Multi-frequency generation in Josephson junction arrays

The phenomenon of multi-frequency generation was discovered during the experimental study of the spectra of electromagnetic radiation of large low-temperature Josephson junction array fabricated on the basis of niobium. The spectrum of the array was measured with the use of a superconducting receiver where the mixer is a high-temperature bicrystal Josephson junction. The numerical simulation of a system similar to the one studied experimentally showed that the multi-frequency generation regime occurs when the system contains eigenmodes with close frequencies.