Josephson Array-Mode Parametric Amplifier

We introduce a near-quantum-limited amplifier with a large tunable bandwidth and high dynamic range—the Josephson array-mode parametric amplifier (JAMPA). The signal and idler modes involved in the amplification process are realized by the array modes of a chain of 1000 flux-tunable Josephson-junction-based nonlinear elements. The frequency spacing between the array modes is comparable to the flux tunability of the modes, ensuring that any desired frequency can be occupied by a resonant mode, which can further be pumped to produce high gain. We experimentally demonstrate that the device can be operated as a nearly quantum-limited parametric amplifier with 20 dB of gain at almost any frequency within a 4-12-GHz band. On average, it has a 3-dB bandwidth of 11 MHz and an input 1-dB compression power of -108 dBm , which can go as high as -93 dBm . We envision the application of such a device to the time- and frequency-multiplexed readout of multiple qubits, as well as to the generation of continuous-variable cluster states.