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

Programming 7-dimensional time-bin measurements inside a multi-mode fiber

Dylan Danese, Vatshal Srivastav, Saroch Leedumrongwatthanakun, Will McCutcheon, Mehul Malik

Published Jan 1, 2025• 0 citations
Publisher

Abstract

We program generalized projective measurements for high-dimensional pho-tonic time-bins by harnessing spatial-mode dispersion inside a commercial multi-mode fiber. We characterize the measurements in the time-domain via quantum process tomography, certifying an average fidelity of 93.22±0.32%.
DOI
10.1364/cleo_fs.2025.ff106_4

Related papers

Programmable Generalized Time-Bin Measurements using Complex Media

Vatshal Srivastav, Dylan Danese, Saroch Leedumrongwatthanakun +2 more

We harness the spatio-temporal coupling of light inside a commercial step-index multi-mode fibre to program generalized projective measurements for photonic time-bin in dimension up to 7 and use them to certify high-dimensional time-bin entanglement.

Frontiers in Optics•Jan 1, 2024•1 citation

Programming Quantum Measurements of Time inside a Complex Medium

Dylan Danese, Vatshal Srivastav, Will McCutcheon +2 more

The temporal degree-of-freedom of light is incredibly powerful for modern quantum technologies, enabling large-scale quantum computing architectures and record key-rates in quantum key distribution. However, the generalized measurement of large and complex quantum superpositions of the time-of-arrival of a photon remains a unique experimental challenge. Conventional methods based on unbalanced Franson-type interferometers scale poorly with dimension, requiring multiple cascaded devices and active phase stabilization. In addition, these are limited by construction to a restricted set of phase-only superposition measurements. Here we show how the coupling of spatial and temporal information inside a single multi-mode fiber can be harnessed to program completely generalized measurements for high-dimensional superpositions of photonic time-bin. Using the multi-spectral transmission matrix of the fiber, we find special sets of spatial modes that experience distinct dispersive delays through the fiber. By exciting coherent superpositions of these spatial modes, we engineer the equivalent of large, unbalanced multi-mode interferometers inside the fiber and use them to perform high-quality measurements of arbitrary time-bin superpositions in up to dimension 11. The single fiber functions as a scalable, common-path interferometer for time-bin qudits that significantly eases the experimental overheads of standard approaches based on unbalanced Franson-type interferometers, serving as an essential tool for quantum technologies that harness the temporal properties of light.

quant-pharXiv:2601.14565•Jan 22, 2026•0 citations

Programming quantum measurements of time inside a multimode fibre

Mehul Malik, Dylan Danese, Vatshal Srivastav +2 more

The temporal degree-of-freedom of light is incredibly exciting for many quantum technologies, ranging from photonic quantum computing to quantum key distribution. The generalized measurement of large and complex superpositions of the time-of-arrival of a photon presents a unique experimental challenge. Here we show how the coupling of spatial and temporal information inside a multi-mode fiber (MMF) can be harnessed to program generalized measurements for large photonic time-bin qudits. By exciting superpositions of special sets of spatial modes that are temporally unscattered through the fiber, we engineer arbitrary measurements of photon time-bins in dimensions up to 11. The single fiber serves as a scalable, common-path interferometer for time-bin qudits that significantly eases the experimental overheads of standard approaches based on unbalanced Franson-type interferometers.

Complex Light and Optical Forces•Mar 5, 2026•0 citations

Programmable High-Dimensional Quantum Circuits in Space and Time

Suraj Goel, Saroch Leedumrongwatthanakun, Natalia Herrera Valencia +7 more

We harness the complex mixing process inside a commercial multi-mode fibre to program high-dimensional linear optical circuits for photonic qudits encoded in transverse space and time-of-arrival, and demonstrate their use for high-dimensional entanglement certification.

Quantum 2.0 Conference and Exhibition•Jan 1, 2024•0 citations

Tomography of time-bin quantum states using time-resolved detection

Karolina Sedziak, Artur Czerwiński, Piotr Leszek Kolenderski

We present a method for measuring quantum states encoded in the temporal modes of photons. The basis for the multilevel quantum states is defined by the use of modes propagating in a dispersive medium, which is a fiber in this case. The propagation and time-resolved single-photon detection allow us to define a positive-operator valued measure (POVM). The POVM depends on the amount of dispersion and the characteristics of a detector. This framework is numerically tested by performing quantum state tomography on a large number of states for a set of realistic experimental settings. Finally, the average fidelity between the expected and reconstructed states is computed for qubits, qutrits, and entangled qubits.

arXiv:2003.11981•Physical Review A•Nov 24, 2020•24 citations

Tomographic reconstruction of time-bin-entangled qudits

Samantha J. Nowierski, Neal N. Oza, Prem Kumar +1 more

We describe an experimental implementation to generate and measure high-dimensional time-bin-entangled qudits. Two-photon time-bin entanglement is generated via spontaneous four-wave mixing in single-mode fiber. Unbalanced Mach-Zehnder interferometers transform selected time bins to polarization entanglement, allowing standard polarization-projective measurements to be used for complete quantum state tomographic reconstruction. Here we generate maximally entangled qubits $(d=2)$, qutrits $(d=3)$, and ququarts $(d=4)$, as well as other phase-modulated nonmaximally entangled qubits and qutrits. We reconstruct and verify all generated states using maximum-likelihood estimation tomography.

Physical Review A•Oct 19, 2016•18 citations
The temporal degree-of-freedom of light is incredibly powerful for modern quantum technologies, enabling large-scale quantum computing architectures and record key-rates in quantum key distribution. However, the generalized measurement of large and complex quantum superpositions of the time-of-arrival of a photon remains a unique experimental challenge. Conventional methods based on unbalanced Franson-type interferometers scale poorly with dimension, requiring multiple cascaded devices and active phase stabilization. In addition, these are limited by construction to a restricted set of phase-only superposition measurements. Here we show how the coupling of spatial and temporal information inside a single multi-mode fiber can be harnessed to program completely generalized measurements for high-dimensional superpositions of photonic time-bin. Using the multi-spectral transmission matrix of the fiber, we find special sets of spatial modes that experience distinct dispersive delays through the fiber. By exciting coherent superpositions of these spatial modes, we engineer the equivalent of large, unbalanced multi-mode interferometers inside the fiber and use them to perform high-quality measurements of arbitrary time-bin superpositions in up to dimension 11. The single fiber functions as a scalable, common-path interferometer for time-bin qudits that significantly eases the experimental overheads of standard approaches based on unbalanced Franson-type interferometers, serving as an essential tool for quantum technologies that harness the temporal properties of light.
The temporal degree-of-freedom of light is incredibly exciting for many quantum technologies, ranging from photonic quantum computing to quantum key distribution. The generalized measurement of large and complex superpositions of the time-of-arrival of a photon presents a unique experimental challenge. Here we show how the coupling of spatial and temporal information inside a multi-mode fiber (MMF) can be harnessed to program generalized measurements for large photonic time-bin qudits. By exciting superpositions of special sets of spatial modes that are temporally unscattered through the fiber, we engineer arbitrary measurements of photon time-bins in dimensions up to 11. The single fiber serves as a scalable, common-path interferometer for time-bin qudits that significantly eases the experimental overheads of standard approaches based on unbalanced Franson-type interferometers.
We present a method for measuring quantum states encoded in the temporal modes of photons. The basis for the multilevel quantum states is defined by the use of modes propagating in a dispersive medium, which is a fiber in this case. The propagation and time-resolved single-photon detection allow us to define a positive-operator valued measure (POVM). The POVM depends on the amount of dispersion and the characteristics of a detector. This framework is numerically tested by performing quantum state tomography on a large number of states for a set of realistic experimental settings. Finally, the average fidelity between the expected and reconstructed states is computed for qubits, qutrits, and entangled qubits.
We describe an experimental implementation to generate and measure high-dimensional time-bin-entangled qudits. Two-photon time-bin entanglement is generated via spontaneous four-wave mixing in single-mode fiber. Unbalanced Mach-Zehnder interferometers transform selected time bins to polarization entanglement, allowing standard polarization-projective measurements to be used for complete quantum state tomographic reconstruction. Here we generate maximally entangled qubits (d=2)(d=2)(d=2), qutrits (d=3)(d=3)(d=3), and ququarts (d=4)(d=4)(d=4), as well as other phase-modulated nonmaximally entangled qubits and qutrits. We reconstruct and verify all generated states using maximum-likelihood estimation tomography.