Quasi-optical Josephson-junction oscillator arrays

Josephson junctions are natural voltage-controlled oscillators capable of generating submillimeter-wave-length radiation, but a single junction usually can produce only 100 nW of power and often has a broad spectral linewidth. The authors are investigating 2-D quasi-optical power combining arrays of 10/sup 3/ and 10/sup 4/ NbN/MgO/NbN and Nb/Al-AlO/sub x//Nb junctions to overcome these limitations. The junctions are DC biased in parallel and are distributed along interdigitated lines. The arrays couple to a resonant mode of a Fabry-Perot cavity to achieve mutual phase-locking. The array configuration has a relatively low impedance, which should allow the capacitance of the junctions to be tuned out at the oscillation frequency.<
>