PARAMETRIC INTERACTIONS IN HIGH-TC SUPERCONDUCTING STEP EDGE JUNCTIONS AT X-BAND

We have fabricated and tested both single junctions and series arrays of YBCO step edge junctions for four photon parametric effects at X ba nd as a first step in developing a parametric amplifier at 60 GHz. The series array of 25 junctions at 10.3 Ghz shows a 10 dB increase in re flected signal power as the pump power is increased, while the single junction at 12.2 GHz indicates a 2 dB change. The reflected power at t he characteristic idler frequency of 2omega(p)-omega(s) is evidence of true Josephson junction parametric interaction. We are currently inve stigating the use of thallium based films at 60 GHz which offer a broa der range of operating temperatures than does YBCO. Our design for a p arametric amplifier at V band is a combination of microstrip based ser ies arrays of junctions and an antipodal finline transition.