Josephson analog amplifier with large current gain

Analog amplifiers utilizing the flux-flow phenomenon in a long Josephson tunnel junction, Flux-Flow Amplifier(FFA), have been studied experimentally. The operation of the amplifier is based on the modulation of dc I-V curves of a long Josephson junction by applied magnetic fields, which acts as a magnetic-field to voltage transducer. Strong dependences of the transducer characteristics on junction parameters and geometries are elucidated. Experiments on a series array of FFA´s for higher current gains and larger output voltages were also carried out successfully.