Millimeter- and Submillimeter-Wave Phase-Locking in High-Tc Josephson Junction Arrays

Kiejin LEE  Ienari IGUCHI  Karen Y. CONSTANTINIAN  Gennady A. OVSYANNIKOV  Jeha KIM  Kwang-Yong KANG  

IEICE TRANSACTIONS on Electronics   Vol.E80-C   No.10   pp.1275-1281
Publication Date: 1997/10/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Basic Properties and Applications of Superconductive Electron Devices)
Josephson junction array,  high Tc superconductor,  bicrystal substrate,  millimeter-wave,  submillimeter-wave,  phaselocking,  

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We report the strong microwave Josephson radiation from an array of high-Tc junctions on a MgO bicrystal substrate from centimeter- to millimeter-wave ranges. The dc bias current was fed to the junction array having parallel geometry with the pair of junctions shunted by superconducting loops. The configuration of bias leads was a series of interlocking dc SQUID's geometry which guaranteed the oscillation of all junctions at the same frequency. For a five-junctions array, we observed the coherent output power of about 13 pW at receiving frequency fREC22GHz without an external magnetic flux, which was nearly five times higher than that of a single bicrystal junction. We observed the Josephson linewidth of the selfradiation in coherent state less than 1 GHz by the adjustment of the external flux. The phase differences between adjacent junctions with different IcRn products could be controlled by an external small magnetic field. Submillimeter-wave detector response of the five-junction array was also studied experimentally at frequency f478 GHz.