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Description
We present the development of a kinetic-inductance traveling-wave parametric amplifier (KI-TWPA) based on NbTiN and TiN microstrip transmission lines optimized for sub-GHz and GHz frequency ranges. KI-TWPAs exploit nonlinear mixing processes enabled by the kinetic inductance of superconducting transmission lines, delivering wide instantaneous bandwidth, near quantum-limited noise performance, and high dynamic range. Our devices amplify signals via a four-wave mixing mechanism, achieving a tunable gain of up to 22 dB in the sub-GHz range. In the 4 to 8 GHz band, which is commonly used for cryogenic detector readout and superconducting qubits, the amplifier demonstrated a peak gain exceeding 20 dB, with amplifier-added noise as low as 0.5 to 1.5 photons. The device gain of the KI-TWPAs is tunable in that the gain can be adjusted based on the frequency of the pump tone. This feature makes the KI-TWPA suitable for applications where the signal frequency range needs to be changed, such as in dark matter experiments. Additionally, the higher frequency idler band of the KI-TWPA can be used instead of the signal band to search for dark matter candidates with a higher mass range. This dual-band operation can be achieved without making significant changes to the readout circuitry.
