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

Multiplexing Techniques of Single Flux Quantum Circuit Based Readout Circuit for a Multi-Channel Sensing System

Kenta Aoki, Yuki Yamanashi, Nobuyuki Yoshikawa

Published Nov 28, 2012• 7 citations
Publisher

Abstract

Time division multiplexing (TDM) and code division multiplexing (CDM) have been investigated for multichannel superconductive sensing systems using single-flux-quantum (SFQ) readout circuits. Output data from a superconductive sensor array can be multiplexed using SFQ binary counters, which count the number of SFQ pulses from each sensor, and are transmitted from a low-temperature environment to a room-temperature equipment using a small number of lines. We have estimated and compared the performance of a multichannel superconductive sensing system that employs TDM and CDM on the basis of analog circuit simulation and circuit design results. TDM is useful for reducing the number of lines, but the slew rate of the sensing system decreases with an increase in the number of channels. On the other hand, in the case of CDM, the slew rate of the system does not decrease with an increase in the number of channels. We have designed and tested a 2-channel digital superconducting quantum interference device system that can perform TDM and CDM employing SFQ up/down binary counters. In both circuits, the 16 Φ0input waveforms were reconstructed from the measured data, with an error of less than the flux quantum Φ0.

DOI
10.1109/tasc.2012.2230679

Related papers

SFQ Multiplexed Signal Processing Circuits for STJ Photon Detector Arrays

Hiroaki Myoren, Yu Yoshizawa, Tohru Taino

We have been studying single flux quantum (SFQ) digital signal processing (DSP) circuits for superconducting tunnel junction (STJ) photon detector arrays. The proposed DSP circuit consists of a binary tree of multiplexers, a time counter, a binary counter, and a readout memory. Each multiplexer was designed such that the first arriving SFQ pulse train connects to the binary counter until the time counter reaches a set value. The time counter is set to a sufficiently long time compared with the response time of STJ photon detector. After processing the multiplexer, SFQ pulses are integrated by the binary counter. The number of integrated SFQ pulses is proportional to the number of quasi-particles generated by photon irradiation in an STJ. After the time counter reaches the set value, the time counter generates a set SFQ pulse to set the multiplexer in the ready state, the integrated value is sent to the readout memory and then the binary counter is reset. The binary tree of multiplexers could be extended to have address bits for photon imaging using an STJ array. One key component of the proposed DSP circuit was fabricated and its operation using an on-chip clock generator was successfully demonstrated.

IEEE Transactions on Applied Superconductivity•Jun 1, 2009•4 citations

Code-division SQUID multiplexing

Michael D. Niemack, Joern Beyer, Hsiao-Mei Cho +7 more

Multiplexed superconducting quantum interference device (SQUID) readout systems are critical for measuring large arrays of superconducting transition-edge sensors (TES). We demonstrate a code-division SQUID multiplexing (CDM) architecture that is modulated by Walsh codes. Measurements and simulations of a prototype multiplexer show that this modulation scheme is not degraded by SQUID-noise aliasing, suppresses parasitic pickup, and has low levels of crosstalk. These properties enable this architecture to scale to large TES arrays. Furthermore, CDM modulation suppresses the 1/f knee in the noise to below 20 mHz, suggesting the use of this circuit for low-frequency-noise mitigation in more general SQUID applications.

Applied Physics Letters•Apr 19, 2010•37 citations

Time-division superconducting quantum interference device multiplexer for transition-edge sensors

Piet A. J. de Korte, Joern Beyer, Steven W. Deiker +7 more

We report on the design and performance of our second-generation 32-channel time-division multiplexer developed for the readout of large-format arrays of superconducting transition-edge sensors. We present design issues and measurement results on its gain, bandwidth, noise, and cross talk. In particular, we discuss noise performance at low frequency, important for long uninterrupted submillimeter/far-infrared observations, and present a scheme for mitigation of low-frequency noise. Also, results are presented on the decoupling of the input circuit from the first-stage feedback signal by means of a balanced superconducting quantum interference device pair. Finally, the first results of multiplexing several input channels in a switched, digital flux-lock loop are shown.

Review of Scientific Instruments•Jul 23, 2003•177 citations

Single-Flux-Quantum Circuit Based Readout System for Detector Arrays by Using Time to Digital Conversion

Ali Bozbey, Shigeyuki Miyajima, Hiroyuki Akaike +1 more

We propose a single-flux-quantum (SFQ) based readout circuit for a transition edge sensor (TES) array for X-ray radiation detection. Utilization of SFQ circuits for this purpose enables large-scale integration of TESs due to very high speed processing ability of the received signals and using an already established integrated circuit design environment. We utilize the cooling time dependence of the TES on the incident X-ray energy. Time to digital conversion is made by using an SFQ based quasi-one-junction SQUID (QOS), which works as a 1-bit comparator with an adjustable current threshold level, and an SFQ based high speed counter. The readout system is composed of two separate chips that are connected to each other with flexible superconducting wiring. The QOS-multiplexer chip is directly connected to the TES array and it performs the digital conversion of the TES output. The demultiplexer-counter chip, which will be placed at elevated temperatures, receives the multiplexed SFQ pulses and determines the duration of the TES output which is above the predetermined threshold level. Final goal of this work is to readout more than 10 k TES pixels and in this paper, feasibility of the system and current status of the development process is demonstrated.

IEEE Transactions on Applied Superconductivity•Jun 1, 2009•27 citations

Frequency division multiplexing readout and simultaneous manipulation of an array of flux qubits

Markus Jerger, Stefano Poletto, P. Macha +3 more

An important desired ingredient of superconducting quantum circuits is a readout scheme whose complexity does not increase with the number of qubits involved in the measurement. Here, we present a readout scheme employing a single microwave line, which enables simultaneous readout of multiple qubits. Consequently, scaling up superconducting qubit circuits is no longer limited by the readout apparatus. Parallel readout of 6 flux qubits using a frequency division multiplexing technique is demonstrated, as well as simultaneous manipulation and time resolved measurement of 3 qubits. We discuss how this technique can be scaled up to read out hundreds of qubits on a chip.

arXiv:1205.6375•Applied Physics Letters•Jul 23, 2012•98 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
Time division multiplexing (TDM) and code division multiplexing (CDM) have been investigated for multichannel superconductive sensing systems using single-flux-quantum (SFQ) readout circuits. Output data from a superconductive sensor array can be multiplexed using SFQ binary counters, which count the number of SFQ pulses from each sensor, and are transmitted from a low-temperature environment to a room-temperature equipment using a small number of lines. We have estimated and compared the performance of a multichannel superconductive sensing system that employs TDM and CDM on the basis of analog circuit simulation and circuit design results. TDM is useful for reducing the number of lines, but the slew rate of the sensing system decreases with an increase in the number of channels. On the other hand, in the case of CDM, the slew rate of the system does not decrease with an increase in the number of channels. We have designed and tested a 2-channel digital superconducting quantum interference device system that can perform TDM and CDM employing SFQ up/down binary counters. In both circuits, the 16 Φ0input waveforms were reconstructed from the measured data, with an error of less than the flux quantum Φ0.
We have been studying single flux quantum (SFQ) digital signal processing (DSP) circuits for superconducting tunnel junction (STJ) photon detector arrays. The proposed DSP circuit consists of a binary tree of multiplexers, a time counter, a binary counter, and a readout memory. Each multiplexer was designed such that the first arriving SFQ pulse train connects to the binary counter until the time counter reaches a set value. The time counter is set to a sufficiently long time compared with the response time of STJ photon detector. After processing the multiplexer, SFQ pulses are integrated by the binary counter. The number of integrated SFQ pulses is proportional to the number of quasi-particles generated by photon irradiation in an STJ. After the time counter reaches the set value, the time counter generates a set SFQ pulse to set the multiplexer in the ready state, the integrated value is sent to the readout memory and then the binary counter is reset. The binary tree of multiplexers could be extended to have address bits for photon imaging using an STJ array. One key component of the proposed DSP circuit was fabricated and its operation using an on-chip clock generator was successfully demonstrated.
Multiplexed superconducting quantum interference device (SQUID) readout systems are critical for measuring large arrays of superconducting transition-edge sensors (TES). We demonstrate a code-division SQUID multiplexing (CDM) architecture that is modulated by Walsh codes. Measurements and simulations of a prototype multiplexer show that this modulation scheme is not degraded by SQUID-noise aliasing, suppresses parasitic pickup, and has low levels of crosstalk. These properties enable this architecture to scale to large TES arrays. Furthermore, CDM modulation suppresses the 1/f knee in the noise to below 20 mHz, suggesting the use of this circuit for low-frequency-noise mitigation in more general SQUID applications.
We report on the design and performance of our second-generation 32-channel time-division multiplexer developed for the readout of large-format arrays of superconducting transition-edge sensors. We present design issues and measurement results on its gain, bandwidth, noise, and cross talk. In particular, we discuss noise performance at low frequency, important for long uninterrupted submillimeter/far-infrared observations, and present a scheme for mitigation of low-frequency noise. Also, results are presented on the decoupling of the input circuit from the first-stage feedback signal by means of a balanced superconducting quantum interference device pair. Finally, the first results of multiplexing several input channels in a switched, digital flux-lock loop are shown.
We propose a single-flux-quantum (SFQ) based readout circuit for a transition edge sensor (TES) array for X-ray radiation detection. Utilization of SFQ circuits for this purpose enables large-scale integration of TESs due to very high speed processing ability of the received signals and using an already established integrated circuit design environment. We utilize the cooling time dependence of the TES on the incident X-ray energy. Time to digital conversion is made by using an SFQ based quasi-one-junction SQUID (QOS), which works as a 1-bit comparator with an adjustable current threshold level, and an SFQ based high speed counter. The readout system is composed of two separate chips that are connected to each other with flexible superconducting wiring. The QOS-multiplexer chip is directly connected to the TES array and it performs the digital conversion of the TES output. The demultiplexer-counter chip, which will be placed at elevated temperatures, receives the multiplexed SFQ pulses and determines the duration of the TES output which is above the predetermined threshold level. Final goal of this work is to readout more than 10 k TES pixels and in this paper, feasibility of the system and current status of the development process is demonstrated.
An important desired ingredient of superconducting quantum circuits is a readout scheme whose complexity does not increase with the number of qubits involved in the measurement. Here, we present a readout scheme employing a single microwave line, which enables simultaneous readout of multiple qubits. Consequently, scaling up superconducting qubit circuits is no longer limited by the readout apparatus. Parallel readout of 6 flux qubits using a frequency division multiplexing technique is demonstrated, as well as simultaneous manipulation and time resolved measurement of 3 qubits. We discuss how this technique can be scaled up to read out hundreds of qubits on a chip.
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.