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

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Fiber optic input and output for superconducting circuits

Lewis A. Bunz, Elie K. Track, Sergey V. Rylov, Fei-Yuh Perng, Jeffrey D. Morse

Published Jul 2, 1994• 16 citations
Publisher

Abstract

Superconducting devices operate at speeds where coaxial copper cables can be a limiting factor. Coaxial cables can limit frequency response and impose significant thermal loading on a cyrogenic system. The high bandwidth of optical fibers and their low thermal conductivity make them good candidates for providing data into and out of superconducting circuits. In this paper, we present the results of our experience in operating photodetectors and laser diodes together with superconducting circuits in the same low temperature (4.2 K) environment. Using these photodetectors, we demonstrate the input of optical signals to an analog superconducting circuit at 6 GHz. Output from a superconducting circuit operating at 500 MHz is fed into a laser diode, and optically coupled to room temperature electronics. By combining these two techniques, we demonstrate a fully operational superconducting shift register with both input and output signals supplied by optical fiber.

DOI
10.1117/12.181007

Related papers

An optically coupled superconducting analog to digital converter

Lewis A. Bunz, R. P. Robertazzi, Sergey V. Rylov

A superconducting analog-to-digital converter has been coupled with a laser diode also operating at 4.2 K to provide a serial output data stream via an optical fiber. The optical signal is converted to a room temperature electrical signal using standard optical fiber receiver techniques. After amplification these signals are fed into a fast comparator circuit. The output of the comparator is a TTL level signal suitable for connection to conventional electronic equipment.

IEEE Transactions on Applied Superconductivity•Jun 1, 1997•6 citations

Laser diodes for optical readout of cryo-electronics

Lewis A. Bunz, Sergey V. Rylov, Elie K. Track

We report successful coupling of electrical signals from low temperature (4.2 K) superconducting circuitry to room temperature electronics using laser diodes coupled to optical fibers. The techniques used rely on laser diodes operating at low temperatures, and on high gain amplifiers placed outside the low temperature environment. A new superconducting driver circuit is used to step-up the low output of these circuits to a seven millivolt level, sufficient to modulate the laser diodes. By properly choosing the laser source, the power dissipated within the cryogenic environment can be maintained below 400 (mu) W, with further improvements easily reached.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jun 23, 1994•4 citations

All-optical control and multiplexed readout of multiple superconducting qubits

Xiaoxuan Pan, Chuanlong Ma, Jia-Qi Wang +12 more

Superconducting quantum circuits operate at millikelvin temperatures, typically requiring independent microwave cables for each qubit for connecting room-temperature control and readout electronics. However, scaling to large-scale processors hosting hundreds of qubits faces a severe input/output (I/O) bottleneck, as the dense cable arrays impose prohibitive constraints on physical footprint, thermal load, wiring complexity, and cost. Here we demonstrate a complete optical I/O architecture for superconducting quantum circuits, in which all control and readout signals are transmitted exclusively via optical photons. Employing a broadband traveling-wave Brillouin microwave-to-optical transducer, we achieve simultaneous frequency-multiplexed optical readout of two qubits. Combined with fiber-integrated photodiode arrays for control signal delivery, this closed-loop optical I/O introduces no measurable degradation to qubit coherence times, with an optically driven single-qubit gate fidelity showing only a 0.19% reduction relative to standard microwave operation. These results establish optical interconnects as a viable path toward large-scale superconducting quantum processors, and open the possibility of networking multiple superconducting quantum computers housed in separate dilution refrigerators through a centralized room-temperature control infrastructure.

quant-pharXiv:2512.21199•Dec 25, 2025•0 citations

Characterizing All-Optical Biasing and Readout of a Superconducting Opto-Electronic Circuit

Frederik Thiele, Thomas R. Hummel, Julian Brockmeier +6 more

Superconducting nanowire single-photon detectors have become indispensable for experiments in quantum optics and photonic quantum information processing. Nevertheless, these detectors require temperatures below 4 K to operate. These devices typically require coaxial cables as electrical connections for biasing and readout. Replacing these electrical connections with optical fibers both isolates the SNSPD from noise in room-temperature control electronics and simultaneously achieves a connection with a low thermal load. Nevertheless, the optoelectronic interfaces required for this purpose must be fully compatible with the cryogenic operating conditions of the detector. Recently, optical readout of an SNSPD using an electro-optic modulator at cryogenic temperatures has been demonstrated [1]–[3]. In addition, we have shown an opto-electronic bias of an SNSPD by generating the bias current using a photodiode co-located on the cold stage of the cryostat [4]. Both methods replace elements of electrical connection for the SNSPD in the cryostat by an optical fiber. Here, we show the combination of the opto-electronic bias and optical read readout in a single device, which enables us to operate an SNSPD fully isolated from room temperature electronics.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 26, 2023•0 citations

Electro-Optical Control and Readout of Superconducting Devices

Calum Rose, Natale G. Pruiti, Daniel Kelly +3 more

Quantum computing is a rapidly evolving field with potential for solving complex problems beyond the reach of classical computers. Scalability in qubit design and signal processing architecture within cryostats is necessary for taking advantage of quantum computing's potential. Current state of the art qubit technology requires both a feed and readout line for each qubit within a quantum processor, with these lines generally being metallic coaxial cables. For stainless steel cables this represents a significant heat load into the cryostat. An alternative approach involves using optical fibers for signal transmission, as optical fibers have a thermal conductivity two orders of magnitude lower than stainless steel coaxial cables. The proposed method for optical signal transmission relies on electro-optic modulation, where a voltage applied to an electro-optic material changes its refractive index, allowing for a controllable phase change to be applied to any light passing through the material. This concept can be combined with on-chip photonic waveguide technology to build fiber-coupled phase modulators as well as intensity modulators using on chip interferometers. The proposed architecture uses a room temperature intensity modulator to encode microwave signals onto a laser signal, which is recovered at cryogenic temperatures using a photodiode and used as input for a device under test. The output of the test device is encoded onto light using a phase modulator and recovered at room temperature through interferometry. Proof-of-concept experiments have been carried out at room temperature, including noise characterization and preliminary tests of components at cryogenic temperatures.

IEEE International Conference on Quantum Computing and Engineering (QCE)•Sep 17, 2023•0 citations

Photonic readout of superconducting nanowire single photon counting detectors

Rajeev J. Ram, Marc de, Emma E. Wollman +1 more

Scalable, low power, high speed data transfer between cryogenic and room temperature environments is essential for the realization of practical, large-scale systems based on superconducting technologies. Optical fiber presents a 100–1,000x lower heat load than conventional electrical wiring, relaxing the requirements for thermal anchoring, and allows for very high bandwidth densities by carrying multiple signals through the same physical fiber. By operating a CMOS modulator in the forward bias regime at a temperature of 3.6 K, we have demonstrated the optical readout of a superconducting nanowire single-photon detector (SNSPD) without the need for an interfacing device.

Advanced Photon Counting Techniques•Jun 15, 2023•0 citations
Superconducting devices operate at speeds where coaxial copper cables can be a limiting factor. Coaxial cables can limit frequency response and impose significant thermal loading on a cyrogenic system. The high bandwidth of optical fibers and their low thermal conductivity make them good candidates for providing data into and out of superconducting circuits. In this paper, we present the results of our experience in operating photodetectors and laser diodes together with superconducting circuits in the same low temperature (4.2 K) environment. Using these photodetectors, we demonstrate the input of optical signals to an analog superconducting circuit at 6 GHz. Output from a superconducting circuit operating at 500 MHz is fed into a laser diode, and optically coupled to room temperature electronics. By combining these two techniques, we demonstrate a fully operational superconducting shift register with both input and output signals supplied by optical fiber.
We report successful coupling of electrical signals from low temperature (4.2 K) superconducting circuitry to room temperature electronics using laser diodes coupled to optical fibers. The techniques used rely on laser diodes operating at low temperatures, and on high gain amplifiers placed outside the low temperature environment. A new superconducting driver circuit is used to step-up the low output of these circuits to a seven millivolt level, sufficient to modulate the laser diodes. By properly choosing the laser source, the power dissipated within the cryogenic environment can be maintained below 400 (mu) W, with further improvements easily reached.
Superconducting quantum circuits operate at millikelvin temperatures, typically requiring independent microwave cables for each qubit for connecting room-temperature control and readout electronics. However, scaling to large-scale processors hosting hundreds of qubits faces a severe input/output (I/O) bottleneck, as the dense cable arrays impose prohibitive constraints on physical footprint, thermal load, wiring complexity, and cost. Here we demonstrate a complete optical I/O architecture for superconducting quantum circuits, in which all control and readout signals are transmitted exclusively via optical photons. Employing a broadband traveling-wave Brillouin microwave-to-optical transducer, we achieve simultaneous frequency-multiplexed optical readout of two qubits. Combined with fiber-integrated photodiode arrays for control signal delivery, this closed-loop optical I/O introduces no measurable degradation to qubit coherence times, with an optically driven single-qubit gate fidelity showing only a 0.19% reduction relative to standard microwave operation. These results establish optical interconnects as a viable path toward large-scale superconducting quantum processors, and open the possibility of networking multiple superconducting quantum computers housed in separate dilution refrigerators through a centralized room-temperature control infrastructure.
Superconducting nanowire single-photon detectors have become indispensable for experiments in quantum optics and photonic quantum information processing. Nevertheless, these detectors require temperatures below 4 K to operate. These devices typically require coaxial cables as electrical connections for biasing and readout. Replacing these electrical connections with optical fibers both isolates the SNSPD from noise in room-temperature control electronics and simultaneously achieves a connection with a low thermal load. Nevertheless, the optoelectronic interfaces required for this purpose must be fully compatible with the cryogenic operating conditions of the detector. Recently, optical readout of an SNSPD using an electro-optic modulator at cryogenic temperatures has been demonstrated [1]–[3]. In addition, we have shown an opto-electronic bias of an SNSPD by generating the bias current using a photodiode co-located on the cold stage of the cryostat [4]. Both methods replace elements of electrical connection for the SNSPD in the cryostat by an optical fiber. Here, we show the combination of the opto-electronic bias and optical read readout in a single device, which enables us to operate an SNSPD fully isolated from room temperature electronics.
Quantum computing is a rapidly evolving field with potential for solving complex problems beyond the reach of classical computers. Scalability in qubit design and signal processing architecture within cryostats is necessary for taking advantage of quantum computing's potential. Current state of the art qubit technology requires both a feed and readout line for each qubit within a quantum processor, with these lines generally being metallic coaxial cables. For stainless steel cables this represents a significant heat load into the cryostat. An alternative approach involves using optical fibers for signal transmission, as optical fibers have a thermal conductivity two orders of magnitude lower than stainless steel coaxial cables. The proposed method for optical signal transmission relies on electro-optic modulation, where a voltage applied to an electro-optic material changes its refractive index, allowing for a controllable phase change to be applied to any light passing through the material. This concept can be combined with on-chip photonic waveguide technology to build fiber-coupled phase modulators as well as intensity modulators using on chip interferometers. The proposed architecture uses a room temperature intensity modulator to encode microwave signals onto a laser signal, which is recovered at cryogenic temperatures using a photodiode and used as input for a device under test. The output of the test device is encoded onto light using a phase modulator and recovered at room temperature through interferometry. Proof-of-concept experiments have been carried out at room temperature, including noise characterization and preliminary tests of components at cryogenic temperatures.
Scalable, low power, high speed data transfer between cryogenic and room temperature environments is essential for the realization of practical, large-scale systems based on superconducting technologies. Optical fiber presents a 100–1,000x lower heat load than conventional electrical wiring, relaxing the requirements for thermal anchoring, and allows for very high bandwidth densities by carrying multiple signals through the same physical fiber. By operating a CMOS modulator in the forward bias regime at a temperature of 3.6 K, we have demonstrated the optical readout of a superconducting nanowire single-photon detector (SNSPD) without the need for an interfacing device.