Techniques relate to an on-chip Josephson parametric converter. A Josephson ring modulator includes four nodes. A lossless on-chip flux line is capacitively coupled to two adjacent nodes of the four nodes of the Josephson ring modulator. The lossless on-chip flux line has an input port configured to receive a pump drive signal that couples differentially to the two adjacent nodes of the of the Josephson ring modulator. The pump drive signal thereby excites a common mode of the on-chip Josephson parametric converter.