# US 2019/0173445 A1 · Amplification of frequency multiplexed microwave signals using cascading multi-path interferometric josephson directional amplifiers with nonoverlapping bandwidths > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0173445 A1 - Document ID: US20190173445A1 - Status: Published application - Kind: A1 - Application number: 15/829,099 - Filed: 2017-12-01 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: BALEEGH ABDO - Web page: https://patentgrep.com/patent/US20190173445A1 ## CPC - H03F 19/00: Amplifiers using superconductivity effects - H03F 7/00: Parametric amplifiers - H03K 3/38: by the use, as active elements, of superconductive devices - H03K 19/195: using superconductive devices - H10N 60/0912: {of Josephson-effect devices} - H10N 60/12: Josephson-effect devices - H03F: AMPLIFIERS - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract A cascading microwave directional amplifier (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an nth Josephson device from the set, such that the first Josephson device amplifies a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and propagate without amplification a signal of an nth frequency, and the nth Josephson device to amplify the signal of the nth frequency and propagate without amplification the signal of the first frequency from the multiplexed signal in the first signal flow direction through the series. ## Claims ### Claim 1 A cascading microwave directional amplifier (cascade) comprising: a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies; and a series coupling between first Josephson device from the set and an nth Josephson device from the set, wherein the series coupling causes the first Josephson device to amplify a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and propagate without amplification a signal of an nth frequency from the multiplexed signal in a first signal flow direction through the series coupling, and the nth Josephson device to amplify the signal of the nth frequency and propagate without amplification the signal of the first frequency from the multiplexed signal in the first signal flow direction through the series. ### Claim 2 (depends on 1) The cascade of claim 1, further comprising: an (n−1)th Josephson device from the set in the series coupling, wherein n is greater than 1, wherein the (n−1)th Josephson device is included the series coupling between the first Josephson device and the nth Josephson device, and wherein the (n−1)th Josephson device amplifies a signal of an (n−1)th frequency from the multiplexed signal in the first signal flow direction. ### Claim 3 (depends on 1) The cascade of claim 1, wherein the series coupling causes the first Josephson device to propagate without amplification the signal of the nth frequency from the multiplexed signal in the first signal flow direction through the series coupling and the nth Josephson device to propagate without amplification the signal of the first frequency in the first signal flow direction through the series. ### Claim 4 (depends on 1) The cascade of claim 1, wherein the series coupling causes the first Josephson device and the nth Josephson device to propagate without amplification signals of all frequencies from the multiplexed signal in a second signal flow direction through the series coupling, wherein the second signal flow direction is opposite of the first signal flow direction, and wherein the first signal flow direction is a direction of amplification of the first Josephson device and the nth Josephson device. ### Claim 5 (depends on 1) The cascade of claim 1, wherein a first operating bandwidth of microwave frequencies corresponding to the first Josephson device is nonoverlapping for at least some frequencies with an nth operating bandwidth of microwave frequencies corresponding to the nth Josephson device. ### Claim 6 (depends on 5) The cascade of claim 5, wherein a total amplification bandwidth of the cascade comprises the first operating bandwidth and the nth operating bandwidth. ### Claim 7 (depends on 1) The cascade of claim 1, wherein the first Josephson device in the set of Josephson devices is an MPIJDA, comprises: a first nondegenerate microwave parametric amplifier device (first parametric amplifier); a second nondegenerate microwave parametric amplifier device (second parametric amplifier); a first input/output (I/O) port coupled to an input port of the first parametric amplifier and an input port of the second parametric amplifier; and a second I/O port coupled to the input port of the first parametric amplifier and the input port of the second parametric amplifier, wherein the signal of a first frequency communicated between the first I/O port and the second I/O port is transmitted while propagating in a first direction between the first I/O port to the second I/O port through the first parametric amplifier and the second parametric amplifier and is substantially unamplified while propagating in a second direction between the second I/O port to the first I/O through the first parametric amplifier and the second parametric amplifier, and wherein the first frequency is in a first operating bandwidth of the first Josephson device. ### Claim 8 (depends on 7) The cascade of claim 7, further comprising: a first microwave pump injecting a first microwave drive into the first parametric amplifier at a pump frequency and a first pump phase, wherein the first microwave pump is configured to cause the first parametric amplifier to operate at a low power gain working point; and a second microwave pump injecting a second microwave drive into the second parametric amplifier at the pump frequency and a second pump phase wherein the second microwave pump is configured to cause the second parametric amplifier to operate at the low power gain working point. ### Claim 9 (depends on 7) The cascade of claim 7, wherein the first parametric amplifier and the second parametric amplifier are each a nondegenerate three-wave-mixing parametric amplifier. ### Claim 10 (depends on 7) The cascade of claim 7, wherein the first parametric amplifier and the second parametric amplifier are each a Josephson parametric converter (JPC), and wherein the first parametric amplifier and the second parametric amplifier are nominally identical. ### Claim 11 A method to form a cascading microwave directional amplifier (cascade), the method comprising: fabricating a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies; and forming a series coupling between first Josephson device from the set and an nth Josephson device from the set, wherein the series coupling causes the first Josephson device to amplify a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and propagate without amplification a signal of an nth frequency from the multiplexed signal in a first signal flow direction through the series coupling, and the nth Josephson device to amplify the signal of the nth frequency and propagate without amplification the signal of the first frequency from the multiplexed signal in the first signal flow direction through the series. ### Claim 12 A superconductor fabrication system which when operated to fabricate a cascading microwave directional amplifier (cascade) performing operations comprising: fabricating a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies; and forming a series coupling between first Josephson device from the set and an nth Josephson device from the set, wherein the series coupling causes the first Josephson device to amplify a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and propagate without amplification a signal of an nth frequency from the multiplexed signal in a first signal flow direction through the series coupling, and the nth Josephson device to amplify the signal of the nth frequency and propagate without amplification the signal of the first frequency from the multiplexed signal in the first signal flow direction through the series. ### Claim 13 (depends on 12) The superconductor fabrication system of claim 12, further comprising: an (n−1)th Josephson device from the set in the series coupling, wherein n is greater than 1, wherein the (n−1)th Josephson device is included the series coupling between the first Josephson device and the nth Josephson device, and wherein the (n−1)th Josephson device amplifies a signal of an (n−1)th frequency from the multiplexed signal in the first signal flow direction. ### Claim 14 (depends on 12) The superconductor fabrication system of claim 12, wherein the series coupling causes the first Josephson device to propagate without amplification the signal of the nth frequency from the multiplexed signal in the first signal flow direction through the series coupling and the nth Josephson device to propagate without amplification the signal of the first frequency in the first signal flow direction through the series. ### Claim 15 (depends on 12) The superconductor fabrication system of claim 12, wherein the series coupling causes the first Josephson device and the nth Josephson device to propagate without amplification signals of all frequencies from the multiplexed signal in a second signal flow direction through the series coupling, wherein the second signal flow direction is opposite of the first signal flow direction, and wherein the first signal flow direction is a direction of amplification of the first Josephson device and the nth Josephson device. ### Claim 16 (depends on 12) The superconductor fabrication system of claim 12, wherein a first operating bandwidth of microwave frequencies corresponding to the first Josephson device is nonoverlapping for at least some frequencies with an nth operating bandwidth of microwave frequencies corresponding to the nth Josephson device. ### Claim 17 (depends on 16) The superconductor fabrication system of claim 16, wherein a total amplification bandwidth of the cascade comprises the first operating bandwidth and the nth operating bandwidth. ### Claim 18 (depends on 12) The superconductor fabrication system of claim 12, wherein the first Josephson device in the set of Josephson devices is an MPIJDA, comprises: a first nondegenerate microwave parametric amplifier device (first parametric amplifier); a second nondegenerate microwave parametric amplifier device (second parametric amplifier); a first input/output (I/O) port coupled to an input port of the first parametric amplifier and an input port of the second parametric amplifier; and a second I/O port coupled to the input port of the first parametric amplifier and the input port of the second parametric amplifier, wherein the signal of a first frequency communicated between the first I/O port and the second I/O port is transmitted while propagating in a first direction between the first I/O port to the second I/O port through the first parametric amplifier and the second parametric amplifier and is substantially unamplified while propagating in a second direction between the second I/O port to the first I/O through the first parametric amplifier and the second parametric amplifier, and wherein the first frequency is in a first operating bandwidth of the first Josephson device. ### Claim 19 (depends on 18) The superconductor fabrication system of claim 18, further comprising: a first microwave pump injecting a first microwave drive into the first parametric amplifier at a pump frequency and a first pump phase, wherein the first microwave pump is configured to cause the first parametric amplifier to operate at a low power gain working point; and a second microwave pump injecting a second microwave drive into the second parametric amplifier at the pump frequency and a second pump phase wherein the second microwave pump is configured to cause the second parametric amplifier to operate at the low power gain working point. ### Claim 20 (depends on 18) The superconductor fabrication system of claim 18, wherein the first parametric amplifier and the second parametric amplifier are each a nondegenerate three-wave-mixing parametric amplifier.