Active quenching of superconducting nanowire single photon detectors

Abstract

Superconducting nanowire single photon detectors are typically biased using a constant current source and shunted in a conductance which is over an order of magnitude larger than the peak normal domain conductance of the detector. While this design choice is required to ensure quenching of the normal domain, the use of a small load resistor limits the pulse amplitude, rising-edge slew rate, and recovery time of the detector. Here, we explore the possibility of actively quenching the normal domain, thereby removing the need to shunt the detector in a small resistance. We first consider the theoretical performance of an actively quenched superconducting nanowire single photon detector and, in comparison to a passively quenched device, we predict roughly an order of magnitude improvement in the slew rate and peak voltage achieved in this configuration. The experimental performance of actively and passively quenched superconducting nanowire single photon detectors are then compared. It is shown that, in comparison to a passively quenched device, the actively quenched detectors simultaneously exhibited improved count rates, dark count rates, and timing jitter.

Impedance-matched differential superconducting nanowire detectors

“…Although we did not perform specific measurements to characterize this metric, we expect the count rate to be ultimately limited by the reset time of our detectors, approximately 160 ns. To address this issue, an active quenching circuit could be coupled to the device [39] and integrated on chip in future iterations.…”

Improved heralded single-photon source with a photon-number-resolving superconducting nanowire detector

“…Also, the detector reset time of nearly 100 ns restricts the maximum repetition rate of the source to be ∼ 10 MHz. An SNSPD with a reduced reset time based on a lower kinetic inductance nanowire material, or integrated with an active quenching circuit [57], would allow for high singlephoton generation rates. A multiplexing method based on multiple PNR SNPDSs would also support a high repetition rate.…”

Supporting quantum technologies with an ultralow-loss silicon photonics platform

“…Active electrical quenching has also been proposed but without dramatic improvements. 155 In order for the OEC speed to approach the SFQ speed, we are also exploring different multiplexing approaches, addressing arrays of SNSPDs instead of single detectors. In this approach, we avoid using the optical serializer at room temperature and replace it with an electrical serializer inside the cryostat, 156 resulting in major underexploitation of the fiber bandwidth.…”

“…A simple approach is to make the nanowire as short as possible, but experimental results clearly show that latching 152 – 154 becomes an issue in doing so. Active electrical quenching has also been proposed but without dramatic improvements 155 . In order for the OEC speed to approach the SFQ speed, we are also exploring different multiplexing approaches, addressing arrays of SNSPDs instead of single detectors.…”