My work on two-dimensional Josephson Junction Arrays

In 1993 I was invited to work on a subject completely different from those studied previously. During the beginning of the nineties there was a growing interest in two-dimensional Josephson Junction Arrays. This is a typical example of such an array:

Josephson junctions (denoted by the crosses above) are nonlinear cryoelectronic elements which, properly cooled and biased, can emit microwave radiation in the GHz range. As these elements are tunable via changing their bias current, there are several potential applications, ranging from mixers to satellite communication. For obtaining a sufficiently high output power, several junctions have to be wired in larger arrays. Unfortunately, it's rather hard to get these junctions to synchronize, especially in 2D arrays where external fluxes may drive the oscillation phases apart.

This work was done in a group headed by Dr.W. Krech, who initiated the project and provided a lot of general ideas, and together with K. Platov, a talented programmer from Moscow university who did the numerical simulations while I did most of the analytical treatment. The main idea was to concentrate on small inductance loops, which guarantee at least in-phase synchronization within the cells  (Phys. Rev. B 52 (1995), 7504-7515, for a PS version click the reference). Synchronizing the junctions along the bias direction seems to be impossible without an inductive external load (J. Appl. Phys. 80 (1996), 3598-3600). For more papers, check my list of publications.

Several resources on Josephson junction networks can be found on the home page of the Supnet network maintained by Carlo Giovanella.

Unfortunately, theoretical treatment as well as actual making of two-dimensional Josephson junction arrays turned out to be much more complicated than it was thought at the beginning of the nineties. At least at present, radiation outcome of these arrays is much below that of proper one-dimensional arrays.

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Online since: 1997
Latest update: 01/04/2007