Subharmonic locking in Josephson junctions

We have designed and tested a coplanar waveguide configuration which allows for coupling and detection of microwave radiation to planar and stacked Josephson junctions structures. The design is particularly versatile for experiments such as phase-locking of Josephson oscillations to external signals and detection of low frequency components in the waveform of a pumped junction. Using this design we have measured subharmonic phase-locking in long Josephson junctions and performed a first quantitative check of the existing theoretical models.