Submillimeter wave generation using Josephson junction arrays

A submillimeter-wave oscillator using a phase-locked array of Josephson junctions is demonstrated. With an array of 40 shunted tunnel junctions, the oscillator delivers 1 mu W of power at 350 GHz into a 60- Omega load on the chip. The operating frequency of the oscillator is tunable over a range of about 10%. Experiments on two coupled lead alloy tunnel junctions show that Josephson oscillations exist to about 1 THz. Using a similar design and a higher gap superconductor such as NbN for the transmission lines, arrays operating at 1 THz with power outputs of 1 mW should be feasible.>