NUMERICAL-ANALYSIS OF THE COHERENT RADIATION EMISSION BY 2 STACKED JOSEPHSON FLUX-FLOW OSCILLATORS

The numerical investigation of the radiation emission by a system of t wo magnetically coupled, long Josephson junctions is reported. Time-de pendent synchronized voltage response in the flux-flow regime is analy zed for the case of in-phase and out-of-phase oscillations in the junc tions. Simulations show that Josephson junctions operating in the in-p hase flux-flow mode may generate rf radiation power by a factor of mor e than 4 larger than that of a single Josephson junction. The radiatio n in the out-of-phase flux-flow mode is characterized by nearly comple tely suppressed amplitudes of odd harmonics and considerably damped ev en harmonics as compared to that of a single barrier junction. The dep endence of the radiation power on the parameter spread between the jun ctions is investigated. The advantages of using stacked Josephson junc tions as oscillators for the sub-mm wave band are discussed. (C) 1996 American Institute of Physics.