DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 05/27/2025 and 09102025 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statements are being considered by the examiner.
Response to Arguments
Applicant’s arguments with respect to claim(s) 1, 11, and 13 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
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, 2, 4, 5 and 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Fujikata et al. (US 10146070 B2) in view of Heideman et al. (US 9764352 B2).
Regarding claim 1: Fujikata et al. discloses an optical phase shifter comprising: a slab waveguide in which a first slab region (1130) doped into a first conductivity type (p-type) and a second slab region (1132) doped into a second conductivity type (n-type) are arranged side by side to form a PN junction (fig. 11); and a rib waveguide (1110) disposed on the slab waveguide, the rib waveguide including a first rib waveguide layer (1126 or alternatively 1126 and 1128 combined) adjacent to the slab waveguide, a second rib waveguide layer (1108) stacked on the first rib waveguide layer, and a third rib waveguide layer (1122) stacked on the second rib waveguide layer, wherein one side of the first rib waveguide layer makes contact with the first slab region (1130), and an opposite side of the first rib waveguide layer makes contact with the second slab region (1132) (Note: “makes contact” not overlaps; “makes contact” at one point is also “makes contact”), wherein the first rib waveguide layer (1126) and the third rib waveguide layer (1122) include silicon (Si), and wherein the second rib waveguide layer (1108) includes silicon-germanium (SiGe) (fig. 11).
Fujikata et al. is silent with respect to a thickness of the first rib waveguide layer that is adjacent to the slab waveguide is thinner than a thickness of the third rib waveguide layer that are sequentially stacked.
Heideman et al. teaches waveguide (302) of phase shifter (122) having core layers (406, 408, 410) are sequentially stacked where a thickness (t1) of the first rib waveguide layer (406) is thinner than a thickness (t3) of the third rib waveguide layer (410)(figs. 1 and 4; col. 8, lines 13-15 and 49-50).
Therefore, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention to have Fujikata et al.’s waveguide layers’ thicknesses as taught by Heideman et al. since such modification is a matter of design choice for propagating received light signal based on its wavelengths and mode-field profile (col. 9, lines 4-9).
Regarding claim 2: Fujikata et al./ Heideman et al. discloses the optical phase shifter of claim 1, wherein, when a reverse voltage is applied to the optical phase shifter (Fig. 11), concentrations of electrons and holes in the second rib waveguide layer (1108) establish a refractive index of the second rib waveguide layer, and a phase of light passing through the second rib waveguide layer (1108) is controlled by the refractive index (col. 2, lines 16-21).
Regarding claim 4: Fujikata et al./ Heideman et al. discloses the optical phase shifter of claim 1, wherein a depletion layer is formed between the first slab region (1130) and the second slab region (1132) and between the second slab region and the first rib waveguide layer, and, when a reverse voltage is applied to the optical phase shifter, an area of the depletion layer is increased (col. 8, lines 52-60).
Regarding claim 5: Fujikata et al./ Heideman et al. discloses the optical phase shifter of claim 1, wherein the first rib waveguide layer, the second rib waveguide layer, and the third rib waveguide layer are doped into the first conductivity type (fig. 11; all three layers 1126, 1108, and 1122 are p-type).
Regarding claim 16: Fujikata et al./ Heideman et al. discloses the optical phase shifter of claim 1, wherein the one side of the first rib waveguide layer (1126 and 1128 combined) overlies the first slab region (1130), and the opposite side of the first rib waveguide layer overlies the second slab region (1132) (fig. 11).
Claim(s) 1 and 10 -14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhou et al. (US 2021/0373363 A1) in view of Heideman et al. (US 9764352 B2).
Regarding claim 1: Zhou et al. discloses an optical phase shifter comprising: a slab waveguide in which a first slab region (430) doped into a first conductivity type (p-doped) and a second slab region (440) doped into a second conductivity type (n-doped) are arranged side by side to form a PN junction; and a rib waveguide (450”) disposed on the slab waveguide, the rib waveguide including a first rib waveguide layer (434) adjacent to the slab waveguide, a second rib waveguide layer (444) stacked on the first rib waveguide layer, a third rib waveguide layer (436) stacked on the second rib waveguide layer, wherein one side of the first rib waveguide layer (434) makes contact with the first slab region (430), and an opposite side of the first rib waveguide layer (434) makes contact with the second slab region (430), wherein the first rib wavequide layer (434) and the third rib waveguide layer (436) include silicon (Si) ([0024]), and wherein the second rib waveguide layer (444) includes silicon-germanium (SiGe) ([0024]).
Zhou et al. is silent with respect to a thickness of the first rib waveguide layer that is adjacent to the slab waveguide is thinner than a thickness of the third rib waveguide layer that are sequentially stacked.
Heideman et al. teaches waveguide (302) of phase shifter (122) having core layers (406, 408, 410) are sequentially stacked where a thickness (t1) of the first rib waveguide layer (406) is thinner than a thickness (t3) of the third rib waveguide layer (410)(figs. 1 and 4; col. 8, lines 13-15 and 49-50).
Therefore, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention to have Zhou et al.’s waveguide layers’ thicknesses as taught by Heideman et al. since such modification is a matter of design choice for propagating received light signal based on its wavelengths and mode-field profile (col. 9, lines 4-9).
Regarding claim 10: Zhou et al./ Heideman et al. discloses the optical phase shifter of claim 1, wherein the rib waveguide further includes: a fourth rib waveguide layer (446) including silicon-germanium (SiGe) ([0024]) and disposed on the third rib waveguide layer (436); and a fifth rib waveguide layer (432) including silicon (Si) ([0024]) and disposed on the fourth rib waveguide layer (layer 432 is disposed on a side surface of layer 436 (fig. 4D)).
Regarding claim 11: Zhou et al. discloses a method for manufacturing an optical phase shifter, the method comprising: preparing a substrate structure in which a base substrate, an insulating layer, and a silicon (Si) layer are sequentially stacked (Fig. 17A);
forming a first empty space in a central portion of the silicon layer by etching the central portion of the silicon layer such that a level of the central portion of the silicon layer is lower than a level of each of both ends of the silicon layer (Fig. 17B; [0111]);
forming a slab waveguide in which a PN junction is formed at a junction between a first slab region (1330) and a second slab region (1340) by doping a first region of the etched silicon layer into a first conductivity type and doping a second region of the etched silicon layer, which is arranged side by side with the first region of the etched silicon layer, into a second conductivity type (Fig. 17C);
depositing a mask in a first empty space formed in a central portion of the slab waveguide; forming a second empty space (1455) between the slab waveguide and the mask by etching the mask to expose a portion of the first region and a portion of the second region (Fig. 18A);
forming a rib waveguide in the second empty space (Fig. 18E), the rib waveguide including a first rib waveguide layer (1432) adjacent to the slab waveguide (1330 and 1340), a second rib waveguide layer (1442) stacked on the first rib waveguide layer, a third rib waveguide layer (1434) stacked on the second rib waveguide layer; and
forming electrodes on the first slab region and the second slab region of the slab waveguide (device has electrodes, see Par. 19),
wherein the first rib waveguide layer and the third rib waveguide layer include silicon (Si), and the second rib waveguide layer includes silicon-germanium (SiGe) (layers can be independently formed of various materials including Si and SiGe, see Par. 24).
Zhou et al. is silent with respect to a thickness of the first rib waveguide layer that is adjacent to the slab waveguide is thinner than a thickness of the third rib waveguide layer that are sequentially stacked.
Heideman et al. teaches waveguide (302) of phase shifter (122) having core layers (406, 408, 410) are sequentially stacked where a thickness (t1) of the first rib waveguide layer (406) is thinner than a thickness (t3) of the third rib waveguide layer (410)(figs. 1 and 4; col. 8, lines 13-15 and 49-50).
Therefore, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention to have Zhou et al.’s waveguide layers’ thicknesses as taught by Heideman et al. since such modification is a matter of design choice for propagating received light signal based on its wavelengths and mode-field profile (col. 9, lines 4-9).
Regarding claim 12: Zhou et al./ Heideman et al. discloses the method of claim 11, wherein forming of the rib waveguide in the second empty space includes:
forming the first rib waveguide layer in the second empty space by growing silicon (Si) from the slab waveguide (rib waveguide layers may be epitaxially grown, see Par. 29);
forming a second rib waveguide layer on the first rib waveguide layer by growing silicon-germanium (Si-Ge) from the first rib waveguide layer (rib waveguide layers may be epitaxially grown, see Par. 29); and
forming a third rib waveguide layer on the second rib waveguide layer by growing silicon (Si) from the second rib waveguide layer (rib waveguide layers may be epitaxially grown, see Par. 29).
Regarding claim 13: Zhou discloses a method for manufacturing an optical phase shifter, the method comprising: preparing a substrate structure in which a base substrate, an insulating layer, and a silicon (Si) layer are sequentially stacked (Fig. 17A);
forming a first empty space in a central portion of the silicon layer by etching the central portion of the silicon layer such that a level of the central portion of the silicon layer is lower than a level of each of both ends of the silicon layer (Fig. 17B);
forming a slab waveguide in which a PN junction is formed at a junction between a first slab region (1330) and a second slab region (1340) by doping a first region of the etched silicon layer into a first conductivity type and doping a second region of the etched silicon layer, which is arranged side by side with the first region of the etched silicon layer, into a second conductivity type (Fig. 17C);
filling a second empty space formed in a central portion of the slab waveguide with a rib waveguide, the rib waveguide including a first rib waveguide layer (1432) adjacent to the slab waveguide (1330 and 1340), a second rib waveguide layer (1442) stacked on the first rib waveguide layer, a third rib waveguide layer (1434) stacked on the second rib waveguide layer, and the first rib waveguide layer (1432), the second rib waveguide layer (1442), and the third rib waveguide layer (1434) are stacked along a surface profile of the slab waveguide;
performing planarization such that a top surface of each of both ends of the slab waveguide and a top surface of the rib waveguide filling the second empty space have a same level by removing the rib waveguide formed on the both ends of the slab waveguide while allowing the rib waveguide filling the second empty space to remain; etching the rib waveguide filling the second empty space to expose a portion (where 1334 deposited) of the first slab region of the slab waveguide and a portion (where 1344 deposited) of the second slab region of the slab waveguide (figs. 17G and 17I); and forming electrodes on the first slab region and the second slab region of the slab waveguide, respectively (device has electrodes, see Par. 19).
Zhou et al. is silent with respect to a thickness of the first rib waveguide layer that is adjacent to the slab waveguide is thinner than a thickness of the third rib waveguide layer that are sequentially stacked.
Heideman et al. teaches waveguide (302) of phase shifter (122) having core layers (406, 408, 410) are sequentially stacked where a thickness (t1) of the first rib waveguide layer (406) is thinner than a thickness (t3) of the third rib waveguide layer (410)(figs. 1 and 4; col. 8, lines 13-15 and 49-50).
Therefore, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention to have Zhou et al.’s waveguide layers’ thicknesses as taught by Heideman et al. since such modification is a matter of design choice for propagating received light signal based on its wavelengths and mode-field profile (col. 9, lines 4-9).
Regarding claim 14: Zhou et al./ Heideman et al. discloses the method of claim 13, wherein the first and third rib waveguide layers include silicon (Si), and the second rib waveguide layer includes silicon-germanium (SiGe) (layers can be independently formed of various materials including Si and SiGe, see Par. 24.
Claim(s) 6-7, 9 and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhou et al. (US 2021/0373363 A1 hereinafter Zhou) in view of Heideman et al. (US 9764352 B2) as discuss above, and further in view of Gunn, III et al. (US 2006/0008223 A1).
Regarding claims 6-7; Zhou et al./ Heideman et al. discloses the optical phase shifter of claim 1 above, but fails to disclose that the first slab region includes the first slab region includes a first-first slab region having a first doping concentration, a first-second slab region that is arranged side-by-side with the first-first slab region and that has a second doping concentration that is lower than the first doping concentration, and a first-third slab region that is arranged side-by-side with the first-second slab region and that has a third doping concentration that is lower than the second doping concentration, wherein the slab waveguide is disposed such that the first-third slab region and the second-third slab region make contact with each other.
Gunn et al. teaches an optical phase shifter having a first slab region (920, Fig. 11) having a first-first slab region (920A, Fig. 11) having a first doping concentration (Par. 74), a first-second slab region (920B, Fig. 11) that is arranged side-by-side with the first-first slab region and that has a second doping concentration that is lower than the first doping concentration (Fig. 12; Par. 74), and a first-third slab region (920C, Fig. 11) that is arranged side-by-side with the first-second slab region and that has a third doping concentration that is lower than the second doping concentration (Fig. 12; Par. 74), wherein the slab waveguide is disposed such that the first-third slab region and the second-third slab region make contact with each other (Fig. 11). Therefore, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention, to have incorporated a stepped arrangement of dopant zones as taught by Gunn et al. within the optical phase shifter disclosed by Zhou et al./ Heideman et al. in order to optimize performance of the phase shifting device.
Regarding claim 9: Zhou et al./ Heideman et al. discloses the optical phase shifter of claim 1 above, but does not explicitly disclose in a first area in which the second slab region and the first rib waveguide layer overlap, the optical phase shifter has a first modulation efficiency and a first optical modulation speed, in a second area in which the second slab region and the first rib waveguide layer overlap, the optical phase shifter has a second modulation efficiency and a second optical modulation speed, the first area is wider than the second area, the first optical modulation efficiency is improved compared to the second optical modulation efficiency, and the first optical modulation speed is reduced compared to the second optical modulation speed.
Gunn et al. teaches in a first area (930D and 930E) in which the second slab region (930) and the first rib waveguide layer overlap, the optical phase shifter has a first modulation efficiency and a first optical modulation speed, in a second area (930F) in which the second slab region and the first rib waveguide layer overlap, the optical phase shifter has a second modulation efficiency and a second optical modulation speed, the first area is wider than the second area (930F) (fig. 11). Since the first area (930D and 930E) has higher doping than the second area (930F) (fig. 12; [0074-0076]), and since increasing the doping level generally enhances the modulation speed and reduced efficiency, the first optical modulation efficiency is improved compared to the second optical modulation efficiency, and the first optical modulation speed is reduced compared to the second optical modulation speed. Accordingly, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention to have Zhou et al./ Heideman et al.’s doping distribution levels as taught by Gunn et al. for intended use to control modulation speed and efficiency as desired (Gunn et al. [0076-0077]).
Regarding claim 15: Zhou et al./ Heideman et al./ Gunn et al. discloses the optical phase shifter of claim 6, wherein the second slab region (930) includes a second-first slab region (930D) having a fourth doping concentration, a second-second slab region (930E) that is arranged side-by-side with the second-first slab region and that has a fifth doping concentration that is lower than the fourth doping concentration, and a second-third slab region (930F) that is arranged side-by-side with the second-second slab region and that has a sixth doping concentration that is lower than the fifth doping concentration (Figs. 11-12; [0074]).
Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhou et al. (US 2021/0373363 A1) in view of Heideman et al. (US 9764352 B2) and Gunn, III et al. (US 2006/0008223 A1) as discuss above, and further in view of Chern (US 2021/0341766 A1).
Regarding claim 8, Zhou/ Heideman / Gunn discloses the optical phase shifter of claim 7.
Zhou/ Heideman / Gunn fails to disclose that a thickness of the first-first slab region is thicker than a thickness of each of the first-second slab region and the first-third slab region, and a thickness of the second-first slab region is thicker than a thickness of each of the second-second slab region and the second-third slab region.
Chern teaches an optical phase shifter (Fig. 17C) where a doped slab region (236 and 238, Fig. 17C) has a width that varies from thicker in the highly doped regions furthest from the central rib waveguide (218, 228, Fig. 17C) to thinner in the lower doped regions closest to the rib waveguide (218, 219). Chern implements this arrangement as a way to optimize performance of the optical phase shifter (Par. 25). Therefore, it would have been obvious to a person having ordinary skill in the art, before the effective filing date of the claimed invention, to have incorporated differential thickness of the slab waveguide as taught by Chern, within the optical phase shifter disclosed by Zhou/ Heideman / Gunn in order to optimize performance of the phase shifting device.
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 nonprovisional extension fee (37 CFR 1.17(a)) 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 mailing date of this final action.
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/UYEN CHAU N LE/Supervisory Patent Examiner, Art Unit 2874