# US 11,451,204 B2 · Josephson parametric amplifier based on superconducting-normal-superconducting junction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,204 B2 - Document ID: US11451204B2 - Status: Granted - Kind: B2 - Application number: 16/796,871 - Filed: 2020-02-20 - Published: 2020-08-27 - Granted: 2022-09-20 - Earliest claimed: 2019-02-22 - Assignees: Raytheon BBN Technologies Corp. - Applicants: Raytheon Bbn Technologies Corp. - Inventors: Kin Chung Fong; Guilhem Ribeill; Luke Colin Gene Govia; Martin Gustafsson; Thomas A. Ohki - Web page: https://patentgrep.com/patent/US11451204B2 ## CPC - H03F 19/00: Amplifiers using superconductivity effects - H10N 60/12: Josephson-effect devices - H10N 60/128: {having three or more electrodes, e.g. transistor-like structures} - H03F: AMPLIFIERS - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract An amplifier. In some embodiments, the amplifier includes a resonant circuit having a resonant frequency, a pump input, a signal input, and a signal output. The resonant circuit may include a Josephson junction connected to the pump input, the Josephson junction being a superconducting-normal-superconducting junction having two superconducting terminals and being configured to adjust the resonant frequency of the resonant circuit based on a signal received at the pump input. ## Claims ### Claim 1 An amplifier, comprising: a resonant circuit, having a resonant frequency; a pump input; a signal input; and a signal output, the resonant circuit comprising a Josephson junction connected to the pump input, the Josephson junction being a superconducting-normal-superconducting junction having two superconducting terminals and being configured to adjust the resonant frequency of the resonant circuit based on a signal received at the pump input, wherein: the resonant circuit is a resonant transmission-line circuit comprising a first section of transmission line and a second section of transmission line, and the two superconducting terminals of the Josephson junction are connected in series between the first section of transmission line and the second section of transmission line. ### Claim 2 (depends on 1) The amplifier of claim 1, wherein the pump input is the same input as the signal input. ### Claim 3 (depends on 1) The amplifier of claim 1, wherein the first section of transmission line has a length that is about the same as a length of the second section of transmission line. ### Claim 4 (depends on 1) The amplifier of claim 1, wherein the first section of transmission line has a length that is about one quarter of one wavelength at the resonant frequency. ### Claim 5 An amplifier, comprising: a resonant circuit, having a resonant frequency; a pump input; a signal input; and a signal output, the resonant circuit comprising a Josephson junction connected to the pump input, the Josephson junction being a superconducting-normal-superconducting junction having two superconducting terminals and being configured to adjust the resonant frequency of the resonant circuit based on a signal received at the pump input, wherein: the Josephson junction has a gap comprising a portion of a graphene sheet, and the Josephson junction has a control terminal for adjusting a series inductance of the Josephson junction, the control terminal being connected to the pump input. ### Claim 6 (depends on 5) The amplifier of claim 5, wherein the graphene sheet comprises two atomic layers of graphene. ### Claim 7 (depends on 5) The amplifier of claim 5, wherein the two superconducting terminals are composed of a material selected from the group consisting of niobium nitride, niobium titanium nitride, niobium diselenide, aluminum, niobium, niobium titanium, and lead. ### Claim 8 (depends on 5) The amplifier of claim 5, wherein the control terminal is connected to a conductive gate on the portion of the graphene sheet. ### Claim 9 (depends on 8) The amplifier of claim 8, wherein: the graphene sheet is a middle layer of a graphene stack comprising: a first layer of hexagonal boron nitride immediately adjacent a first surface of the graphene sheet, the graphene sheet, and a second layer of hexagonal boron nitride immediately adjacent a second surface of the graphene sheet; and the conductive gate is directly on the graphene stack. ### Claim 10 (depends on 5) The amplifier of claim 5, wherein the graphene sheet is a middle layer of a graphene stack comprising: a first layer of hexagonal boron nitride immediately adjacent a first surface of the graphene sheet, the graphene sheet, and a second layer of hexagonal boron nitride immediately adjacent a second surface of the graphene sheet. ### Claim 11 (depends on 5) The amplifier of claim 5, wherein the graphene sheet has an electron mobility of more than 100,000 cm2/V/s. ### Claim 12 (depends on 10) The amplifier of claim 10, further comprising a substrate, the two superconducting terminals and the graphene stack being on the substrate. ### Claim 13 (depends on 12) The amplifier of claim 12, wherein the substrate is a float zone crystalline silicon substrate. ### Claim 14 (depends on 10) The amplifier of claim 10, wherein each of the first layer of hexagonal boron nitride and the second layer of hexagonal boron nitride has a thickness greater than 0.3 nm and less than 100 nm. ### Claim 15 (depends on 9) The amplifier of claim 9, further comprising a gate insulating layer directly on the graphene stack, the conductive gate being directly on the gate insulating layer. ### Claim 16 (depends on 15) The amplifier of claim 15, wherein the gate insulating layer is composed of aluminum oxide. ### Claim 17 (depends on 15) The amplifier of claim 15, wherein the graphene sheet consists of a single atomic layer of graphene.