Operation of Josephson Junctions With Current Pulses Generated by Triggering a Cold Photo Detector With an Optical Comb

摘要

We report the experimental results on a Josephson junction array (JJA) driven by current pulse trains generated by triggering a photo detector located in a cryostat with an optical comb. The key components in the experimental system are a mode locked fiber laser, a metal-semiconductor-metal (MSM) photoconductive switch, and an overdamped JJA. Optical pulse trains generated at room temperature are transmitted via an optical fiber to the MSM-photo detector installed at 4.2 K, and then converted into electric current pulse trains to drive the overdamped JJA. Quantized voltage steps have been verified at multiples of 10 $mu{rm V}$, which agrees with the repetition rate of the pulse laser and the number of Josephson junctions in the JJA.