On the behaviour of a two dimensional Josephson tunnel junction in the weakly non-linear regime

A low-current density - large area, quadratic Josephson junction was investigated. The experimental set-up, designed for the investigation of chaos bifurcations, allowed a measurement of the frequency spectrum up to and above the maximum plasma frequency (
\omega_{o}/2\pi
= 770 MHz) by means of a directly connected low noise 5 - 1000 MHz amplifier. The fundamental cavity resonance frequency (
\omega_{c}/2\pi
) in the linear limit was 4.3 GHz. The non-linear phenomena observed included (i) parametric half harmonic generation with
\omega_{pump} \lsim 2\omega_{o}
(ii) parametric excitation of the plasma mode with
\omega_{pump} \sim\omega_{o}+\omega_{c}
(iii) selfpumped excitation of a "Fiske mode in one direction or a zero field" mode in the other (iv) selfpumped excitation of a two-dimensional mixed "Fiske mode" in a magnetic field. (v) rf induced cavity resonance steps at voltages V = (h/2e)(
m\omega_{c} \pm n\omega_{pump}
) and (vi) usual rf induced
\omega_{pump} > \omega_{o}
. In spite of sufficient receiver sensitivity chaos bifurcations were not observed where simple theory predicts it.