SUPERCONDUCTING MILLIMETER-WAVE OSCILLATORS

The integrated superconducting mm wave oscillator have been designed and experimentally investigated. It consists of Flux Flow oscillator (FFO), coupling section and detector junction with tuned out capacitance. Oscillator is long Josephson junction with nonuniform current injection shunted by Mo resistor to obtain dissipation parameter alpha approximately 0.5. Coupling section is designed as microstrip quarter-wave three step transformer with dc-block between oscillator and detector. All refractory material integrated circuits have been fabricated on the base of high quality Nb-AlOx-Nb junctions. The oscillations in the ranges 75 - 260 GHz have been experimentally observed. The values of the generated power have been calculated from the amplitudes of the quasiparticle and Shapiro steps on the I-V curve of the detector junctions. The detected power levels higher than 0.1 muW have been obtained. The linewidth value of FFO not more than 1 MHz has been experimentally estimated.