Design and demonstration of an on-chip AC power source for adiabatic quantum-flux-parametron logic

Adiabatic quantum-flux-parametron (AQFP) logic is a promising technology for use in future high-end computers because its bit energy can be potentially reduced to the order of thermal energy. AQFP gates are driven by an AC bias current, which changes their potential energy adiabatically. In the present paper, we propose an on-chip AC power source, which is composed of a Josephson relaxation oscillator and a superconducting resonator, to drive the AQFP gates. We designed and implemented the AC power source using a Nb Josephson integrated circuit process. We confirmed that the AC power source can generate a 4.4 GHz sinusoidal current from a DC bias current and that the output amplitude of the AC power source can be controlled by varying the DC bias current.