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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on January 12th, 2026 has been entered.
Response to Amendment
Applicant’s amendment filed on January 12th, 2026 has been fully considered and entered. The amendments acknowledged: Claims 1, 8, and 15 have been amended to clarify the claimed subject matter. These claims introduce no new matter.
Response to Arguments
Applicant’s arguments filed January 12th, 2026 have been fully considered but they are not persuasive.
Applicant states that “The combination of Brouckaert and Anderson does not teach, suggest, or otherwise render obvious "an optical mode mux coupled to a second end of the
asymmetrically tapered waveguide, wherein the optical mode mux comprises a filtering
section configured to filter one or more input modes of the optical signal and wherein the filtering section is positioned downstream from the asymmetrically tapered waveguide," as recited in Claim 1, and similarly in Claims 8 and 15.”
The examiner disagrees that the optical mode mux is not taught as claimed by Brouckaert et al., which discloses a region that is structurally and mechanically identical to the claimed multiplexing region, wherein the input modes are filtered and passed along two separate branches, downstream from the asymmetrically tapered waveguide (MMI section 10 is downstream of an asymmetrically tapered waveguide, and is designed to permit one mode along one branch, and another mode along another branch, see paragraphs 7, 9, 30, and 39-43).
As a result, the ‘filtering section’ is taught by Brouckaert et al. Though not used for this particular rejection, it is equally taught by Anderson et al., which is part of the obviousness combination; Anderson teaches an identical optical splitting structure to the claimed limitation, downstream of an asymmetrical taper (Figures 3 and 4 show this best).
The rejection under 35 USC 103 under Brouckaert et al. in view of Anderson et al. is therefore maintained.
Applicant argues that claims 2-5, 9-12, 16-20 and claims 6 and 13 are nonobvious as a result of the base claims 1, 8, and 15 being nonobvious.
The examiner respectfully disagrees.
The response to applicant arguments above and rejections detail why the base claims are nonobvious. Therefore, the remaining pending claims cannot be nonobvious under In re Fine F.2d 1071, 5 USPQ2d 1596 (Fed. Cir. 1988).
Claim Rejections - 35 USC § 103
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 (i.e., changing from AIA to pre-AIA ) 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.
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, 5-8, and 12-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Brouckaert et al. (EP 2 924 482 A1) in view of Anderson et al. (US 20140270620 A1).
Regarding claim 1;
Brouckaert et al. discloses an optical splitter (see Figures 9 and 10), comprising:
an asymmetrically tapered waveguide (asymmetric section in Figures 9 and 10; waveguide 2 with silicon layer 4; see Figures 1-8 and 10) comprising a first end configured to receive an optical signal (TM, TE) comprising a single mode, wherein the single mode comprises a fundamental mode (TE0, TM0); and
an optical mode mux (MMI section; see 10) coupled to a second end of the asymmetrically tapered waveguide (2, 4),
wherein the optical mode mux comprises a filtering section configured to filter one or more input modes of the optical signal and wherein the filtering section is positioned downstream from the asymmetrically tapered waveguide (MMI section 10 is downstream of an asymmetrically tapered waveguide and is designed to permit one mode along one branch, and another mode along another branch, see paragraphs 7, 9, 30, and 39-43),
wherein the asymmetrically tapered waveguide (2, 4; see paragraphs 7, 9, 30, and 39-43) is configured to convert a first portion of an optical signal from the fundamental mode (TM0 or TE0) to a different order mode (TE1) while a second portion of the optical signal (TE0) remains in the fundamental mode (TE0),
wherein the first portion (TM0/TE1) of the optical signal is transmitted in the first branch of the optical mode mux (MMI) and is converted back into the fundamental mode (TE0; see Figure 10 and paragraph 43) before being output by the optical mode mux (MMI) and the second portion of the optical signal (TE0) is transmitted in the second branch of the optical mode mux (MMI).
Brouckaert does not disclose that the asymmetrically tapered waveguide contains a first taper section associated with a first branch of the optical mode mux and a second taper section associated with a second branch of the optical mode mux.
Anderson et al. teaches an optical waveguide structure (Figure 3) that contains a first taper section (first tapering portion 347) associated with a first branch (389a) of an optical mode mux (asymmetric Y-splitter 343 is a mux) and a second taper section (349) associated with a second branch (389b) of an optical mode mux.
Before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to modify the invention of Brouckaert et al. by replacing the splitter (i.e. Figure 10, “splitter + phase section + MMI” contains a splitter between the two branches and the waveguide) with the splitter of Anderson et al. at the second end of the asymmetrically tapered waveguide, and attaching it to the two branches. This may be accomplished using methods known to the art (routine machining, placement of parts), and would predictably result in a splitter with two tapered regions which couple to two branches, and which are therefore capable of selectively propagating specific modes of light, and converting TE and TM polarizations into separate TE modes efficiently.
Regarding claim 5,
Brouckaert et al. in view Anderson et al. discloses the optical splitter of claim 1, wherein the second branch of the optical mode mux is physically coupled to the second end of the asymmetrically tapered waveguide, wherein the first branch is spaced apart from the second branch by a gap (Figure 9 shows this explicitly).
Regarding claim 6,
Brouckaert et al. in view Anderson et al. teaches the optical splitter of claim 5.
Brouckaert et al. does not teach that the first branch is also not directly connected to the asymmetrically tapered waveguide.
Anderson et al. teaches an optical splitter wherein the two branches are physically coupled but spaced apart by a gap, and also where the first branch is not directly connected to either the second branch or the waveguide (Figure 2).
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to modify the invention disclosed in the rejection of claim 5 above, under the teachings of Anderson et al., to space apart the first branch from both the second branch and the waveguide. This could be accomplished using routine placement techniques known to the art, and would predictably result in a waveguide wherein the crosstalk between optical channels is reduced, leading to better signal integrity and lower loss.
Regarding claim 7,
Brouckaert et al. in view of Anderson et al. discloses the optical splitter of claim 1 (Figure 9, Figure 10), wherein the different order mode is a first order mode (TE1).
Regarding claim 8;
Brouckaert et al. discloses a photonic chip (paragraph 1), comprising:
a single mode waveguide (TM0/TE0, paragraph 7);
an asymmetrically tapered waveguide (asymmetric section in Figures 9 and 10; waveguide 2 with silicon layer 4; see Figures 1-8 and 10) comprising a first end configured to receive an optical signal (TM, TE) in a single mode, wherein the single mode (i.e. a single spatial mode) comprises a fundamental mode (at least one of TE0, TM0) from the single mode waveguide; and
an optical mode mux (MMI section; see 10) coupled to a second end of the asymmetrically tapered waveguide (2, 4),
wherein the optical mode mux comprises a filtering section configured to filter one or more input modes of the optical signal and wherein the filtering section is positioned downstream from the asymmetrically tapered waveguide (MMI section 10 is downstream of an asymmetrically tapered waveguide and is designed to permit one mode along one branch, and another mode along another branch, see paragraphs 7, 9, 30, and 39-43),
wherein the asymmetrically tapered waveguide (2, 4; see paragraphs 7, 9, 30, and 39-43) is configured to convert a first portion of an optical signal from the fundamental mode (TM0) to a different order mode (TE1) while a second portion of the optical signal (TE0) remains in the fundamental mode (TE0),
wherein the first portion (TM0/TE1) of the optical signal is transmitted in the first branch of the optical mode mux (MMI) and is converted back into the fundamental mode (TE0; see Figure 10 and paragraph 43) before being output by the optical mode mux (MMI) and the second portion of the optical signal (TE0) is transmitted in the second branch of the optical mode mux (MMI).
Brouckaert et al. does not disclose that the asymmetrically tapered waveguide contains a first taper section associated with a first branch of the optical mode mux and a second taper section associated with a second branch of the optical mode mux.
Anderson et al. teaches an optical waveguide structure (Figure 3) that contains a first taper section (first tapering portion 347) associated with a first branch (389a) of an optical mode mux (asymmetric Y-splitter 343 is a mux in practice) and a second taper section (349) associated with a second branch (389b) of an optical mode mux.
Before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to modify the invention of Brouckaert et al. by replacing the splitter (i.e. Figure 10, “splitter + phase section + MMI” contains a splitter between the two branches and the waveguide) with the splitter of Anderson et al. at the second end of the asymmetrically tapered waveguide, and attaching it to the two branches. This may be accomplished using methods known to the art (routine machining, placement of parts), and would predictably result in a splitter with two tapered regions which couple to two branches, and which are therefore capable of selectively propagating specific modes of light, and converting TE and TM polarizations into separate TE modes efficiently.
Regarding claim 12,
Brouckaert et al. in view Anderson et al. discloses the optical splitter of claim 8, wherein the second branch of the optical mode mux is physically coupled to the second end of the asymmetrically tapered waveguide, wherein the first branch is spaced apart from the second branch by a gap (Figure 9 shows this explicitly).
Regarding claim 13,
Brouckaert et al. in view Anderson et al. teaches the optical splitter of claim 12.
Brouckaert et al. does not teach that the first branch is also not directly connected to the asymmetrically tapered waveguide.
Anderson et al. teaches an optical splitter wherein the two branches are physically coupled but spaced apart by a gap, and also where the first branch is not directly connected to either the second branch or the waveguide (Figure 2).
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to modify the invention disclosed in the rejection of claim 12 above, under the teachings of Anderson et al., to space apart the first branch from both the second branch and the waveguide. This could be accomplished using routine placement techniques known to the art, and would predictably result in a waveguide wherein the crosstalk between optical channels is reduced, leading to better signal integrity and lower loss.
Regarding claim 14,
Brouckaert et al. in view of Anderson et al. discloses the photonic chip of claim 8 (Figure 9, Figure 10), wherein the different order mode is a first order mode (TE1).
Regarding claim 15;
Brouckaert et al. discloses a method, comprising:
Receiving an optical signal having a single mode (TM0/TE0, paragraph 7);
converting a portion of the optical signal from a fundamental mode (TM0) to a different order mode (TE1)
transferring the portion of the optical signal that is in the different order mode (TE1) into a first branch of an optical mode mux (MMI) and converting the portion of the optical signal back into the fundamental mode (TE0; see Figure 10 and paragraph 43); and
transmitting a remaining portion of the optical signal (TE0) in a second branch of the optical mode mux (MMI).
wherein the optical mode mux comprises a filtering section configured to filter one or more input modes of the optical signal and wherein the filtering section is positioned downstream from the asymmetrically tapered waveguide (MMI section 10 is downstream of an asymmetrically tapered waveguide and is designed to permit one mode along one branch, and another mode along another branch, see paragraphs 7, 9, 30, and 39-43),
Brouckaert et al. does not disclose that the first/second branches of the optical mode mux contain a first/second taper section, respectively.
Anderson et al. teaches an optical waveguide structure (Figure 3) which contains an optical mode mux (asymmetric Y-splitter 343 functions as a mux for right-to-left signal propagation) with two branches (389a/b), wherein the first branch of the optical mode mux (389a) contains a first taper section (347) and the second branch of the optical mode mux (389b) contains a second taper section (349).
Before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to modify the method taught in Brouckaert et al. with the method taught in Anderson et al., by utilizing a mux with two branches which are tapered. This could be accomplished using components and methods known to the art, and would predictably provide the benefit of a mux which is capable of transmitting multimode signals with mode field matching, reduced diffraction, and minimal loss.
Claim(s) 2-4, 9-11, and 16-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Brouckaert et al. (EP 2924482 A1) in view of Anderson et al. (US 20140270620 A1), and further in view of Park et al. (WO 2009/145383 A1).
Regarding claim 2,
Brouckaert et al. in view of Anderson et al. teaches the optical splitter of claim 1,
Brouckaert et al. does not teach an optical splitter wherein a center axis of the first end of the asymmetrically tapered waveguide is misaligned with a center axis of the second end of the asymmetrically tapered waveguide.
Park et al. teaches an optical splitter (see Figure 1),
wherein a center axis (dashed line by ∠1 ) of the first end of the asymmetrically tapered waveguide (left vertical line coming down from L1) is misaligned with a center axis (compare the centers of W2 to W1) of the second end of the asymmetrically tapered waveguide (right vertical line coming down from L1).
Before the effective filing date of the claimed invention, a person of ordinary skill in the art would have found it obvious to alter the geometry of the asymmetrically tapered waveguide in the device described in the rejection of claim 1 above, such that the first end is misaligned with the second end, as seen in Park et al. This would predictably result in a device where different modes may propagate along different branches connected to a mux with high efficiency and low loss.
Regarding claim 3,
Brouckaert et al. in view of Anderson et al. and Park et al. teaches the optical splitter of claim 2.
Brouckaert et al. further teaches that the signal is converted into a different order mode after receiving an input signal and passing it through an optical splitter and waveguide (see top branch of Fig 9, Fig 10. TM →TE).
Brouckaert et al. does not teach that there is a misalignment between first and second center axes.
Park et al. teaches that the misalignment between the center axes of the first and second (Figure 2, W1 and W2) ends affects an amount of power of the optical signal that is transmitted on the first branch of the optical mode mux (Figs. 11-18).
Before the effective filing date of the claimed invention, a person of ordinary skill in the art would have found it obvious to utilize the teachings of Park et al. to modify the device described in the rejection of claim 2 above, using routine placement techniques known to the art. This would predictably convert the fundamental mode into a different order mode, and provide control over the power of the optical signal transmitted on the first branch of the optical mode mux.
Regarding claim 4,
Brouckaert et al. in view Anderson et al. and Park et al. teaches the optical splitter of claim 2,
Brouckaert et al. does not teach that the misalignment between center axes of the first and second ends sets a power splitting ratio between outputs of the first and second branches in the optical mode mux.
Park et al. teaches an optical splitter, wherein the misalignment between the center axes of the first and second ends sets a power splitting ratio between outputs of the first and second branches in the optical mode mux (paragraph 28; Figs 11-18; the “split ratio” is controlled by the misalignment between the centers of W1 and W2).
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to misalign the central axes of the first and second ends of the optical splitter in the device described in the rejection of claim 2 above, under the teachings of Park et al. using methods known in the art (routine placement techniques, machining design judgment). This would predictably allow one to set the power splitting ratio between the outputs of the two branches of the optical mode mux.
Regarding claim 9,
Brouckaert et al. in view of Anderson et al. teaches the photonic chip of claim 8,
Brouckaert et al. does not teach that a center axis of the first end of the asymmetrically tapered waveguide is misaligned with a center axis of the second end of the asymmetrically tapered waveguide.
Park et al. teach a photonic chip (see Figure 1),
wherein a center axis (dashed line by ∠1 ) of the first end of the asymmetrically tapered waveguide (left vertical line coming down from L1) is misaligned with a center axis (compare the centers of W2 to W1) of the second end of the asymmetrically tapered waveguide (right vertical line coming down from L1).
Before the effective filing date of the claimed invention, a person of ordinary skill in the art would have found it obvious to alter the geometry of the asymmetrically tapered waveguide in the device described by the rejection of claim 8 above, such that the first end is misaligned with the second end, as seen in Park et al. This would predictably allow one to control the power of the output signal without altering the function of the claimed invention.
Regarding claim 10,
Brouckaert et al. in view of Anderson et al. and Park et al. teaches the photonic chip of claim 9, wherein:
the signal is converted into a different order mode after receiving an input signal and passing it through an optical splitter and waveguide (see top branch of Fig 9, Fig 10. TM →TE).
Brouckaert et al. does not teach a misalignment between the first and second axes.
Park et al. teaches that a misalignment between the center axes of the first and second (Figure 2, W1 and W2) ends affects an amount of power of the optical signal that is transmitted on the first branch of the optical mode mux (Figs. 11-18).
Before the effective filing date of the claimed invention, a person of ordinary skill in the art would have found it obvious to modify the waveguide in the device described by the rejection of claim 9 under the teachings of Park et al. to have a misalignment between the center axes of the first and second ends of the waveguide, using methods known in the art. This would predictably convert the fundamental mode into a different order mode, and naturally affect the amount of power of the optical signal transmitted on the first branch of the optical mode mux.
Regarding claim 11,
Brouckaert et al. in view of Anderson et al. and Park et al. teaches the photonic chip of claim 9.
Brouckaert et al. does not teach that the misalignment between center axes of the first and second ends sets a power splitting ratio between outputs of the first and second branches in the optical mode mux.
Park et al. teaches an optical splitter, wherein the misalignment between the center axes of the first and second ends sets a power splitting ratio between outputs of the first and second branches in the optical mode mux (paragraph 28; Figs 11-18; the “split ratio” is controlled by the misalignment between the centers of W1 and W2).
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to misalign the central axes of the first and second ends of the optical splitter in the device described in the rejection of claim 9 above, under the teachings of Park et al. using methods known in the art (routine placement techniques, machining design judgment). This would predictably allow one to set the power splitting ratio between the outputs of the two branches of the optical mode mux.
Regarding claim 16:
Brouckaert et al. in view of Anderson et al. discloses the method of claim 15,
Brouckaert et al. does not disclose converting a portion of the optical signal from a fundamental mode to a different order mode is performed using an asymmetric taper.
Park et al. teaches that converting a portion of the optical signal from a fundamental mode to a different order mode may be performed using an asymmetric taper (Fig 2., 11, 12, 13).
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to modify the device described in the rejection of claim 15 above, by introducing the tapering taught in Park et al. and modifying the geometry of the waveguide. This would have the predictable effect of converting a portion of the optical signal into a different order mode without modifying the function of the claimed invention.
Regarding claim 17:
Brouckaert et al. in view of Anderson et al. and Park et al. discloses the method of claim 16,
Brouckaert et al. does not teach that the center axis of a first end of the asymmetric taper is misaligned with a center axis of a second end of the asymmetric taper.
Park et al. teaches a method, wherein a center axis of a first end of the asymmetric taper is misaligned with a center axis of a second end of the asymmetric taper (Park et al. Fig 2., 11, 12, 13)
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to misalign the central axes of the first and second ends of the optical splitter in the device described in the rejection of claim 16 above, under the teachings of Park et al. using methods known in the art (routine placement techniques, machining design judgment). This would predictably allow one to set the power splitting ratio between the outputs of the two branches of the optical mode mux.
Regarding claim 18:
Brouckaert et al. in view of Anderson et al. and Park et al. discloses the method of claim 17,
Brouckaert et al. does not teach that the misalignment between the center axes of the first and second ends affects an amount of power of the optical signal that is converted into the different order mode and transmitted on the first branch of the optical mode mux.
Park et al. teaches a method, wherein the misalignment between the center axes of the first and second ends (compare the centers of W2 to W1) affects an amount of power of the optical signal that is converted into the different order mode and transmitted on the first branch of the optical mode mux (Figs 11-18 depict the different power splitting ratios that result from varying the misalignment).
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to modify the device described in the rejection of claim 17 above, to utilize the offset of central axes of the first and second ends in Park et al. to affect the amount of power transmitted along the first branch of the optical mode mux. The power transmitted would predictably be controlled by this offset without changing the function of the claimed invention.
Regarding claim 19:
Brouckaert et al. in view of Anderson et al. discloses the method of claim 15,
Brouckaert et al. does not disclose that the power ratio between an output of the first branch and an output of the second branch is less than 15/85.
Park et al. discloses a power ratio between an output of the first branch and an output of the second branch is less than 15/85 (Figure 17 depicts 10/90).
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to incorporate the power ratio control method taught in Park et al. in the method described in the rejection of claim 15 above using methods known in the art. This would have predictably led to a power splitting ratio less than 15/85.
Regarding claim 20:
Brouckaert et al. in view of Anderson et al. and Park et al. discloses the method of claim 19.
Brouckaert et al. does not disclose that the power ratio between an output of the first branch and an output of the second branch is less than 10/90.
Park et al. discloses a power ratio between an output of the first branch and an output of the second branch is less than 10/90 (Figure 18 depicts 1/99).
Before the effective filing date of the present invention, a person of ordinary skill in the art would have found it obvious to incorporate the power ratio control method taught in Park et al. in the method described in the rejection of claim 19 above using methods known in the art. This would have predictably led to a power splitting ratio less than 10/90.
Conclusion
THIS ACTION IS MADE FINAL. 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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/PREET B PATEL/Examiner, Art Unit 2874 /THOMAS A HOLLWEG/Supervisory Patent Examiner, Art Unit 2874