Broadband merged-element Josephson parametric amplifier

Abstract: Broadband quantum-limited amplifiers are essential for quantum information processing, yet challenges in design and fabrication continue to hinder their widespread applications. Here, we introduce the broadband merged-element Josephson parametric amplifier in which the discrete parallel capacitor is directly integrated with the Josephson junctions. This merged-element design eliminates the shortcomings of discrete capacitors, simplifying the fabrication process, reducing the need for high-precision lithography tools, and ensuring compatibility with standard superconducting qubit fabrication procedures. Experimental results demonstrate a gain of 15 dB over a 500 MHz bandwidth, a mean saturation power of -116 dBm and near-quantum-limited noise performance. This robust readily implemented parametric amplifier holds significant promise for broader applications in superconducting quantum information and the advancement of quantum computation.