Broadband quantum-limited parametric amplifiers (PAs) are essential
components in quantum information science and technology. Impedance-engineered
resonator-based PAs and traveling-wave PAs are the primary approaches to
overcome the gain-bandwidth constraint. While the former PAs are simpler to
fabricate, the target characteristic impedance Z_\text{NR} of the nonlinear
resonator has been restricted to be below 10 \Omega, requiring large
capacitance. Moreover, these PAs have only been implemented with aluminum-based
Josephson junctions (JJs), hindering their operation at high temperatures or
strong magnetic fields. To address these issues, we propose a three-stage
impedance-transformer scheme, showcased with a 20-nm-thick, 250-nm-wide
high-kinetic-inductance niobium-titanium-nitride (NbTiN) film. Our scheme
enables Z_\text{NR} up to several tens of ohms–a tenfold improvement over
conventional designs, achieved through an additional quarter-wavelength
transmission line with the characteristic impedance of 180 \Omega. Our
kinetic-inductance impedance-engineered parametric amplifiers (KIMPA),
featuring a 330-fF shunt capacitor, demonstrate a phase-preserving
amplification with a 450-MHz bandwidth at 17-dB gain, and an added noise
ranging from 0.5-1.3 quanta near the center frequency of 8.4 GHz. Due to the
high critical current of the NbTiN nanowire, the KIMPA also achieves a
saturation power of up to -68\pm3 dBm, approximately 30-dB higher than that of
JJ-based PAs. This scheme also opens new possibilities for other
three-wave-mixing building blocks.

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