We present experiments on far infrared response of intrinsic Josephson junc
tions in Bi2Sr2CaCu2O8+x. The frequencies we used were between 584 GHz and
762 GHz, well above the plasma frequency of our junctions. By varying the f
requency and the power of the radiation we examined the occurence and stabi
lity of the Shapiro steps. Furthermore the temperature and power dependence
of the step amplitude was investigated.