Nonreciprocal amplification via Hamiltonian Engineering

In superconducting quantum information processing, we realize high fidelity measurements by using quantum-limited parametric processes. However, cavity-based amplifiers have limited bandwidth, saturation power, and operate in reflection, and so must be operated with external lossy microwave commercial components such as circulators. Many of these limitations can be circumvented by combining multiple parametric processes in a few-mode device. By combining multiple instances of imbalanced gain and conversion processes between three modes[1], we can realize an amplifier with non-reciprocal, transmission-only amplification, matched ports, and large, gain-independent bandwidth. We have realized this scheme in a Lumped, single-ended version of the Josephson Parametric Converter (LJPC) whose inductance is dominated by the central Josephson Ring Modulator. We avoid the use of hybrids by integrating the LJPC and superconducting bandpass filters on a single chip. The resulting device is small, relatively simple to fabricate and thus an excellent candidate for direct integration into superconducting quantum computers.


[1] A. Metelmann and A. A. Clerk, PRX, 5, 021025 (2015)