---
OA_place: publisher
_id: '21863'
abstract:
- lang: eng
  text: "Atoms and photons, two things so different but yet so alike. The former,
    the building block of matter, something we learn about in school and imagine it
    as some tiny marbles encircled by other tinier marbles. The latter, an electromagnetic
    wave, a light particle or an excitation of the electromagnetic field. Quantum
    mechanics tells us about the properties of these two entities. And even if it
    sounds, looks and writes counter-intuitive, it has proven right for over a century
    now.\r\n\r\nIn this work, I elaborate on how we tested the laws of quantum mechanics
    and how we used them learn more about the tiny building blocks of nature and the
    fields they use to talk to each other. The atoms we use, are artificial. Superconducting
    qubits, small electrical circuits with quantized energy levels behave like electrons
    that transition between different orbitals in an atom. One of the qubits' advantages,
    is also a big disadvantage. We design the circuits' energy levels and fabricate
    them in a cleanroom. This allows for arbitrary spaced energy levels but in contrast
    to real atoms, prevents two superconducting qubits from being alike. Still, this
    qubit platform is one of the frontrunners for future quantum computing technology
    and testing fundamental physics due to their scalability.\r\n\r\nWe interface
    superconducting qubits, which operate in the GHz regime, with microwave photons.
    We use 3D aluminum cavities as mediators between qubits and photons. The cavities
    allow for non-destructive readout of the qubit state, they shield the qubits from
    noise at the qubit frequency and they give us an easy way to frequency-tune these
    joint systems.\r\n\r\nWe need to operate superconducting qubits and their cavities
    at millikelvin temperatures in dilution refrigerators. At higher temperatures,
    superconductivity suffers and even worse, the environment is filled with thermal
    noise photons. This poses a fundamental limitation on the scalability of superconducting
    qubit devices. Also connecting multiple devices in different fridges does not
    work over room temperature links because the microwave photons used for this purpose
    will be covered in noise and the quantum information they carry, will be unusable.\r\n\r\nInfrared
    photons do not suffer from this noise problem since there are close to zero thermal
    noise photons at their frequencies at room temperature. We cannot simply interface
    superconducting devices with optical photons due their frequency mismatch and
    the destructive effect of optical photons on superconductors. Therefore, we use
    microwave-to-optics transducers that allow to convert microwave photons into optical
    ones and vice-versa. The transducers that we use are macroscopic electro-optic
    transducers using the Pockels effect in a disk-shaped Lithium Niobate whispering
    gallery mode resonator. By using a strong optical pump, photons from the two frequency
    domains experience a beam-splitter interaction and get converted from one to the
    other.\r\n\r\nWe measure the generated optical photons using elaborate optical
    setups, optical heterodyning and single photon detectors to gain knowledge about
    the qubit state or the converted microwave photons. Bridging the microwave and
    the optical world allows us to take advantage of both of their strengths but it
    also requires deep knowledge about both of their working principles.\r\n\r\nIn
    this work, we describe two experiments that our group conducted to showcase the
    opportunities that arise from interfacing superconducting qubits with optical
    photons but also the pitfalls, one may encounter on the way.\r\n\r\nIn the first
    experiment, we managed to all-optically read out a superconducting qubit. We show
    that the assignment fidelity, the probability that a measurement of the qubit
    state matches the prepared state, is close to equal for all-optical, microwave-to-optics
    and conventional microwave readout. We show T1 and T2 measurements for all three
    readout types and give an analysis of the noise caused by the optics. Finally,
    we show that the infrared light does not affect the qubit performance in a negative
    way but that the heating it causes does. This is an important insight that we
    used in the next experiment.\r\n\r\nThe second experiment is the upconversion
    of itinerant single microwave photons to the optical domain. We show that we can
    generate single microwave photons from a qubit-cavity system. We upconvert these
    single photons, measure them with a single photon detector and reconstruct their
    shape. By conducting a single photon Rabi measurement, we show correlations between
    the microwave and the optical domain. And by thorough signal-to-noise measurements
    and noise analysis, we find that we can generate single infrared photons with
    high signal-to-noise ratio 5.1 and low transducer added noise (<0.012 quanta).
    We show that this measurement creates a path towards entanglement of a superconducting
    qubit and an optical photon and what parameters need to be improved to achieve
    it. Additionally, this experiment is a proof of principle for an on-demand infrared
    single photon source. More generally, it allows to link microwave quantum technology
    in general to the optical domain."
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
- _id: LifeSc
- _id: SSU
acknowledgement: "The author of this work was supported by the European Research Council
  under grant no.\r\n101089099 (ERC CoG cQEO) and the European Union’s Horizon 2020
  research and innovation\r\nprogram under grant no. 899354 (FETopen SuperQuLAN).\r\nThis
  work was also supported by the European Research Council under grant nos. 758053\r\n(ERC
  StG QUNNECT), 101248662 (ERC POC CoupledEOT), and the European Innovation\r\nCouncil
  no. 101187231 (PathfinderOpen CIELO). This research was funded in whole or in part\r\nby
  the Austrian Science Fund (FWF) [10.55776/F71]. For open access purposes, the author\r\nhas
  applied a CC BY public copyright license to any author accepted manuscript version
  arising\r\nfrom this submission.\r\niii\r\nMy co-authors in the works mentioned
  later acknowledge generous support from the ISTFELLOW program, the NOMIS-ISTA fellowship,
  the Horizon Europe Program HORIZONCL4-2022-QUANTUM-01-SGA via Project No. 101113946
  OpenSuperQPlus100 and a DOC fellowship of the Austrian Academy of Sciences at IST
  Austria.\r\n"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Thomas
  full_name: Werner, Thomas
  id: 1fcd8497-dba3-11ea-a45e-c6fbd715f7c7
  last_name: Werner
  orcid: 0009-0001-2346-5236
citation:
  ama: Werner T. Interfacing superconducting qubits with optical photons. 2026. doi:<a
    href="https://doi.org/10.15479/AT-ISTA-21863">10.15479/AT-ISTA-21863</a>
  apa: Werner, T. (2026). <i>Interfacing superconducting qubits with optical photons</i>.
    Institute of Science and Technology Austria. <a href="https://doi.org/10.15479/AT-ISTA-21863">https://doi.org/10.15479/AT-ISTA-21863</a>
  chicago: Werner, Thomas. “Interfacing Superconducting Qubits with Optical Photons.”
    Institute of Science and Technology Austria, 2026. <a href="https://doi.org/10.15479/AT-ISTA-21863">https://doi.org/10.15479/AT-ISTA-21863</a>.
  ieee: T. Werner, “Interfacing superconducting qubits with optical photons,” Institute
    of Science and Technology Austria, 2026.
  ista: Werner T. 2026. Interfacing superconducting qubits with optical photons. Institute
    of Science and Technology Austria.
  mla: Werner, Thomas. <i>Interfacing Superconducting Qubits with Optical Photons</i>.
    Institute of Science and Technology Austria, 2026, doi:<a href="https://doi.org/10.15479/AT-ISTA-21863">10.15479/AT-ISTA-21863</a>.
  short: T. Werner, Interfacing Superconducting Qubits with Optical Photons, Institute
    of Science and Technology Austria, 2026.
corr_author: '1'
date_created: 2026-05-12T09:04:02Z
date_published: 2026-05-12T00:00:00Z
date_updated: 2026-05-20T13:35:43Z
day: '12'
ddc:
- '530'
- '537'
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: JoFi
doi: 10.15479/AT-ISTA-21863
ec_funded: 1
file:
- access_level: open_access
  checksum: a5b4d8dba83f96e955a3625c0eebee98
  content_type: application/pdf
  creator: twerner
  date_created: 2026-05-15T15:53:57Z
  date_updated: 2026-05-15T15:53:57Z
  file_id: '21879'
  file_name: 2026_Werner_Thomas_Thesis.pdf
  file_size: 9330516
  relation: main_file
- access_level: closed
  checksum: b41282beaacfb32472769b9e3b1758d8
  content_type: application/x-zip-compressed
  creator: twerner
  date_created: 2026-05-15T15:54:06Z
  date_updated: 2026-05-15T15:54:06Z
  file_id: '21880'
  file_name: 2026_Werner_Thomas_Thesis.zip
  file_size: 9370704
  relation: source_file
file_date_updated: 2026-05-15T15:54:06Z
has_accepted_license: '1'
keyword:
- Superconducting qubits
- Quantum optics
- Single photons and quantum effects
- Nonlinear optics
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
page: '97'
project:
- _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a
  grant_number: '101089099'
  name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states'
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
  call_identifier: H2020
  grant_number: '899354'
  name: Quantum Local Area Networks with Superconducting Qubits
- _id: 26336814-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '758053'
  name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: 5b807754-ab3d-11f0-914f-ff8c34502cc9
  grant_number: '101248662'
  name: Integrated optical coupling for low loss electro-optic interconnects
- _id: 91aaf765-16d5-11f0-9cad-a8e7e44cccb7
  grant_number: '101187231'
  name: 'Cavity-Integrated Electro-Optics: Measuring, Converting and Manipulating
    Microwaves with Light'
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
  grant_number: F07105
  name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
    of Superconducting Quantum Circuits
- _id: bdb7cfc1-d553-11ed-ba76-d2eaab167738
  grant_number: '101080139'
  name: Open Superconducting Quantum Computers (OpenSuperQPlus)
- _id: 9B861AAC-BA93-11EA-9121-9846C619BF3A
  name: NOMIS Fellowship Program
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '19073'
    relation: part_of_dissertation
    status: public
  - id: '21870'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Johannes M
  full_name: Fink, Johannes M
  id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
  last_name: Fink
  orcid: 0000-0001-8112-028X
title: Interfacing superconducting qubits with optical photons
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2026'
...
---
OA_place: repository
OA_type: green
_id: '21870'
abstract:
- lang: eng
  text: Superconducting qubits are a leading candidate for utility-scale quantum computing
    due to their fast gate speeds and steadily decreasing error rates. The requirement
    for millikelvin operating temperatures, however, creates a significant scaling
    bottleneck. Modular architectures using optical fiber links could bridge separate
    cryogenic nodes, but superconducting circuits do not have coherent optical transitions
    and microwave-to-optical conversion has not been shown for any non-classical photon
    state. In this work, we demonstrate the on-demand generation and tomographic reconstruction
    of itinerant single microwave photons at 8.9 GHz from a superconducting qubit.
    We upconvert this non-Gaussian state with a transducer added noise below 0.012
    quanta and count the converted telecom photons at 193.4 THz with a signal-to-noise
    ratio of up to 5.1$\pm$1.1. We characterize the trade-offs between throughput
    and noise, and establish a viable path toward heralded entanglement distribution
    and gate teleportation. Looking ahead, these results empower existing superconducting
    devices to take a key role in distributed quantum technologies and heterogeneous
    quantum systems.
acknowledgement: "We thank Fritz Diorico and Onur Hosten who suggested the filter
  cavity design, and gave important insights about the assembly and the testing of
  the FabryPerot filter cavities. Ekatrina Fedotova and Diego A.\r\nLancheros Naranjo
  worked on the filter cavity setup in\r\nthe early stages of this work. Gustavo Wiederhecker
  and\r\nYiewen Chu provided insights as to the origins of the\r\nobserved optical
  noise and Nicola Carlon Zambon suggested using telecom filters to mitigate it further.
  This\r\nwork was supported by the European Research Council under grant agreement
  no. 101089099 (ERC CoG\r\ncQEO), and 101248662 (ERC POC CoupledEOT), the\r\nEuropean
  Unions Horizon 2020 research and innovation\r\nprogram under grant agreement no.
  899354 (FETopen\r\nSuperQuLAN), the European Innovation Council no.\r\n101187231
  (PathfinderOpen CIELO), and the Austrian\r\nScience Fund (FWF) no. F7105 (SFB BeyondC).
  J.F.\r\nand L.K. acknowledge support from the Horizon Europe\r\nProgram HORIZON-CL4-2022-QUANTUM-01-SGA
  via\r\nProject No. 101113946 OpenSuperQPlus100. A.M. acknowledges support from the
  NOMIS-ISTA fellowship."
article_processing_charge: No
arxiv: 1
author:
- first_name: Thomas
  full_name: Werner, Thomas
  id: 1fcd8497-dba3-11ea-a45e-c6fbd715f7c7
  last_name: Werner
  orcid: 0009-0001-2346-5236
- first_name: Erfan
  full_name: Riyazi, Erfan
  id: 53322f94-5355-11ee-ae5a-ff6f81c87d51
  last_name: Riyazi
- first_name: Samarth
  full_name: Hawaldar, Samarth
  id: 221708e1-1ff6-11ee-9fa6-85146607433e
  last_name: Hawaldar
  orcid: 0000-0002-1965-4309
- first_name: Rishabh
  full_name: Sahu, Rishabh
  id: 47D26E34-F248-11E8-B48F-1D18A9856A87
  last_name: Sahu
  orcid: 0000-0001-6264-2162
- first_name: Georg M
  full_name: Arnold, Georg M
  id: 3770C838-F248-11E8-B48F-1D18A9856A87
  last_name: Arnold
  orcid: 0000-0003-1397-7876
- first_name: Paul Falthansl-Scheinecker
  full_name: Paul Falthansl-Scheinecker, Paul Falthansl-Scheinecker
  last_name: Paul Falthansl-Scheinecker
- first_name: Jennifer A. Sánchez
  full_name: Naranjo, Jennifer A. Sánchez
  last_name: Naranjo
- first_name: Dante
  full_name: Loi, Dante
  last_name: Loi
- first_name: Lucky N.
  full_name: Kapoor, Lucky N.
  last_name: Kapoor
- first_name: Martin
  full_name: Zemlicka, Martin
  id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87
  last_name: Zemlicka
  orcid: 0009-0005-0878-3032
- first_name: Liu
  full_name: Qiu, Liu
  id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac
  last_name: Qiu
  orcid: 0000-0003-4345-4267
- first_name: Andrei
  full_name: Militaru, Andrei
  id: d67706f8-8eb1-11ee-ad1b-9c30dfa19e0b
  last_name: Militaru
- first_name: Johannes M
  full_name: Fink, Johannes M
  id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
  last_name: Fink
  orcid: 0000-0001-8112-028X
citation:
  ama: Werner T, Riyazi E, Hawaldar S, et al. Electro-optic conversion of itinerant
    Fock states. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/arXiv.2602.00928">10.48550/arXiv.2602.00928</a>
  apa: Werner, T., Riyazi, E., Hawaldar, S., Sahu, R., Arnold, G. M., Paul Falthansl-Scheinecker,
    P. F.-S., … Fink, J. M. (n.d.). Electro-optic conversion of itinerant Fock states.
    <i>arXiv</i>. <a href="https://doi.org/10.48550/arXiv.2602.00928">https://doi.org/10.48550/arXiv.2602.00928</a>
  chicago: Werner, Thomas, Erfan Riyazi, Samarth Hawaldar, Rishabh Sahu, Georg M Arnold,
    Paul Falthansl-Scheinecker Paul Falthansl-Scheinecker, Jennifer A. Sánchez Naranjo,
    et al. “Electro-Optic Conversion of Itinerant Fock States.” <i>ArXiv</i>, n.d.
    <a href="https://doi.org/10.48550/arXiv.2602.00928">https://doi.org/10.48550/arXiv.2602.00928</a>.
  ieee: T. Werner <i>et al.</i>, “Electro-optic conversion of itinerant Fock states,”
    <i>arXiv</i>. .
  ista: Werner T, Riyazi E, Hawaldar S, Sahu R, Arnold GM, Paul Falthansl-Scheinecker
    PF-S, Naranjo JAS, Loi D, Kapoor LN, Zemlicka M, Qiu L, Militaru A, Fink JM. Electro-optic
    conversion of itinerant Fock states. arXiv, <a href="https://doi.org/10.48550/arXiv.2602.00928">10.48550/arXiv.2602.00928</a>.
  mla: Werner, Thomas, et al. “Electro-Optic Conversion of Itinerant Fock States.”
    <i>ArXiv</i>, doi:<a href="https://doi.org/10.48550/arXiv.2602.00928">10.48550/arXiv.2602.00928</a>.
  short: T. Werner, E. Riyazi, S. Hawaldar, R. Sahu, G.M. Arnold, P.F.-S. Paul Falthansl-Scheinecker,
    J.A.S. Naranjo, D. Loi, L.N. Kapoor, M. Zemlicka, L. Qiu, A. Militaru, J.M. Fink,
    ArXiv (n.d.).
corr_author: '1'
date_created: 2026-05-12T13:58:18Z
date_published: 2026-01-31T00:00:00Z
date_updated: 2026-05-20T13:35:42Z
day: '31'
department:
- _id: JoFi
- _id: GradSch
doi: 10.48550/arXiv.2602.00928
ec_funded: 1
external_id:
  arxiv:
  - '2602.00928'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2602.00928
month: '01'
oa: 1
oa_version: Preprint
project:
- _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a
  grant_number: '101089099'
  name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states'
- _id: 5b807754-ab3d-11f0-914f-ff8c34502cc9
  grant_number: '101248662'
  name: Integrated optical coupling for low loss electro-optic interconnects
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
  call_identifier: H2020
  grant_number: '899354'
  name: Quantum Local Area Networks with Superconducting Qubits
- _id: 91aaf765-16d5-11f0-9cad-a8e7e44cccb7
  grant_number: '101187231'
  name: 'Cavity-Integrated Electro-Optics: Measuring, Converting and Manipulating
    Microwaves with Light'
- _id: 26927A52-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: F07105
  name: Integrating superconducting quantum circuits
- _id: 9B861AAC-BA93-11EA-9121-9846C619BF3A
  name: NOMIS Fellowship Program
publication: arXiv
publication_status: draft
related_material:
  record:
  - id: '21863'
    relation: dissertation_contains
    status: public
scopus_import: '1'
status: public
title: Electro-optic conversion of itinerant Fock states
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: preprint
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2026'
...
---
OA_place: publisher
OA_type: hybrid
_id: '19073'
abstract:
- lang: eng
  text: The rapid development of superconducting quantum hardware is expected to run
    into substantial restrictions on scalability because error correction in a cryogenic
    environment has stringent input–output requirements. Classical data centres rely
    on fibre-optic interconnects to remove similar networking bottlenecks. In the
    same spirit, ultracold electro-optic links have been proposed and used to generate
    qubit control signals, or to replace cryogenic readout electronics. So far, these
    approaches have suffered from either low efficiency, low bandwidth or additional
    noise. Here we realize radio-over-fibre qubit readout at millikelvin temperatures.
    We use one device to simultaneously perform upconversion and downconversion between
    microwave and optical frequencies and so do not require any active or passive
    cryogenic microwave equipment. We demonstrate all-optical single-shot readout
    in a circulator-free readout scheme. Importantly, we do not observe any direct
    radiation impact on the qubit state, despite the absence of shielding elements.
    This compatibility between superconducting circuits and telecom-wavelength light
    is not only a prerequisite to establish modular quantum networks, but it is also
    relevant for multiplexed readout of superconducting photon detectors and classical
    superconducting logic.
acknowledgement: We thank F. Hassani and M. Zemlicka for assistance with qubit design
  and high-power readout, respectively, and P. Winkel and I. Pop at Karlsruhe Institute
  of Technology for providing the JPA. This work was supported by the European Research
  Council under grant nos. 758053 (ERC StG QUNNECT) and 101089099 (ERC CoG cQEO),
  and the European Union’s Horizon 2020 research and innovation program under grant
  no. 899354 (FETopen SuperQuLAN). This research was funded in whole, or in part,
  by the Austrian Science Fund (FWF) DOI 10.55776/F71. L.Q. acknowledges generous
  support from the ISTFELLOW programme and G.A. is the recipient of a DOC fellowship
  of the Austrian Academy of Sciences at IST Austria. Open access funding provided
  by Institute of Science and Technology (IST Austria).
article_number: '9470'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Georg M
  full_name: Arnold, Georg M
  id: 3770C838-F248-11E8-B48F-1D18A9856A87
  last_name: Arnold
  orcid: 0000-0003-1397-7876
- first_name: Thomas
  full_name: Werner, Thomas
  id: 1fcd8497-dba3-11ea-a45e-c6fbd715f7c7
  last_name: Werner
  orcid: 0009-0001-2346-5236
- first_name: Rishabh
  full_name: Sahu, Rishabh
  id: 47D26E34-F248-11E8-B48F-1D18A9856A87
  last_name: Sahu
  orcid: 0000-0001-6264-2162
- first_name: Lucky
  full_name: Kapoor, Lucky
  id: 84b9700b-15b2-11ec-abd3-831089e67615
  last_name: Kapoor
  orcid: 0000-0001-8319-2148
- first_name: Liu
  full_name: Qiu, Liu
  id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac
  last_name: Qiu
  orcid: 0000-0003-4345-4267
- first_name: Johannes M
  full_name: Fink, Johannes M
  id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
  last_name: Fink
  orcid: 0000-0001-8112-028X
citation:
  ama: Arnold GM, Werner T, Sahu R, Kapoor L, Qiu L, Fink JM. All-optical superconducting
    qubit readout. <i>Nature Physics</i>. 2025;21. doi:<a href="https://doi.org/10.1038/s41567-024-02741-4">10.1038/s41567-024-02741-4</a>
  apa: Arnold, G. M., Werner, T., Sahu, R., Kapoor, L., Qiu, L., &#38; Fink, J. M.
    (2025). All-optical superconducting qubit readout. <i>Nature Physics</i>. Springer
    Nature. <a href="https://doi.org/10.1038/s41567-024-02741-4">https://doi.org/10.1038/s41567-024-02741-4</a>
  chicago: Arnold, Georg M, Thomas Werner, Rishabh Sahu, Lucky Kapoor, Liu Qiu, and
    Johannes M Fink. “All-Optical Superconducting Qubit Readout.” <i>Nature Physics</i>.
    Springer Nature, 2025. <a href="https://doi.org/10.1038/s41567-024-02741-4">https://doi.org/10.1038/s41567-024-02741-4</a>.
  ieee: G. M. Arnold, T. Werner, R. Sahu, L. Kapoor, L. Qiu, and J. M. Fink, “All-optical
    superconducting qubit readout,” <i>Nature Physics</i>, vol. 21. Springer Nature,
    2025.
  ista: Arnold GM, Werner T, Sahu R, Kapoor L, Qiu L, Fink JM. 2025. All-optical superconducting
    qubit readout. Nature Physics. 21, 9470.
  mla: Arnold, Georg M., et al. “All-Optical Superconducting Qubit Readout.” <i>Nature
    Physics</i>, vol. 21, 9470, Springer Nature, 2025, doi:<a href="https://doi.org/10.1038/s41567-024-02741-4">10.1038/s41567-024-02741-4</a>.
  short: G.M. Arnold, T. Werner, R. Sahu, L. Kapoor, L. Qiu, J.M. Fink, Nature Physics
    21 (2025).
corr_author: '1'
date_created: 2025-02-23T23:01:57Z
date_published: 2025-03-01T00:00:00Z
date_updated: 2026-05-20T13:35:42Z
day: '01'
ddc:
- '530'
department:
- _id: JoFi
doi: 10.1038/s41567-024-02741-4
ec_funded: 1
external_id:
  isi:
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has_accepted_license: '1'
intvolume: '        21'
isi: 1
language:
- iso: eng
month: '03'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 26336814-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '758053'
  name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a
  grant_number: '101089099'
  name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states'
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
  call_identifier: H2020
  grant_number: '899354'
  name: Quantum Local Area Networks with Superconducting Qubits
- _id: 2671EB66-B435-11E9-9278-68D0E5697425
  name: Coherent on-chip conversion of superconducting qubit signals from microwaves
    to optical frequencies
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
  grant_number: F07105
  name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
    of Superconducting Quantum Circuits
publication: Nature Physics
publication_identifier:
  eissn:
  - 1745-2481
  issn:
  - 1745-2473
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
  link:
  - description: News on ISTA Website
    relation: press_release
    url: https://ista.ac.at/en/news/when-qubits-learn-the-language-of-fiberoptics/
  record:
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  - id: '21863'
    relation: dissertation_contains
    status: public
scopus_import: '1'
status: public
title: All-optical superconducting qubit readout
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: ba8df636-2132-11f1-aed0-ed93e2281fdd
volume: 21
year: '2025'
...
---
OA_place: repository
_id: '18953'
abstract:
- lang: eng
  text: The rapid development of superconducting quantum hardware is expected to run
    into significant I/O restrictions due to the need for large-scale error correction
    in a cryogenic environment. Classical data centers rely on fiber-optic interconnects
    to remove similar networking bottlenecks and to allow for reconfigurable, software-defined
    infrastructures. In the same spirit, ultra-cold electro-optic links have been
    proposed and used to generate qubit control signals, or to replace cryogenic readout
    electronics. So far, the latter suffered from either low efficiency, low bandwidth
    and the need for additional microwave drives, or breaking of Cooper pairs and
    qubit states. In this work we realize electro-optic microwave photonics at millikelvin
    temperatures to implement a radio-over-fiber qubit readout that does not require
    any active or passive cryogenic microwave equipment. We demonstrate all-optical
    single-shot-readout by means of the Jaynes-Cummings nonlinearity in a circulator-free
    readout scheme. Importantly, we do not observe any direct radiation impact on
    the qubit state as verified with high-fidelity quantum-non-demolition measurements
    despite the absence of shielding elements. This compatibility between superconducting
    circuits and telecom wavelength light is not only a prerequisite to establish
    modular quantum networks, it is also relevant for multiplexed readout of superconducting
    photon detectors and classical superconducting logic. Moreover, this experiment
    showcases the potential of electro-optic radiometry in harsh environments - an
    electronics-free sensing principle that extends into the THz regime with applications
    in radio astronomy, planetary missions and earth observation.
acknowledgement: "We thank F. Hassani and M. Zemlicka for assistance\r\nwith qubit
  design and high power readout respectively,\r\nand P. Winkel and I. Pop at KIT for
  providing the JPA.\r\nThis work was supported by the European Research\r\nCouncil
  under grant agreement no. 758053 (ERC StG\r\nQUNNECT) and no. 101089099 (ERC CoG
  cQEO), the\r\nEuropean Union’s Horizon 2020 research and innovation\r\nprogram under
  grant agreement no. 899354 (FETopen\r\nSuperQuLAN) and the Austrian Science Fund
  (FWF)\r\nthrough BeyondC (grant no. F7105). L.Q. acknowledges\r\ngenerous support
  from the ISTFELLOW programme\r\nand G.A. is the recipient of a DOC fellowship of
  the\r\nAustrian Academy of Sciences at IST Austria."
article_processing_charge: No
arxiv: 1
author:
- first_name: Georg M
  full_name: Arnold, Georg M
  id: 3770C838-F248-11E8-B48F-1D18A9856A87
  last_name: Arnold
  orcid: 0000-0003-1397-7876
- first_name: Thomas
  full_name: Werner, Thomas
  id: 1fcd8497-dba3-11ea-a45e-c6fbd715f7c7
  last_name: Werner
  orcid: 0009-0001-2346-5236
- first_name: Rishabh
  full_name: Sahu, Rishabh
  id: 47D26E34-F248-11E8-B48F-1D18A9856A87
  last_name: Sahu
  orcid: 0000-0001-6264-2162
- first_name: Lucky
  full_name: Kapoor, Lucky
  id: 84b9700b-15b2-11ec-abd3-831089e67615
  last_name: Kapoor
  orcid: 0000-0001-8319-2148
- first_name: Liu
  full_name: Qiu, Liu
  id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac
  last_name: Qiu
  orcid: 0000-0003-4345-4267
- first_name: Johannes M
  full_name: Fink, Johannes M
  id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
  last_name: Fink
  orcid: 0000-0001-8112-028X
citation:
  ama: Arnold GM, Werner T, Sahu R, Kapoor L, Qiu L, Fink JM. All-optical single-shot
    readout of a superconducting qubit. <i>arXiv</i>. doi:<a href="https://doi.org/10.48550/ARXIV.2310.16817">10.48550/ARXIV.2310.16817</a>
  apa: Arnold, G. M., Werner, T., Sahu, R., Kapoor, L., Qiu, L., &#38; Fink, J. M.
    (n.d.). All-optical single-shot readout of a superconducting qubit. <i>arXiv</i>.
    <a href="https://doi.org/10.48550/ARXIV.2310.16817">https://doi.org/10.48550/ARXIV.2310.16817</a>
  chicago: Arnold, Georg M, Thomas Werner, Rishabh Sahu, Lucky Kapoor, Liu Qiu, and
    Johannes M Fink. “All-Optical Single-Shot Readout of a Superconducting Qubit.”
    <i>ArXiv</i>, n.d. <a href="https://doi.org/10.48550/ARXIV.2310.16817">https://doi.org/10.48550/ARXIV.2310.16817</a>.
  ieee: G. M. Arnold, T. Werner, R. Sahu, L. Kapoor, L. Qiu, and J. M. Fink, “All-optical
    single-shot readout of a superconducting qubit,” <i>arXiv</i>. .
  ista: Arnold GM, Werner T, Sahu R, Kapoor L, Qiu L, Fink JM. All-optical single-shot
    readout of a superconducting qubit. arXiv, <a href="https://doi.org/10.48550/ARXIV.2310.16817">10.48550/ARXIV.2310.16817</a>.
  mla: Arnold, Georg M., et al. “All-Optical Single-Shot Readout of a Superconducting
    Qubit.” <i>ArXiv</i>, doi:<a href="https://doi.org/10.48550/ARXIV.2310.16817">10.48550/ARXIV.2310.16817</a>.
  short: G.M. Arnold, T. Werner, R. Sahu, L. Kapoor, L. Qiu, J.M. Fink, ArXiv (n.d.).
corr_author: '1'
date_created: 2025-01-29T11:11:34Z
date_published: 2023-10-25T00:00:00Z
date_updated: 2026-07-12T22:30:26Z
day: '25'
department:
- _id: JoFi
doi: 10.48550/ARXIV.2310.16817
ec_funded: 1
external_id:
  arxiv:
  - '2310.16817'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.48550/arXiv.2310.16817
month: '10'
oa: 1
oa_version: Preprint
project:
- _id: 26336814-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '758053'
  name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: bdadfa0d-d553-11ed-ba76-fb85edbd456a
  grant_number: '101089099'
  name: 'Cavity Quantum Electro Optics: Microwave photonics with nonclassical states'
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
  call_identifier: H2020
  grant_number: '899354'
  name: Quantum Local Area Networks with Superconducting Qubits
- _id: 2671EB66-B435-11E9-9278-68D0E5697425
  name: Coherent on-chip conversion of superconducting qubit signals from microwaves
    to optical frequencies
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
  grant_number: F07105
  name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
    of Superconducting Quantum Circuits
publication: arXiv
publication_status: draft
related_material:
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  - id: '19073'
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    status: public
  - id: '18871'
    relation: dissertation_contains
    status: public
status: public
title: All-optical single-shot readout of a superconducting qubit
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: preprint
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2023'
...
