DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-4 and 6-20 are rejected under 35 U.S.C. 102 as being anticipated by Tan et. al., (US 2019/0074801 A1).
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Fig. 4A of Tan annotated by the examiner for ease of reference.
Regarding claims 1, Tan teaches a device (3, Fig. 2A), comprising:
a Josephson junction (23a-27c) traveling-wave parametric circuit (3, Fig. 2A) comprising unit cells (such as, 21, denoted by the examiner in the annotated Fig. 4A of Tan) which are coupled in series (see Fig. 4A above) to form a transmission line (21) between an input port (N1-N2) and an output port (N3-N4), each unit cell comprising a series Josephson junction (for example 23a-27c), and a capacitor (for example 25a-29c) shunted to ground (common earth line 41, §0096);
wherein an impedance of the unit cells is varied along the transmission line (The impedance of the wire may be altered in the plurality of regions by altering the width of the wire, §0024) to match an input impedance at the input port to an output impedance at the output port, wherein the input impedance and the output impedance are dissimilar (from the central section of the transmission line. The shape of the tapered section 116b provides for impedance matching between the transmission line and the rest of the system the bonding pads 102a, b connect out to. Typically, the transmission line may have an impedance of 20 Ohms or less. However, the wider system may have an impedance of 50 Ohms or more. Therefore, impedance matching needs to be done, §0193).
wherein per claim 2, the Josephson junction traveling-wave parametric circuit (travelling wave parametric amplifier, §0001) comprises a Josephson traveling-wave frequency converter circuit (The transmission line is used to provide low noise frequency conversion of an input signal through generation of an idler signal, or other inter-mixing harmonics, §0010, §0133).
wherein per claim 3, the Josephson junction traveling-wave parametric circuit comprises a Josephson traveling-wave parametric amplifier circuit, §0001, §0010, Fig. 2A, 4A. The TWPA of Fig. 1A is formed from a transmission line 3, §0068).
wherein per claim 16, Tan teaches a system (Travelling wave parametric amplifiers (TWPAs) utilize long transmission lengths rather than a cavity, and have increased operational bandwidths, §0003), comprising:
a quantum processor comprising quantum bits (the noise of the system is reduced to near the quantum limit, meaning the accuracy of the amplifier approaches qubit measurements, §0002);
a readout signal path configured to transmit signals that are readout from one or more of the quantum bits of the quantum processor (the system is used in a wide range in readout of qubits, where it is capable to detect a single photon, §0002), the readout signal path comprising a Josephson traveling-wave parametric amplifier (TWPA) circuit;
wherein per claims 4 and 16, the Josephson traveling-wave parametric amplifier circuit (FIG. 1A illustrates an example of a travelling wave parametric amplifier (TWPA) 1a. The TWPA 1a is formed from a transmission line 3, §0068) comprising unit cells (the transmission line 3 is formed from a periodic structure having a plurality of repeating unit cells 21 of identical structure, §0088) which are coupled in series to form a transmission line between an input port and an output port, each unit cell comprising a series Josephson junction, and a capacitor shunted to ground (the unit cell 21 comprising of a first set of three Josephson Junctions 23a, 23b, 23c are provided in series, followed by a second set of three Josephson Junctions 27a, 27b, 27c, also connected in series. The Josephson junctions in the first set 23a,b,c are the same as the Josephson junctions in the second set 27a,b,c. Shunt capacitors 2Sa,b,c, 29a,b,c are provided between each of the Josephson Junctions 23a,b,c, 27a,b,c to a common earth line 41 of the circuit, §0096);
wherein an impedance of the unit cells is varied along the transmission line (The impedance of the wire may be altered in the plurality of regions by altering the width of the wire, §0024) to cause the transmission line to have an increased effective electrical length compared to an unvaried impedance (The inductance of the inductor 39 can be tuned by varying the width and length of the path 114. In the example shown in FIG. 9B, the conductance path 114 doubles back on itself a few times, parallel to the fingers 112a, b of the capacitor, to create the correct length path 114 without using too much space on the chip 100, §0186).
Further per claims 6 and 17, the impedance of the unit cells is varied along the transmission line by varying a capacitance of the capacitors of the unit cells (the capacitance of the capacitor 37 can be tuned by varying the width and spacing of the tracks 110a, band the width, spacing and number of the fingers 112a, b, §0185).
wherein per claims 7 and 18, the impedance of the unit cells is varied along the transmission line by varying (varying the current of the pumps I*, §0212) a critical current of the Josephson junctions (The Josephson junctions 23, 27 are modelled to have critical current of =3.29 mAmps, §0102) of the unit cells.
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Fig. 9C of Tan reproduced by the examiner for ease of reference.
Also, per claims 8, 11-12 and 19-20, Tan further teaches in Fig. 9C that the impedance of the unit cells is varied along the transmission line (The transmission line, 100, Fig. 9A is a microstrip line formed of a conducting layer 104 provided on a substrate 106, §0180) by progressively decreasing the impedance (by progressively decreasing the width) of unit cells along a first portion (tapered portion 116b tapered from the wide section 116a provides an area for connection into the wider system at the input side, §0192) of the transmission line (100) and progressively increasing the impedance (by progressively increasing the width) of unit cells along a second portion (tapered portion 116b tapers out the wide section 116a provides an area for connection to the wider system at the output side, §0192) of the transmission line (100).
Wherein per claim 9, the first portion of the transmission line extends from the input port (102a, Fig. 9A) to a central region of the transmission line; and
the second portion of the transmission line extends from the central regi0n of the transmission line to the output port (102b, Fig. 9A).
wherein per claim 10, the central region of the transmission line (3, Fig. 3) comprises a plurality of unit cells (21, Fig. 3) providing a constant impedance (approximately 20 ohms, §0193) over the central region of the transmission line (3).
wherein per claim 13, the Josephson traveling-wave parametric amplifier circuit (comprising of the unit cells 21 of transmission lines as shown in Figs. 6A, 10) comprises a plurality of dispersion resonators (Stopbands in the form of resonance, §0202) are created in the dispersion relationship by providing periodic loading on the wire 47 (Figs. 6A, 10) that are coupled to different points (by providing periodic loading, §0202) along the transmission line (47) using respective coupling capacitors (shunt resonators 33 as exemplarily shown in Figs. 6A, 10).
wherein per claim 14, the Josephson traveling-wave parametric amplifier circuit (as exemplarily shown in Fig. 2A) is configured to perform four-wave mixing (§0085, Fig. 2B) of a signal and pump tone applied to the input port (the energy of the pump signals 7a, b, the input signal 5 and the idler signal 9. Energy is transferred from both pump signals 7a, 7b, to the input signal 5, which is amplified, as shown schematically in FIG. 2A, §0085).
wherein per claim 15, Tan also teaches that the Josephson traveling-wave parametric amplifier circuit comprises less than 1200-unit cells (FIG. 7 shows the gain for a KITWPA 1b having 224 repeating unit cells 21).
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.
The factual inquiries 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.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Tan in view of Abdo (US 20180285760 A1).
According to claim 5, Tan teaches all limitations of claim 4, Tan also teaches that that the impedance of the unit cells is varied (progressively increasing from 20 ohms to 50 ohms or decreasing from 50 ohms to 20 ohms by progressively increasing or decreasing the width) along the transmission line (The transmission line, 100, as in Fig. 9A is a microstrip line formed of a conducting layer 104 provided on a substrate 106, §0180, wherein the tapered portion 116b tapered from the wide section 116a provides an area for connection into the wider system at the input side or vice versa for the output side, §0192) of the transmission line at least a portion of the transmission line (i.e. at the input side as well as the output side, please Figs. 9A and 9C).
Tan, however, is not explicit that the variation is exponential with respect to electrical length.
Abdo teaches in a similar filed of endeavor in one implementation (Fig. 5) teaches the wideband impedance transformer 510 as an impedance matching transmission line where one end has a narrow width matching the high impedance ZH of the bandpass filters 405 (via common node 415) while the opposite end has a wide width matching the output impedance Z0 (50 ohms). Such a wideband impedance transformer 510 is best implemented using exponential Taper or the Klopfenstein Taper.
A person of ordinary skill in the art would find it obvious to increase or decrease the impedance at the input or output section of Tan’s JJ transmission line utilized as a parametric amplifier impedance matching using exponential Taper for best possible bandwidth at a minimum possible electrical length. Thereby teaching all limitations of claim 5.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HAFIZUR RAHMAN whose telephone number is (571)270-0659. The examiner can normally be reached M-F: 10-6.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Andrea Lindgren Baltzell can be reached on (571) 272-1769. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
/HAFIZUR RAHMAN/Primary Examiner, Art Unit 2843.