Superconducting square pulse waveform generators

A device, comprising:

• a superconducting square pulse waveform generator which comprises:
• a first superconducting sub-circuit;
• and
• a second superconducting sub-circuit which comprises a quantizing inductor;
• wherein the first superconducting sub-circuit is configured to receive a single flux quantum (SFQ) pulse applied to an input port of the superconducting square pulse waveform generator, and propagate the SFQ pulse around the first superconducting sub-circuit to periodically inject (i) a first SFQ pulse into the second superconducting sub-circuit to cause a first circulating current to flow in a first direction through the quantizing inductor, and (ii) a second SFQ pulse into the second superconducting sub-circuit to cause a second circulating current to flow through the quantizing inductor in a second direction, opposite the first direction, to cancel the first current and thereby generate a square current pulse.

A method, comprising:

• receiving, by a superconducting square pulse waveform generator, a single flux quantum (SFQ) pulse;
• and
• generating, by the superconducting square pulse waveform generator, a continuous sequence of square current pulses in response to the SFQ pulse;
• wherein generating the continuous sequence of square current pulses comprises propagating the received SFQ pulse around a first superconducting sub-circuit of the superconducting square pulse waveform generator to periodically inject (i) a first SFQ pulse into a second superconducting sub-circuit of the superconducting square pulse waveform generator to cause a first circulating current to flow in a first direction through a quantizing inductor, and (ii) a second SFQ pulse into the second superconducting sub-circuit to cause a second circulating current to flow through the quantizing inductor in a second direction, opposite the first direction, to cancel the first current and thereby generate a square current pulse.