RADIATION LINEWIDTH OF PHASE-LOCKED DISTRIBUTED ARRAY IN THE SUBMILLIMETER-WAVE RANGE

The radiation linewidth of a phase-locked distributed Josephson junction array source at 250 GHz has been measured as a function of temperature using an integrated submillimeter wave receiver/source. The measured total linewidth (including signal and local oscillator arrays, having 10 junctions each) is 10 MHz at 1.6 K. The measured data agree, within 50% uncertainty, with the linewidth obtained from computer simulation assuming the Nyquist noise current spectral density generated by the junction shunt resistors.