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Study on integrated processes for SFQ circuits and superconducting nano-devices

Naoki Kondo, Kyosuke Sano, Tanaka Masamitu +3 more

The Japan Society of Applied PhysicsJul 10, 20190 citations

Superconducting single photon detectors integrated with single flux quantum readout circuits in a cryocooler

Shigehito Miki, Hirotaka Terai, Taro Yamashita +4 more

We report the operation of superconducting single photon detectors (SSPDs) with integrated readout electronics based on a single-flux-quantum (SFQ) circuit. The SSPDs were connected to a SFQ readout circuit without bias tee in a cryocooler system, and detection efficiencies (DEs) were measured to verify their correct operation. The DE curves matched well with those measured by conventional readout electronics, and the maximum bias current for normal operation was increased. In addition, we confirmed that the SFQ circuit correctly merged the input signals from two SSPDs. SSPDs with a SFQ readout circuit demonstrated a favorable timing jitter of 50 ps.We report the operation of superconducting single photon detectors (SSPDs) with integrated readout electronics based on a single-flux-quantum (SFQ) circuit. The SSPDs were connected to a SFQ readout circuit without bias tee in a cryocooler system, and detection efficiencies (DEs) were measured to verify their correct operation. The DE curves matched well with those measured by conventional readout electronics, and the maximum bias current for normal operation was increased. In addition, we confirmed that the SFQ circuit correctly merged the input signals from two SSPDs. SSPDs with a SFQ readout circuit demonstrated a favorable timing jitter of 50 ps.

Applied Physics LettersSep 12, 201155 citations

A New Nonlinearity for Superconducting Circuits

Marric Stephens

PhysicsSep 5, 20240 citations

Microbridge junctions for superconducting phase qubits

Martin P. Weides, Radoslaw C. Bialczak, M. Lenander +11 more

Bulletin of the American Physical SocietyMar 17, 20100 citations

40 Gbit/s operation of superconductive single flux quantum digital integrated circuit with optical data input

Y. Hashimoto, Hideo Suzuki, Michitaka Maruyama +2 more

A superconductive single flux quantum (SFQ) digital integrated circuit with an optical data input has been demonstrated at the system level of 40 Gbit/s for the first time. A uni travelling carrier photodiode (UTC-PD) and an SFQ circuit chip, on which 40 Gbit/s I/O interfaces were integrated, were packaged on a cold stage (4–6 K) of a cryocooler system. The UTC-PD's output was connected to an input port of the SFQ circuit with a Cu coaxial cable. From room temperature, a 40 GHz clock was supplied to the SFQ circuit while 40 Gbit/s optical data were supplied to the UTC-PD. The SFQ circuit operated correctly with the optical 40 Gbit/s data. The measured bit error rate was less than 10−13 for 1.2 mW optical PRBS 7 input at 40 Gbit/s.A superconductive single flux quantum (SFQ) digital integrated circuit with an optical data input has been demonstrated at the system level of 40 Gbit/s for the first time. A uni travelling carrier photodiode (UTC-PD) and an SFQ circuit chip, on which 40 Gbit/s I/O interfaces were integrated, were packaged on a cold stage (4–6 K) of a cryocooler system. The UTC-PD's output was connected to an input port of the SFQ circuit with a Cu coaxial cable. From room temperature, a 40 GHz clock was supplied to the SFQ circuit while 40 Gbit/s optical data were supplied to the UTC-PD. The SFQ circuit operated correctly with the optical 40 Gbit/s data. The measured bit error rate was less than 10−13 for 1.2 mW optical PRBS 7 input at 40 Gbit/s.

Electronics LettersDec 23, 200810 citations

Sub-Kelvin single flux quantum control circuits and multi-chip packaging for supporting superconducting qubit

Shinichi Yorozu, Toshiyuki Miyazaki, Vasili K. Semenov +6 more

Superconducting single flux quantum (SFQ) circuit can operate at very low temperature. This is suitable for controlling a quantum computing system with Josephson junctions. However, it is difficult to integrate both SFQ circuits and qubits into a single-chip, because of the dissipative characteristics of SFQ circuits. Therefore, we have developed a multi-chip packaging technology for a qubit control module. The module consists of SFQ circuit chips, qubit chips, and a substrate all of which are fabricated with Nb and Al technology. The chips are flip-chip bonded with superconducting solder bumps. We also investigated SFQ control circuits for superconducting qubits and circuit parameter optimization for sub-Kelvin temperature operation. Using both multi-chip packaging and optimized SFQ control circuit makes the design of qubit control module more flexible.Superconducting single flux quantum (SFQ) circuit can operate at very low temperature. This is suitable for controlling a quantum computing system with Josephson junctions. However, it is difficult to integrate both SFQ circuits and qubits into a single-chip, because of the dissipative characteristics of SFQ circuits. Therefore, we have developed a multi-chip packaging technology for a qubit control module. The module consists of SFQ circuit chips, qubit chips, and a substrate all of which are fabricated with Nb and Al technology. The chips are flip-chip bonded with superconducting solder bumps. We also investigated SFQ control circuits for superconducting qubits and circuit parameter optimization for sub-Kelvin temperature operation. Using both multi-chip packaging and optimized SFQ control circuit makes the design of qubit control module more flexible.

Journal of Physics Conference SeriesJun 1, 20063 citations

Analysis of a superconducting microbridge integrated with an SFQ circuit

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