Non-reciprocal parametric amplifiers: Theory and instrumentation

The advantages of a non-reciprocal parametric amplifier over conventional types are manifest. Perturbations in signal source characteristics no longer degrade stability and power gain. For this reason, conventional paramps require circulators. But circulators are noisy, temperature sensitive, and complicate any attempts to cool the paramp cryogenically. To overcome these difficulties, this paper discusses the theory of non-reciprocity and applies it to two single-varactor paramps. One paramp operates in a CW mode, the other is super-regenerative. Both units will (a) provide down-conversion and (b) accommodate signal frequencies which exceed the nominal value of the pump. Design constraints and performance characteristics are discussed.