including the capping portion 448 below the rib 452 and the surrounding body 450 above the rib 452), the core comprises a first portion (positioned at the expanded optical mode portion 442) having a first upper surface and a first lower surface (top and bottom surfaces of the rib 452 at the portion 442) and a second portion (positioned at the reduced optical mode portion 444) having a second upper surface and a second lower surface (top and bottom surfaces of the rib 452 at the portion 442), the first cladding is positioned (at the portion 442) sandwiching the first upper surface and the first lower surface of the first portion of the core, the second cladding is positioned (at the portion 444) sandwiching the second upper surface and the second lower surface of the second portion of the core, a width of the second portion is greater than a width of the first portion (the interior rib tapers from the reduced mode portion 444 to the expanded mode portion 444, ¶[0049] and as illustrated in Fig. 3), a thickness of the second portion is greater than a thickness of the first portion (the tip width of the interior rib 452 when evaluated at the reduced mode optical portion 444 is about four times as thick as the tip width at when evaluated at the expanded mode optical portion 442, ¶[0049]).
Brusberg does not teach different refractive indices of the cladding at the different portions of the spot size converter. Shimoda also teaches a spot size converter (Fig. 11A) comprising a core (42) sandwiched between cladding layers (first through fourth claddings 411, 412, 413, 414), respectively, wherein the spot size is enlarged from the first cladding (411) toward the fourth cladding 414), and the core layer had the refractive index n(0) of 1.475, and the values of the refractive index n(1) to n(4) were 1.446, 1.453, 1.460 and 1.468, respectively. That is, coupling to larger spot size corresponds to larger refractive index of the cladding (or a smaller index difference between the core and cladding), and this trend is also observed and illustrated in Fig. 12A, in which a width of the core increases with decreased core/cladding index difference. It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Brusberg’s invention, by using successive claddings of increased refractive index (i.e., a smaller index difference between the core and cladding) with an increased size of the core, as suggested by Shimoda. This design resolves a problem of a larger difference in specific refractive index (e.g., Si core and silica cladding as stated in Brusberg) by reducing the coupling length and consequently the overall size of the spot size converter. (Shimoda, ¶[0021])
Regarding claim 2, Brusberg further teaches the core comprises a tapered portion between the first portion and the second portion, a width and a thickness of the tapered portion decreasing from an end portion of the second portion toward an end portion of the first portion (as illustrated in Fig. 3 and described in ¶[0049]).
Regarding claim 3, Shimoda further suggest the first cladding positioned on the first lower surface side of the first portion comprises a groove along an end portion of the first portion on the optical component side (Fig. 20E, into which a portion of upper clad layer 1122 is inserted, so as to separate first and second core layers 1133/1134).
Regarding claim 4, Brusberg further teaches a first cladding upper surface of the first cladding positioned on the first upper surface side of the first portion is flush with a second cladding upper surface of the second cladding positioned on the second upper surface side of the second portion (upper surfaces are all flush since Brusberg uses a continuous taper (Fig. 3); Shimoda also suggests flushed upper surfaces of the core (Fig. 11A), for the purpose of limiting interfacial optical loss).
Regarding claim 8, Brusberg further teaches the first upper surface of the first portion is flush with the second upper surface of the second portion, and a center of the width of the first portion and a center of the width of the second portion coincide with each other in a plan view (surfaces are all flush since Brusberg uses a continuous taper as illustrated in Fig. 3).
Regarding claim 9, Brusberg further teaches a central axis of the first portion and a central axis of the second portion are coaxial with each other (since Brusberg uses a continuous taper (Fig. 3); Shimoda also suggests a single continuous core 42 (Fig. 11A), for the purpose of limiting interfacial optical loss).
Regarding claim 10, Brusberg further teaches a cross section of the first portion and a cross section of the second portion each have what appears to be a rectangular shape. However, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to select a square shape for the cross-section of the core, since the modification does not appear to result in any functional difference that can be relied upon to patentably distinguish the claimed invention from prior art. In re Seid, 73 USPQ 431.
Regarding claim 11, Brusberg further teaches a conductor (of the redistribution layers 236) is positioned between the wiring board (234) and the optical waveguide (440).
Regarding claim 12, Brusberg further teaches an optical component (silicon-based integrated circuit chip 260) mounted in the mounting region.
Regarding claim 13, Brusberg the optical component is a silicon photonics device, the silicon photonics device comprises a silicon waveguide, and the silicon waveguide is positioned facing the first portion of the core (a silicon wire waveguide that is embedded in a silicon-based integrated circuit chip, ¶[0050]).
Allowable Subject Matter
Claims 5-7 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Relevant prior art fails to teach or suggest specific positioning of the first and second claddings, including the first cladding positioned on the first upper surface side of the first portion covers a part of the second cladding upper surface of the second cladding positioned on the second upper surface side of the second portion, or the second cladding positioned on the second upper surface side of the second portion covers a part of the first cladding upper surface of the first cladding positioned on the first upper surface side of the first portion, or the second cladding positioned on the second lower surface side of the second portion extends between the wiring board and the first cladding positioned on the first lower surface side of the first portion, when considered in view of the rest of the limitations of the claimed invention.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US 20130287354 discloses a device including a tapered waveguide (Fig. 16) combined with an electrical wiring board; JP2007093743 discloses a spot size conversion waveguide.
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/CHARLIE Y PENG/Primary Examiner, Art Unit 2874