3 research outputs found
Time-walk and jitter correction in SNSPDs at high count rates
Superconducting nanowire single-photon detectors (SNSPDs) are a leading
detector type for time correlated single photon counting, especially in the
near-infrared. When operated at high count rates, SNSPDs exhibit increased
timing jitter caused by internal device properties and features of the RF
amplification chain. Variations in RF pulse height and shape lead to variations
in the latency of timing measurements. To compensate for this, we demonstrate a
calibration method that correlates delays in detection events with the time
elapsed between pulses. The increase in jitter at high rates can be largely
canceled in software by applying corrections derived from the calibration
process. We demonstrate our method with a single-pixel tungsten silicide SNSPD
and show it decreases high count rate jitter. The technique is especially
effective at removing a long tail that appears in the instrument response
function at high count rates. At a count rate of 11.4 MCounts/s we reduce the
full width at one percent maximum level (FW1%M) by 45%. The method therefore
enables certain quantum communication protocols that are rate-limited by the
(FW1%M) metric to operate almost twice as fast. \c{opyright} 2022. All rights
reserved.Comment: 5 pages, 3 figure
Entangled Photon Pair Source Demonstrator using the Quantum Instrumentation Control Kit System
We report the first demonstration of using the Quantum Instrumentation and
Control Kit (QICK) system on RFSoCFPGA technology to drive an entangled photon
pair source and to detect the photon signals. With the QICK system, we achieve
high levels of performance metrics including coincidence-to-accidental ratio
exceeding 150, and entanglement visibility exceeding 95%, consistent with
performance metrics achieved using conventional waveform generators. We also
demonstrate simultaneous detector readout using the digitization functional of
QICK, achieving internal system synchronization time resolution of 3.2 ps. The
work reported in this paper represents an explicit demonstration of the
feasibility for replacing commercial waveform generators and time taggers with
RFSoC-FPGA technology in the operation of a quantum network, representing a
cost reduction of more than an order of magnitude