Isolation of frequency multiplexed microwave signals using cascading multi-path interferometric josephson isolators with nonoverlapping bandwidths

A method to form a cascading microwave isolator (cascade), the method comprising:

• fabricating a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies;
• and
• forming a series coupling between first Josephson device from the set and an nth Josephson device from the set, wherein the series coupling causes the first Josephson device to isolate a signal at a first frequency from a frequency multiplexed microwave signal (multiplexed signal) in a first signal flow direction through the series coupling and the nth Josephson device to isolate a signal at an nth frequency from the multiplexed signal in the first signal flow direction through the series.

A superconductor fabrication system which when operated to fabricate a cascading microwave isolator (cascade) performing operations comprising:

• fabricating a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies;
• and
• forming a series coupling between first Josephson device from the set and an nth Josephson device from the set, wherein the series coupling causes the first Josephson device to isolate a signal at a first frequency from a frequency multiplexed microwave signal (multiplexed signal) in a first signal flow direction through the series coupling and the nth Josephson device to isolate a signal at an nth frequency from the multiplexed signal in the first signal flow direction through the series.