Quantum Noise Studies with Superconducting Tunnel Junction Mixers.

摘要

We have completed our theoretical and experimental investigations of the noise properties of superconducting tunnel junction (SIS) mixers operated as both a phase insensitive linear amplifier and as a phase sensitive linear amplifier. We proposed a technique by which a SIS mixer could be operated as a phase sensitive linear amplifier, i.e., the gain and noise temperature of the amplifier are a function of the phase of the incoming signal. In this technique two phase coherent local oscillators at different frequencies are combined in the mixer simultaneously so both a phase preserving and phase conjugating mixing process occur resulting in a phase sensitive mixer.