Superconductor Science and Technology

A superconducting phase-locked local oscillator for a submillimetre integrated receiver

V. P. Koshelets, S. V. Shitov, Lyudmila V. Filippenko, Pavel N. Dmitriev, An. B. Ermakov, Alexander S. Sobolev, Mikhail Yu. Torgashin, A. L. Pankratov, Vladislav V. Kurin, Pavel A. Yagoubov, Ruud W. M. Hoogeveen

Published Feb 19, 2004• 11 citations

Publisher

Abstract

Comprehensive measurements of the flux flow oscillator (FFO) radiation linewidth are performed using an integrated harmonic SIS mixer; the FFO linewidth and spectral line profile are compared to a theory. An essential dependence of the FFO linewidth on frequency is found; a possible explanation is proposed. The results of the numerical solution of the perturbed sine–Gordon equation qualitatively confirm this assumption. To optimize the FFO design, the influence of the FFO parameters on the radiation linewidth is studied. A novel FFO design at a moderate current density has resulted in a free-running FFO linewidth of about 10 MHz in the flux flow regime up to 712 GHz, limited only by the gap frequency of Nb. This relatively narrow free-running linewidth (along with implementation of a wide-band phase locking loop system) allows continuous phase locking of the FFO in the wide frequency range of 500–710 GHz. These results are the basis for the development of a 550–650 GHz integrated receiver for the terahertz limb sounder (TELIS) intended for atmosphere study and scheduled to fly on a balloon in 2005. We report here also on the design of the second generation of the phase-locked superconducting integrated receiver chip for TELIS.

DOI: 10.1088/0953-2048/17/5/007

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