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

Ultrafast, integrable, optics-based interface between superconducting and room-temperature electronics

Chia-Chi Wang, Marc Currie, T.Y. Hsiang

Published Jun 1, 1995• 5 citations
Publisher

Abstract

An ultrafast optical interface between superconducting and room-temperature electronics is proposed to take full advantage of high-speed superconducting circuits. We report on the computed and experimental studies of an optical receiving and modulating system that is compatible in processing with the prevailing integrated-superconducting-circuit technology. Planar interdigitated Nb/Si/Nb metal-semiconductor-metal (MSM) photodiodes are demonstrated as optical receivers with resolvable bit-rate as high as 38 Gb/s, and the response of MSM diode was shaped to be a single-flux-quantum pulse to drive Josephson-junction-based circuits. A similar interdigitated structure on a silicon waveguide is proposed to be an ultrafast light-intensity modulator, with its operation based on carrier-density modulation of the optical index of refraction. This field-effect device has insignificant power dissipation, in addition to high speed. A sample modulator with 5-V bias is shown to have a modulation depth of 40% and a bandwidth over 70 GHz.>

DOI
10.1109/77.403261

Related papers

Optical data communication between Josephson-junction circuits and room-temperature electronics

Bart Van Zeghbroeck

The feasibility of optical data transmission to and from Josephson junction circuits, using metal-semiconductor-metal (MSM) photodiodes and GaAs/AlGaAs semiconductor laser diodes with sub-mA threshold current, is demonstrated. Standard devices can be used with the exception of a cooled GaAs detector. It is shown that silicon MSM detectors compatible with Josephson junction circuits can be fabricated. While these detectors show large photoconductive effects at room temperature they behave as good-quality photodiodes at low temperatures. Power dissipation in the laser diode scales with temperature while maintaining the modulation frequency. It is also shown that the combination of a laser diode and a photodiode provides the voltage gain needed to interface Josephson-junction circuits with room-temperature electronics. Experimental results on MSM detectors and laser diodes are presented. Expected power dissipation is below 1 mW per input/output (I/O) at a data rate of 1 Gb/s.>

IEEE Transactions on Applied Superconductivity•Mar 1, 1993•15 citations

Magneto-optical modulator for the superconducting digital output interface

Roberto Rey-de-Castro

Josephson-junction-based low temperature rapid single flux quantum (RSFQ) superconducting electronics is already a mature technology, which is expected to perform at speeds exceeding 100 GHz [1]. However, the RSFQ technology still lacks a fast enough output interface between its operating circuit temperature T = 4.2 K and the room temperature electronic environment. RSFQ circuits work at liquid helium temperatures and the direct interconnection of these circuits and room temperature circuits using, e.g., copper transmission lines would consume too much of the cooling power [2]. To solve this problem a magneto-optical (MO) output interface has been proposed [3], in which the output current pulse from the RSFQ circuit is converted into an optical pulse and delivered to room temperature readout circuitry via an optical fiber.

Opto-Canada: SPIE Regional Meeting on Optoelectronics, Photonics, and Imaging•Aug 29, 2017•1 citation

Optoelectronic clocking system for testing RSFQ circuits up to 20 GHz

J.F. Buzacchelli, Hae-Seung Lee, Sotiris Alexandrou +2 more

Unlike coaxial cable, optical fiber has a bandwidth commensurate with the clock rates of even the fastest rapid single flux quantum (RSFQ) circuits. Employing this advantage, we have developed an optoelectronic clocking system, in which optical pulses from a picosecond laser are delivered via fiber to a superconducting chip, on which metal-semiconductor-metal (MSM) photodiodes generate fast electrical pulses with subpicosecond timing accuracy. An optical pulse splitter, constructed out of beamsplitters, mirrors, and half-wave plates, permits selection of pulse pattern and clock rate from 80.6 MHz up to 20.6 GHz. With a sampling oscilloscope, we have directly observed optical triggering of an RSFQ T flip-flop at frequencies up to 1.3 GHz with a variety of bit patterns. Optical triggering of a Josephson transmission line (JTL) at frequencies up to 20.6 GHz has been verified by precise measurement of the Josephson voltage; this result represents the highest clock rate ever reported for an optical interface for RSFQ circuits.

IEEE Transactions on Applied Superconductivity•Jun 1, 1997•22 citations

Ultrafast superconducting optoelectronics

Roman Sobolewski

Ultrafast phenomena, optoelectronics, and superconductivity are acknowledged fields of technological importance and a very large amount of research has been performed in these areas in recent years. In modern, highly-advanced digital electronic circuits, the primary function of high-performance, high-speed signal processing is given to superconducting single-flux-quantum (SFQ) logical devices, based on resistively-shunted Josephson tunnel junctions. The development of this branch of digital electronics requires ultrafast, and ultra sensitive optical-to-electrical transducers for fiber optic interconnects, which must be able to transform to the electrical domain the input information coded in the form of a train of ultrafast optical pulses and, subsequently, feed it into the SFQ processor.

IEEE Lasers and Electro-Optics Society Annual Meeting (LEOS)•Jan 20, 2003•5 citations

Broadband interfacing of superconducting digital systems to room temperature electronics

D.F. Schneider, J.C. Lin, Stanislav V. Polonsky +2 more

We have developed and tested simple and inexpensive electronics for interfacing Rapid Single-Flux-Quantum (RSFQ) Josephson-junction circuits to room temperature digital systems. Voltage-level (Non-Return-to-Zero) bit signals with a swing of /spl sim/150 uV, developed on-chip by standard SFQ/DC converters, and in some cases amplified to 1.5 mV swing by HUFFLE-type circuits, are passed to the 300 K environment using a high density (40 channel) flexible coplanar waveguide assembly. AC-coupled, 2-3 stage microwave Si-bipolar amps, and Emitter-Coupled-Logic (ECL) buffers accomplish voltage level translation to the standard ECL levels, Using this technique, data rates in excess of 1 Gb/s per channel can be achieved at low cost per channel,.>

IEEE Transactions on Applied Superconductivity•Jun 1, 1995•29 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
An ultrafast optical interface between superconducting and room-temperature electronics is proposed to take full advantage of high-speed superconducting circuits. We report on the computed and experimental studies of an optical receiving and modulating system that is compatible in processing with the prevailing integrated-superconducting-circuit technology. Planar interdigitated Nb/Si/Nb metal-semiconductor-metal (MSM) photodiodes are demonstrated as optical receivers with resolvable bit-rate as high as 38 Gb/s, and the response of MSM diode was shaped to be a single-flux-quantum pulse to drive Josephson-junction-based circuits. A similar interdigitated structure on a silicon waveguide is proposed to be an ultrafast light-intensity modulator, with its operation based on carrier-density modulation of the optical index of refraction. This field-effect device has insignificant power dissipation, in addition to high speed. A sample modulator with 5-V bias is shown to have a modulation depth of 40% and a bandwidth over 70 GHz.>
The feasibility of optical data transmission to and from Josephson junction circuits, using metal-semiconductor-metal (MSM) photodiodes and GaAs/AlGaAs semiconductor laser diodes with sub-mA threshold current, is demonstrated. Standard devices can be used with the exception of a cooled GaAs detector. It is shown that silicon MSM detectors compatible with Josephson junction circuits can be fabricated. While these detectors show large photoconductive effects at room temperature they behave as good-quality photodiodes at low temperatures. Power dissipation in the laser diode scales with temperature while maintaining the modulation frequency. It is also shown that the combination of a laser diode and a photodiode provides the voltage gain needed to interface Josephson-junction circuits with room-temperature electronics. Experimental results on MSM detectors and laser diodes are presented. Expected power dissipation is below 1 mW per input/output (I/O) at a data rate of 1 Gb/s.>
Josephson-junction-based low temperature rapid single flux quantum (RSFQ) superconducting electronics is already a mature technology, which is expected to perform at speeds exceeding 100 GHz [1]. However, the RSFQ technology still lacks a fast enough output interface between its operating circuit temperature T = 4.2 K and the room temperature electronic environment. RSFQ circuits work at liquid helium temperatures and the direct interconnection of these circuits and room temperature circuits using, e.g., copper transmission lines would consume too much of the cooling power [2]. To solve this problem a magneto-optical (MO) output interface has been proposed [3], in which the output current pulse from the RSFQ circuit is converted into an optical pulse and delivered to room temperature readout circuitry via an optical fiber.
Unlike coaxial cable, optical fiber has a bandwidth commensurate with the clock rates of even the fastest rapid single flux quantum (RSFQ) circuits. Employing this advantage, we have developed an optoelectronic clocking system, in which optical pulses from a picosecond laser are delivered via fiber to a superconducting chip, on which metal-semiconductor-metal (MSM) photodiodes generate fast electrical pulses with subpicosecond timing accuracy. An optical pulse splitter, constructed out of beamsplitters, mirrors, and half-wave plates, permits selection of pulse pattern and clock rate from 80.6 MHz up to 20.6 GHz. With a sampling oscilloscope, we have directly observed optical triggering of an RSFQ T flip-flop at frequencies up to 1.3 GHz with a variety of bit patterns. Optical triggering of a Josephson transmission line (JTL) at frequencies up to 20.6 GHz has been verified by precise measurement of the Josephson voltage; this result represents the highest clock rate ever reported for an optical interface for RSFQ circuits.
Ultrafast phenomena, optoelectronics, and superconductivity are acknowledged fields of technological importance and a very large amount of research has been performed in these areas in recent years. In modern, highly-advanced digital electronic circuits, the primary function of high-performance, high-speed signal processing is given to superconducting single-flux-quantum (SFQ) logical devices, based on resistively-shunted Josephson tunnel junctions. The development of this branch of digital electronics requires ultrafast, and ultra sensitive optical-to-electrical transducers for fiber optic interconnects, which must be able to transform to the electrical domain the input information coded in the form of a train of ultrafast optical pulses and, subsequently, feed it into the SFQ processor.
We have developed and tested simple and inexpensive electronics for interfacing Rapid Single-Flux-Quantum (RSFQ) Josephson-junction circuits to room temperature digital systems. Voltage-level (Non-Return-to-Zero) bit signals with a swing of /spl sim/150 uV, developed on-chip by standard SFQ/DC converters, and in some cases amplified to 1.5 mV swing by HUFFLE-type circuits, are passed to the 300 K environment using a high density (40 channel) flexible coplanar waveguide assembly. AC-coupled, 2-3 stage microwave Si-bipolar amps, and Emitter-Coupled-Logic (ECL) buffers accomplish voltage level translation to the standard ECL levels, Using this technique, data rates in excess of 1 Gb/s per channel can be achieved at low cost per channel,.>
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.