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 8/29/25 are acknowledged. Claims 1 – 5, 7, 8, 10, 11, and 16 have been amended, and claims 6, 9, 14, and 19 canceled. Claims 1 – 5, 7, 8, 10 – 13, 15 – 18, and 20 are pending.
Response to Amendments / Arguments
Applicant's amendments have obviated the previously-raised rejections of claims 11 and 16 under 35 USC 102 and necessitated new rejections under 35 USC 103, as detailed below.
Applicant's arguments regarding the amended claims versus the previously-raised rejections under 35 USC 103(a) based on the Sun – Asl combination have been fully considered but they are not persuasive. Furthermore, the arguments are in part moot in view of the new grounds of rejections, as necessitated by the Applicant’s amendments.
Amended claims 1, 11, and 16:
Applicant argues (last para. on p. 2 of the Remarks) that the range in Asl is open-ended without any particular upper range limit stated/exemplified. Applicant also points out that a length of 25 mm is longer than the wavelength of a 40 GHz RF signal and “That shift from a short, sub-wavelength segment to a multi-wavelength transmission line changes the problem fundamentally: distributed effects dominate; small impedance errors create large reflections and standing waves; phase accumulation, loss, and dispersion become significant; and the line itself behaves as an impedance transformer/resonant structure” (1st para. on p. 3).
The Examiner notes the following:
(i) Impedance matching, reflections, etc. are of consideration at almost any length of the transmission line. Furthermore, the impact of reflections at the distal end of the transmission line (at the ring resonator) decreases at longer lengths of the transmission line due to higher attenuation of reflected waves over a longer propagation distance. Hence, if the transmission line is optimized for lower enough reflection at a shorter length, re-optimization of the transmission line at a longer length for the same level of reflection may not be any more challenging.
(ii) While Applicant argues about a potential adverse impact of impedance mismatch and reflections, Applicant’s argument is for the most part moot, at least because the present form of claims neither provides/quantifies any acceptable level of reflections (or phase accumulations, etc) nor defines any particular structural features of the claimed transmission line that mitigate such adverse effects. Instead, the claims recite only a fairly generic transmission line.
Applicant asserts that “It is not a routine range optimization, but a different class of interconnect problem” (bid), but does not detail how a transmission line can be optimized for a range of lengths. Such optimization can be performed using a wide variety of criteria and trade-offs and they are not presented by Applicant for the claimed transmission line. Hence, Applicant’s argument cuts both ways.
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 – 4, 7, 8, 11 – 13, 15 – 18, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over “A 128 Gb/s PAM4 Silicon Microring Modulator With Integrated Thermo-Optic Resonance Tuning” by Sun et al, JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 37, NO. 1, pp. 110 – 115, 2019 (hereinafter Sun) in view of Asl et al (US 2020/0371385 A1).
Regarding claim 1, Sun describes (Figs. 1 – 3; Abstract; Section II) a photonic integrated circuit (PIC) die comprising (see annotated Figs. 1a and 1c below):
a waveguide (“Bus Waveguide”);
a microresonator (micro-ring modulator “MRM”) coupled to the waveguide (to couple light in and out of the MRM, as shown in Fig. 1a);
a first bias electrode (comprising the left metal electrode (in gold) over the left n-doped region (in red)) and a second bias electrode (comprising the right metal electrode (in gold) over the right n-doped region (in red)),
wherein the first (left) bias electrode and the second (right) bias electrode apply an electric field across a region (of a PN junction) of the microresonator when a voltage is applied across the first bias electrode and the second bias electrode (Fig. 2a; 1st and 2nd para. of Section II);
a first contact pad (the left modulator pad in Fig. 1c) connected to the first (left) bias electrode;
a second contact pad (the right modulator pad in Fig. 1c) connected to the second bias electrode.
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Annotated Figs. 1a and 1c of Sun.
Sun uses an RF cable to apply a modulating RF voltage and an external bias-tee to apply the bias voltage, considers a bandwidth limitation caused by them (para. bridging pp. 112 – 113), but does not teach a bias-tee comprised in a termination circuit that is integrated with the PIC die. Furthermore, Sun does not teach a termination circuit integrated with the microresonator. However, Asl discloses (Figs. 1 – 3; Abstract; para. 0020 – 0039) a system 150 having essential features similar to those in Sun and comprising (with reference to the lower portion of Fig. 1):
a photonic integrated circuit (PIC) die 158 comprising a microresonator modulator (MRM) 160 (“the PIC 158 without introducing significant complexity by introducing a termination circuit 159 coupled with the MRM 160 within the PIC 158” at para. 0025);
a driver 156 to drive the microresonator modulator 160 (para. 0025); and
a transmission line 164 (identified as “Transmission Line” in Fig. 2) connecting the driver 156 to the microresonator modulator 160 (as seen in Fig. 2; “a second channel 164 electrically couples the driver 156 with the PIC 158” at para. 0025; also para. 0026).
Asl recognizes a bandwidth limitation caused by high RF reflection in the absence of a termination circuit for the microresonator modulator (“significant portion of the RF electrical signals driving MRMs are reflected back towards the source during E/O conversion” at para. 0022) and proposes a solution in the form of a termination circuit 159 that is integrated with the PIC die (“With this embodiment, reflections from the MRM 160 are significantly reduced by the presence of the termination circuit 159” at para. 0026). Furthermore, the termination circuit 159 comprises a bias tee 270 that is configured to apply a bias voltage to the micro-ring resonator 160 and to terminate (RF) signals on the transmission line (“The MRM bias may be provided by the termination 159, as shown in FIG. 2 where termination circuits 250 and 270 are given as two examples” at para. 0026, emphasis added).
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 PIC die in Sun can be modified, in accordance with the teachings of Asl, to include a termination circuit that is integrated with the PIC die, wherein the termination circuit comprises a bias tee that is configured to apply a bias voltage to the micro-ring resonator and to terminate (RF) signals on the transmission line. The termination circuit has the benefit of reducing (undesired) RF reflections from the micro-ring resonator (para. 0026 of Asl). Furthermore, the termination circuit integrates a bias tee and replaces an external bias tee in Sun with an additional advantage of a compact and mechanically rugged arrangement.
The Sun – Asl combination considers that each bias electrode is terminated a corresponding resistor (resistor R in the termination circuit 270 in Fig. 2 of Asl), so that the PIC die further comprises:
a first resistor connected to the first (left) bias electrode (“The termination impedance, Zterm, is connected to the RF pads” at para. 0028 of Asl) and a third contact pad (for connecting to a following capacitor C, as shown in the termination circuit 270 in Fig. 2 of Asl); and
a second resistor connected to the second (right) bias electrode and a fourth contact pad (for connecting to a following capacitor C, as shown in the termination circuit 270 in Fig. 2 of Asl).
Further, Asl teaches that the driver 156 is to send radiofrequency signals on the transmission line 164 at a frequency of at least 40 GHz (as shown in Fig. 3; “The 3-dB bandwidth of the transmitter improves from 24 GHz to 60 GHz with the termination circuitry due to reduced capacitive impact from the MRM” para. 0035).
Asl teaches that the transmission line 164 is longer than 1 mm (“The second channel 164 may be greater than 1 mm” at para. 0025; also para. 0052 and 0064; claim 3) and, hence, renders obvious a range that at least overlaps with the recited range so that a prima facie case of obviousness exists (MPEP 2144.05). See also a detailed commentary under the Section “Response to Amendments/ Arguments” above.
In light of the foregoing analysis, the Sun – Asl combination teaches expressly or renders obvious all of the recited limitations.
Alternative or additionally, the general structure of the micro-ring resonator in Asl can be modified according to the details provided by Sun (a bus waveguide, two bias electrodes, etc) with the Asl – Sun combination providing an alternative ground of rejections.
As an aside and relevant comments for the other claims, it is noted that Asl recognizes the same problem (high RF reflections; para. 0022) and uses the same solution (the termination circuit 159 which reduces RF reflections; para. 0026) to address the problem as those described by the instant application (para. 0017, 0018, 0060 and 0061 of the instant specification).
Regarding claim 11, the teachings of Sun and Asl combine (see the arguments and motivation for combining, as provided above for claim 1) to teach expressly or render obvious all of the recited limitations, as detailed above for claim 1. Specifically, the Sun – Asl combination considers (Figs. 1 – 3; Abstract; para. 0020 – 0039 of Asl) a system 150 comprising (with reference to the lower portion of Fig. 1):
a photonic integrated circuit (PIC) die 158 comprising a microresonator modulator (MRM) 160 (“the PIC 158 without introducing significant complexity by introducing a termination circuit 159 coupled with the MRM 160 within the PIC 158” at para. 0025);
a driver 156 to drive the microresonator modulator 160 (para. 0025); and
a transmission line 164 (identified as “Transmission Line” in Fig. 2) connecting the driver 156 to the microresonator modulator 160 (as seen in Fig. 2; “a second channel 164 electrically couples the driver 156 with the PIC 158” at para. 0025; also para. 0026),
wherein the PIC die 158 comprises at least one resistor R (comprised in the termination circuit 159, as shown in Fig. 2 for both implementations 250,270 of the termination circuit 159) to terminate signals from the transmission line 164 (“Transmitter 150 illustrates an embodiment that allows independent design of the driver 156 and the PIC 158 without introducing significant complexity by introducing a termination circuit 159 coupled with the MRM 160 within the PIC 158” at para. 0025).
The Sun – Asl combination or renders obvious that the transmission line can be at least 25 millimeters long, wherein the driver is to send radiofrequency signals on the transmission line at a frequency of at least 40 gigahertz (as detailed above for claim 1).
Regarding claim 16, the teachings of Sun and Asl combine (see the arguments and motivation for combining, as provided above for claim 1) to teach expressly or render obvious all of the recited limitations, as detailed above for claim 1. Specifically, the Sun – Asl combination considers (Figs. 1 – 3; Abstract; para. 0020 – 0039 of Asl) a system 150 comprising (with reference to the lower portion of Fig. 1):
a photonic integrated circuit (PIC) die 158 comprising a microresonator modulator (MRM) 160 (“the PIC 158 without introducing significant complexity by introducing a termination circuit 159 coupled with the MRM 160 within the PIC 158” at para. 0025);
a driver 156 to drive the microresonator modulator 160 (para. 0025); and
a transmission line 164 (identified as “Transmission Line” in Fig. 2) connecting the driver 156 to the microresonator modulator 160 (as seen in Fig. 2; “a second channel 164 electrically couples the driver 156 with the PIC 158” at para. 0025; also para. 0026),
wherein the PIC die 158 comprises a bias tee 270 (comprised in the termination circuit 159, as detailed in Fig. 2 for the termination circuit 270), wherein the transmission line 164 (identified as “Transmission Line” in Fig. 2) is connected to one (left) input of the bias tee 270 (as shown in Fig. 2), wherein a voltage source Vbias is connected to a second (right) input of the bias tee 270, and wherein the bias tee 270 is to terminate (RF) signals on the transmission line (“The MRM bias may be provided by the termination 159, as shown in FIG. 2 where termination circuits 250 and 270 are given as two examples” at para. 0026, emphasis added).
The Sun – Asl combination or renders obvious that the transmission line can be at least 25 millimeters long, wherein the driver is to send radiofrequency signals on the transmission line at a frequency of at least 40 gigahertz (as detailed above for claim 1).
Regarding claims 2, 12, and 17, Asl teaches an embodiment (shown in the lower portion of Fig. 1) wherein the at least one resistor R (comprised in the termination circuit 159, as shown in Fig. 2 for both implementations 250,270 of the termination circuit 159) is integrated into the PIC die 158 (as shown in the lower portion of Fig. 1; “by introducing a termination circuit 159 coupled with the MRM 160 within the PIC 158” at para. 0025; “In some embodiments, the termination circuit 159 and the MRM 160 may be located within a PIC 158 as shown with respect to FIG. 1” at para. 0039, emphasis added). Hence, Asl generally renders obvious that the at least one resistor R of the termination circuit 159 can be fabricated during the fabrication of the PIC die 158 and be monolithically integrated into it.
Furthermore, the Examiner took official notice in the Office Action of 5/29/25 that electrical components monolithically integrated in PIC dies were well known in the art. Since Applicant has not traversed the official notice, the fact of common knowledge has become applicant admitted prior art. Such an arrangement would be obvious to a person of ordinary skill in the art and has the benefits of increased integrated density, smaller footprint and improved mechanical ruggedness.
Regarding claim 3, the Sun – Asl combination considers that the contemplated PIC die further comprises:
a first capacitor (for connecting to a capacitor C connected to the first resistor R, as shown in the termination circuit 270 in Fig. 2 of Asl) connected across the third contact pad and a fifth contact pad; and
a second capacitor (for connecting to a capacitor C connected to the second resistor R, as shown in the termination circuit 270 in Fig. 2 of Asl) connected across the fourth contact pad and a sixth contact pad.
Regarding claim 4, the Examiner took official notice in the Office Action of 5/29/25 that MIM-type capacitors were well known in the art. Since Applicant has not traversed the official notice, the fact of common knowledge has become applicant admitted prior art. MIM-type capacitors would be an obvious design choice to a person of ordinary skill in the art in order to implement a pair of capacitors in the termination circuit that is monolithically integrated in the PIC die. Such MIM capacitors can be routinely fabricated using conventional CMOS techniques at low cost and high yields.
Regarding claim 7, the Sun – Asl combination considers that the driver 156 is to transmit radiofrequency (RF) signals (up to at least 60 GHz; Fig. 3; para. 0035 of Asl) on the transmission line 164, wherein the RF signals cause the microresonator to modulate an amplitude of light in the (bus) waveguide (an amplitude frequency response is shown in Fig. 3b of Sun and as a response 300b in Fig. 3 of Asl).
Regarding claim 8, the Sun – Asl combination renders obvious that the first bias electrode and the second bias electrode can receive respective bias voltages from a same/shared voltage source or separate bias voltage sources (set at either different voltages or a same voltage (for redundancy purposes, in case one of the source fails)), as a matter of suitable/workable choices, because the total biasing is the sum of the phase biasing contributions provided by the first bias electrode and the second bias electrode. If separate bias voltage sources are used, a first voltage source connected to the third contact pad; and a second voltage source connected to the fourth contact pad, wherein the first voltage source and the second voltage source are to provide a DC bias to the microresonator.
Regarding claims 13 and 18, the Asl – Sun combination (detailed above for claim 1) teaches expressly or renders obvious all of the recited limitations, as explained above for claim 8.
Regarding claims 15 and 20, the Asl – Sun combination (detailed above for claim 1) teaches expressly or renders obvious all of the recited limitations, as explained above for claim 7.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Sun in view of Asl, and further in view of Basak et al (US 2023/0205043 A1).
Regarding claim 5, the Sun – Asl combination considers that the driver 156 is electrically connected to the PIC die 158 via a separate die/substrate 152 (the lower portion of Fig. 1 and para. 0025 of Asl). While such connections are commonly implemented as solder bumps, the Sun – Asl combination does not expressly name them. However, Basak discloses (Fig. 6B; Abstract; para. 0049) a driver 2 that is electrically connected to a PIC die 4 via a separate die/substrate 3, wherein the electrical connection is implemented by using solder bumps (“The flip-chip electrical connections 51, 52 and 53 may be between facing surfaces of the electronic driver 2 and the multi-layer interconnect substrate 3 and between facing surfaces of multi-layer interconnect substrate 3 and the PIC 4, e.g. solder bumps and pads provided along the top of the multi-layer interconnect 3 or the bottom on the cavities 47 and 48, if provided” at para. 0049).
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 contact pad, the second contact pad, the third contact pad, and the fourth contact pad which connect to a separate die, as contemplated by the Sun – Asl combination, can be implemented as solder bumps which are a suitable/workable design choice that is expressly taught by Basak and has the benefit of providing multiple electrical connections in a single step of flip-chip bonding (para. 0046 and 0049 of Basak).
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Sun in view of Asl, and further in view of “Reconfigurable electro-optical directed-logic circuit using carrier-depletion micro-ring resonators” by Qiu et al, OPTICS LETTERS, Vol. 39, No. 24, pp. 6767 – 6770, 2014 (hereinafter Qiu).
Regarding claim 10, the Sun – Asl combination does not teach that the PIC can be mounted on a circuit board. However, Qiu describes (Fig. 1 and its caption; 3rd para. on p. 6767) a PIC die with a micro-ring resonator, wherein the PIC can be mounted on a printed circuit board (PCB) and wire-bonded to its electrical conductors/traces.
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 PIC of the Sun – Asl combination can be mounted on a printed circuit board (PCB) and wire-bonded to its electrical conductors/traces, as a design choice expressly taught by Qiu and provides an interface board (3rd para. on p. 6767 of Qiu) and connections to components outside the PIC die.
The Sun – Asl – Qui combination considers that the contemplated system further comprises:
a circuit board (PCB in Qui), wherein the PIC die is mounted on the circuit board (as in Fig. 1 of Qui), and at least four wire bonds to connect two RF pads and two heater pads (as shown in Fig. 1c of Sun) to four corresponding traces on the circuit board (a pair of traces for RF connections and a pair of traces for providing a voltage/current from a source for the heater that tunes the micro-ring resonator, as in Sun and Qui).
The four corresponding traces on the circuit board comprise:
a first wire bond connecting the first contact pad to a first trace on the circuit board;
a second wire bond connecting the second contact pad to a second trace on the circuit board;
a third wire bond connecting the third contact pad to a third trace on the circuit board; and
a fourth wire bond connecting the fourth contact pad to a fourth trace on the circuit board.
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.
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