Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Transactions on Applied Superconductivity

Superconductive Three-Terminal Amplifier/Discriminator

Orlando Quaranta, S. Marchetti, Nadia Martucciello, S. Pagano, Mikkel Ejrnaes, Roberto Cristiano, Ciro Nappi

Published Jun 1, 2009• 12 citations
Publisher

Abstract

We describe a new superconductive three-terminal device that acts as a fast pulse amplifier and discriminator. The device is based on a parallel nano-wire configuration. The nano-wires are properly biased near their critical current. When a current pulse of sufficient amplitude is injected into one of the wires, a transition to the normal state of all the wires occurs, thus generating a large output current pulse. This device could be used as a pulse amplifier for signals generated by nano-wire detectors or by RSFQ circuits. The parallel nano-wire structure can be realized with the same fabrication process used for NbN Superconducting Single Photon Detector (SSPD), so its integration into the existing technology is straightforward. Here we present numerical simulations of the device, with special attention to circuit requirement for the correct operation.

DOI
10.1109/tasc.2009.2017952

Related papers

Nano-Strip Three-Terminal Superconducting Device for Cryogenic Detector Readout

S. Pagano, Nadia Martucciello, Roberto Cristiano +7 more

A superconducting 3-terminal device based on NbN ultra-thin nano-strips has been realized. The device is capable of pulse discrimination and shaping and provides power gain with standard 50 Ω input and output impedance. It operates at 4.2 K and is well suited for the realization of output interfaces for superconducting digital circuits and as readout of cryogenic detectors. Successful realization of the integrated readout of a nano-strip single photon detectors is reported.

IEEE Transactions on Applied Superconductivity•Nov 10, 2010•11 citations

Characterization of superconducting pulse discriminators based on parallel NbN nanostriplines

Mikkel Ejrnaes, A. Casaburi, Roberto Cristiano +6 more

A superconducting pulse discriminator based on a cascade switch to the normal state of parallel ultrathin NbN nanostrips has been fabricated and carefully investigated. Correct operation was achieved using 1 ns input pulses with amplitudes down to 15 µA. The discriminator had a peak current gain of 12 and an FWHM timing jitter of 80 ps, limited by our measurement instrument resolution. These characteristics, together with simple on-chip integration, small area and low dissipation, make this device suitable for applications such as readout of fast cryogenic detectors and the output stage of superconducting digital circuits.

Superconductor Science and Technology•Jan 20, 2011•9 citations

A cascade switching superconducting single photon detector

Mikkel Ejrnaes, Roberto Cristiano, Orlando Quaranta +6 more

We have realized superconducting single photon detectors with reduced inductance and increased signal pulse amplitude. The detectors are based on a parallel connection of ultrathin NbN nanowires with a common bias inductance. When properly biased, an absorbed photon induces a cascade switch of all the parallel wires generating a signal pulse amplitude of 2mV. The parallel wire configuration lowers the detector inductance and reduces the response time well below 1ns.

Applied Physics Letters•Dec 24, 2007•124 citations

Superconducting single photon detectors based on parallel NbN nanowires

Mikkel Ejrnaes, A. Casaburi, S. Pagano +4 more

Ultrathin NbN nanowires is the material of choice for superconducting single photon detectors (SSPD) due to the good efficiency, dark count rate and timing jitter at 1550 nm wavelength obtained. These performance parameters are achieved using nanowires a few nanometers thick and 100 nm wide patterned into a meander shape in order to achieve area coverage. The meander shape effectively makes the SSPD of a single very long nanowire in turn giving it a significant inductance which limits the maximum count rate of the detector. Recently, we demonstrated how one can exploit a cascade switch to the normal state of nanowires connected in parallel to significantly reduce the SSPD inductance and increase the signal amplitude. Here we present how one can configure SSPDs that uses multiple cascade switches to the normal state. We show how this principle can be used to expand the SSPD coverage area with a very limited increase in detector inductance with area. Finally we discuss our first results obtained with SSPD based on the multiple cascade switch principle, showing correct operation, increased operational bias range and increased signal pulse amplitudes.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 29, 2011•0 citations

Readout Electronics Using Single-Flux-Quantum Circuit Technology for Superconducting Single-Photon Detector Array

Hirotaka Terai, Shigehito Miki, Zhen Wang

Superconducting single-photon detectors (SSPDs) based on NbN nanowires possess properties such as high counting rate, low dark count rate and small timing jitter, which are promising characteristics for a quantum key distribution system. An SSPD array has recently attracted attention, because it can provide a higher counting rate, and spatial and photon-number resolutions. We propose readout electronics using single-flux-quantum (SFQ) circuits to process a large number of output signals from an SSPD array. We designed and tested an interface circuit between an SSPD and SFQ circuit, and successfully observed SFQ pulse generation for an input pulse with a current amplitude of 17.4 ~ 36.4 muA , which is comparable with an output current amplitude of the SSPD. The interface circuit was also operational for an input pulse duration of 1.6 ns, which is shorter than the typical recovery time of the SSPD.

IEEE Transactions on Applied Superconductivity•Jun 1, 2009•63 citations

Experimental characterization of NbN nanowire optical detectors with parallel stripline configuration

A. Casaburi, Mikkel Ejrnaes, Orlando Quaranta +10 more

We have developed a novel geometrical configuration for NbN-based superconducting single photon optical detector (SSPD) that achieves two goals: a much lower intrinsic impedance, and a consequently greater bandwidth, and a much larger signal amplitude compared to the standard meandered configuration. This has been obtained by implementing a properly designed parallel stripline structure where a cascade switching mechanism occurs when one of the striplines is hit by an optical photon. The overall switching occurs synchronously and in a very short time, giving rise to a strong and fast voltage pulse. The SSPD have been realized using state of the art NbN deposition technology and e-beam lithography. The strips are 100 nm wide and 5 μm long and have been realized with 4 nm NbN film on sapphire and Si substrate. We report on experimental characterization of such novel devices. The performances of the proposed novel type of SSPD are compared with standard SSPD design and results in terms of signal amplitude, risetime and effective detection area.

Journal of Physics Conference Series•Feb 1, 2008•1 citation
We describe a new superconductive three-terminal device that acts as a fast pulse amplifier and discriminator. The device is based on a parallel nano-wire configuration. The nano-wires are properly biased near their critical current. When a current pulse of sufficient amplitude is injected into one of the wires, a transition to the normal state of all the wires occurs, thus generating a large output current pulse. This device could be used as a pulse amplifier for signals generated by nano-wire detectors or by RSFQ circuits. The parallel nano-wire structure can be realized with the same fabrication process used for NbN Superconducting Single Photon Detector (SSPD), so its integration into the existing technology is straightforward. Here we present numerical simulations of the device, with special attention to circuit requirement for the correct operation.
A superconducting pulse discriminator based on a cascade switch to the normal state of parallel ultrathin NbN nanostrips has been fabricated and carefully investigated. Correct operation was achieved using 1 ns input pulses with amplitudes down to 15 µA. The discriminator had a peak current gain of 12 and an FWHM timing jitter of 80 ps, limited by our measurement instrument resolution. These characteristics, together with simple on-chip integration, small area and low dissipation, make this device suitable for applications such as readout of fast cryogenic detectors and the output stage of superconducting digital circuits.
Ultrathin NbN nanowires is the material of choice for superconducting single photon detectors (SSPD) due to the good efficiency, dark count rate and timing jitter at 1550 nm wavelength obtained. These performance parameters are achieved using nanowires a few nanometers thick and 100 nm wide patterned into a meander shape in order to achieve area coverage. The meander shape effectively makes the SSPD of a single very long nanowire in turn giving it a significant inductance which limits the maximum count rate of the detector. Recently, we demonstrated how one can exploit a cascade switch to the normal state of nanowires connected in parallel to significantly reduce the SSPD inductance and increase the signal amplitude. Here we present how one can configure SSPDs that uses multiple cascade switches to the normal state. We show how this principle can be used to expand the SSPD coverage area with a very limited increase in detector inductance with area. Finally we discuss our first results obtained with SSPD based on the multiple cascade switch principle, showing correct operation, increased operational bias range and increased signal pulse amplitudes.
Superconducting single-photon detectors (SSPDs) based on NbN nanowires possess properties such as high counting rate, low dark count rate and small timing jitter, which are promising characteristics for a quantum key distribution system. An SSPD array has recently attracted attention, because it can provide a higher counting rate, and spatial and photon-number resolutions. We propose readout electronics using single-flux-quantum (SFQ) circuits to process a large number of output signals from an SSPD array. We designed and tested an interface circuit between an SSPD and SFQ circuit, and successfully observed SFQ pulse generation for an input pulse with a current amplitude of 17.4 ~ 36.4 muA , which is comparable with an output current amplitude of the SSPD. The interface circuit was also operational for an input pulse duration of 1.6 ns, which is shorter than the typical recovery time of the SSPD.
We have developed a novel geometrical configuration for NbN-based superconducting single photon optical detector (SSPD) that achieves two goals: a much lower intrinsic impedance, and a consequently greater bandwidth, and a much larger signal amplitude compared to the standard meandered configuration. This has been obtained by implementing a properly designed parallel stripline structure where a cascade switching mechanism occurs when one of the striplines is hit by an optical photon. The overall switching occurs synchronously and in a very short time, giving rise to a strong and fast voltage pulse. The SSPD have been realized using state of the art NbN deposition technology and e-beam lithography. The strips are 100 nm wide and 5 μm long and have been realized with 4 nm NbN film on sapphire and Si substrate. We report on experimental characterization of such novel devices. The performances of the proposed novel type of SSPD are compared with standard SSPD design and results in terms of signal amplitude, risetime and effective detection area.