MEASUREMENT OF PARAMETRIC INTERACTIONS IN YBA2CU3O7-X STEP-EDGE JUNCTIONS

We have fabricated and tested series arrays of YBa2Cu3O7-x (YBCO) step edge junctions for four photon parametric effects at 10 GHz. The seri es array of 25 junctions shows a 10 dB increase in reflected signal po wer as the pump power is increased at 10 K. At 50 K the reflected sign al power shows a 3 dB increase. The reflected power at the characteris tic idler frequency of 2omega(p)-omega(s), suggests four photon parame tric interaction. In addition, an anomalous gain saturation effect is experimentally observed whereby the reflected signal power maintains a constant increased value even as the reflected idler power decreases.