Three-wave mixing with three incoming waves: signal-idler coherent attenuation and gain enhancement in a parametric amplifier.

We demonstrate the time-reversed process of nondegenerate three-wave parametric amplification from three distinct sources in the fully nonlinear regime using a Josephson amplifier. In the reverse process, coherent attenuation, signal and idler beams destructively interfere in the presence of a pump to generate additional pump photons. This effect is observed through the symmetric phase-dependent amplification and attenuation of the signal and idler beams and, in the depleted pump regime, through the phase-dependent modulation of the amplifier gain, directly probing the enhancement of the pump. Results are found to be in good agreement with theory.