Demonstration of Individual Readout of Serially-Connected Superconducting Strip Line Detectors

We report successful demonstration of individual readout of the response to an optical signal in serially-connected superconducting strip line detectors (SSLDs). Based on the numerical analysis, placement of low-pass filters between adjacent SSLDs and use of a current-source drive enable serially-connected SSLDs to work as independent multiple SSLDs. This leads to reduction of the number of cables from room temperature electronics. We irradiate a laser just on a certain SSLD (SSLD#1) with On/Off modulation. Synchronized voltage output is obtained at only corresponding SQUID. Then we move the position of a laser spot on the neighbor SSLD (SSLD#2). The voltage disappears at the SQUID connecting to SSLD#1, and the voltage is developed only at the SQUID connecting to SSLD#2. We have also given a demonstration of readout using the single-flux-quantum circuits connected to the SQUIDs. We confirmed from those experimental results that our driving method for multiple SSLDs is effective not only to enhance detecting area but also to obtain position sensitivity.