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

High-fidelity spatial mode transmission through multimode fiber via vectorial time reversal

Yiyu Zhou, Boris Braverman, Alexander Fyffe, Runzhou Zhang, Jiapeng Zhao, Alan Eli Willner, Zhimin Shi, Robert W. Boyd

Published Mar 22, 2020• 3 citations
OpenAlex

Abstract

The large number of spatial modes supported by multimode fibers constitutes a promising platform for a multitude of quantum and classical applications. However, the practical use of multimode fibers is severely hampered by modal crosstalk and polarization mixing. Here we show that high mode fidelity can be achieved for a large number of spatial modes propagating through a 1-km-long, standard, graded-index, multimode fiber by using vectorial time reversal. Vectorial time reversal is accomplished digitally by means of a single-shot measurement for each mode of interest, without the need to probe the entire transfer matrix of the fiber. We characterize the crosstalk for 210 modes, in each of the Laguerre-Gauss and Hermite-Gauss basis sets. Through the use of vectorial time reversal, we show an average mode fidelity above 80% for fiber without thermal or mechanical stabilization. Our method presents a practical tool for enhancing fiber-based quantum and classical applications.

Related papers

High-fidelity spatial mode transmission through a 1-km-long multimode fiber via vectorial time reversal

Yiyu Zhou, Boris Braverman, Alexander Fyffe +5 more

The large number of spatial modes supported by standard multimode fibers is a promising platform for boosting the channel capacity of quantum and classical communications by orders of magnitude. However, the practical use of long multimode fibers is severely hampered by modal crosstalk and polarization mixing. To overcome these challenges, we develop and experimentally demonstrate a vectorial time reversal technique, which is accomplished by digitally pre-shaping the wavefront and polarization of the forward-propagating signal beam to be the phase conjugate of an auxiliary, backward-propagating probe beam. Here, we report an average modal fidelity above 80% for 210 Laguerre-Gauss and Hermite-Gauss modes by using vectorial time reversal over an unstabilized 1-km-long fiber. We also propose a practical and scalable spatial-mode-multiplexed quantum communication protocol over long multimode fibers to illustrate potential applications that can be enabled by our technique.

arXiv:2003.09883•Nature Communications•Mar 25, 2021•70 citations

Higher-Dimensional Communications Using Multimode Fibers and Compact Components to Enable a Dense Set of Communicating Channels

Daniel A. Nolan

Higher dimensional communications are of interest for multiple reasons including increasing classical transmission capacity and more recently the quantum state transfer through these fibers using the many modes within the fibers. For quantum communications, this enables an increase in the number of bits per photon, increasing quantum fidelity, increasing error threshold and enabling hyperentanglement transfer among other possibilities. High dimensional quantum state transfer can be transported through multimode fiber using the many modes available. However, this transfer medium is limited by mode coupling among the various spatial and polarization modes. Here we consider how this mode coupling impacts the transfer process. We consider the fiber's modal properties including orbital angular momentum, modal group numbers, and principal modes. We also investigate and propose input and output optical components as well as fiber properties that mitigate the deleterious effects of mode coupling. We propose methods to circumvent this mode coupling using optical fibers, optical components and devices that are commercially available today or those that are undergoing intense global research such as Flat Optics.

Optics•Aug 7, 2024•3 citations

Near-perfect measuring of full-field transverse-spatial modes of light

Markus Hiekkamäki, Shashi Prabhakar, Robert Fickler

Along with the growing interest in using the transverse-spatial modes of light in quantum and classical optics applications, developing an accurate and efficient measurement method has gained importance. Here, we present a technique relying on a unitary mode conversion for measuring any full-field transverse-spatial mode. Our method only requires three consecutive phase modulations followed by a single mode fiber and is, in principle, error-free and lossless. We experimentally test the technique using a single spatial light modulator and achieve an average error of 4.2 % for a set of 9 different full-field Laguerre-Gauss and Hermite-Gauss modes with an efficiency of up to 70%. Moreover, as the method can also be used to measure any complex superposition state, we demonstrate its potential for quantum cryptography applications and in high-dimensional quantum state tomography.

arXiv:1909.01685•Optics Express•Oct 15, 2019•37 citations

Arbitrary spatial mode sorting in a multimode fiber

Hugo Defienne, Daniele Faccio

Sorting spatial optical modes is a key challenge that underpins many applications from superresolved imaging to high-dimensional quantum key distribution. However, to date, implementations of optical mode sorters only operate on specific sets of modes, such as those carrying orbital angular momentum, and therefore lack versatility with respect to operation with an arbitrary spatial basis. Here we demonstrate an arbitrary spatial mode sorter by harnessing the random mode mixing process occurring during light propagation in a multimode fiber by wave-front shaping. By measuring the transmission matrix of the fiber, we show sorting of up to 25 transverse spatial modes of the Fourier, Laguerre-Gaussian, and random basis to an arbitrary set of positions at the output. Our approach provides a spatial mode sorter that is compact, easy to fabricate, programable, and usable with any spatial basis, which is promising for quantum and classical information science.

arXiv:2004.05585•Physical Review A•Jun 24, 2020•12 citations

Modal division multiplexing of quantum and classical signals in few-mode fibers

Danilo Zia, Mario Zitelli, Gonzalo Carvacho +3 more

Mode-division multiplexing using multimode optical fibers has been intensively studied in recent years, in order to alleviate the transmission capacity crunch. Moreover, the need for secure information transmission based on quantum encryption protocols leads to investigating the possibility of multiplexing both quantum and classical signals in the same fiber. In this work, we experimentally study the modal multiplexing of both quantum and classical signals at telecom wavelengths, by using a few-mode fiber of 8 km and modal multiplexers/demultiplexers. We observe the existence of random-mode coupling at the quantum level, leading to cross-talk among both degenerate and non-degenerate channels. Our results demonstrate the feasibility of using few-mode fibers for simultaneously transmitting classical and quantum information, leading to an efficient implementation of physical information encryption protocols in spatial-division multiplexed systems.

arXiv:2412.17578•Dec 23, 2024•0 citations

Shaping single photons through multimode optical fibers using mechanical perturbations

Ronen Shekel, Ohad Lib, Rodrigo Gutiérrez–Cuevas +3 more

Multimode optical fibers support low-loss transmission of multiple spatial modes, allowing for the transport of high-dimensional, spatially encoded information. In particular, encoding quantum information in the transverse shape of photons may boost the capacity of quantum channels while using existing infrastructure. However, when photons propagate through a multimode fiber, their transverse shape gets scrambled because of mode mixing and modal interference. This is usually corrected using free-space spatial light modulators, inhibiting a robust all-fiber operation. In this work, we demonstrate an all-fiber approach for controlling the shape of single photons and the spatial correlations between entangled photon pairs, using carefully controlled mechanical perturbations of the fiber. We optimize these perturbations to localize the spatial distribution of a single photon or the spatial correlations of photon pairs in a single spot, enhancing the signal in the optimized spot by over an order of magnitude. Using the same approach, we show a similar enhancement for coupling light from a multimode fiber into a single-mode fiber.

arXiv:2306.02288•APL Photonics•Sep 1, 2023•9 citations
The large number of spatial modes supported by multimode fibers constitutes a promising platform for a multitude of quantum and classical applications. However, the practical use of multimode fibers is severely hampered by modal crosstalk and polarization mixing. Here we show that high mode fidelity can be achieved for a large number of spatial modes propagating through a 1-km-long, standard, graded-index, multimode fiber by using vectorial time reversal. Vectorial time reversal is accomplished digitally by means of a single-shot measurement for each mode of interest, without the need to probe the entire transfer matrix of the fiber. We characterize the crosstalk for 210 modes, in each of the Laguerre-Gauss and Hermite-Gauss basis sets. Through the use of vectorial time reversal, we show an average mode fidelity above 80% for fiber without thermal or mechanical stabilization. Our method presents a practical tool for enhancing fiber-based quantum and classical applications.
The large number of spatial modes supported by standard multimode fibers is a promising platform for boosting the channel capacity of quantum and classical communications by orders of magnitude. However, the practical use of long multimode fibers is severely hampered by modal crosstalk and polarization mixing. To overcome these challenges, we develop and experimentally demonstrate a vectorial time reversal technique, which is accomplished by digitally pre-shaping the wavefront and polarization of the forward-propagating signal beam to be the phase conjugate of an auxiliary, backward-propagating probe beam. Here, we report an average modal fidelity above 80% for 210 Laguerre-Gauss and Hermite-Gauss modes by using vectorial time reversal over an unstabilized 1-km-long fiber. We also propose a practical and scalable spatial-mode-multiplexed quantum communication protocol over long multimode fibers to illustrate potential applications that can be enabled by our technique.
Higher dimensional communications are of interest for multiple reasons including increasing classical transmission capacity and more recently the quantum state transfer through these fibers using the many modes within the fibers. For quantum communications, this enables an increase in the number of bits per photon, increasing quantum fidelity, increasing error threshold and enabling hyperentanglement transfer among other possibilities. High dimensional quantum state transfer can be transported through multimode fiber using the many modes available. However, this transfer medium is limited by mode coupling among the various spatial and polarization modes. Here we consider how this mode coupling impacts the transfer process. We consider the fiber's modal properties including orbital angular momentum, modal group numbers, and principal modes. We also investigate and propose input and output optical components as well as fiber properties that mitigate the deleterious effects of mode coupling. We propose methods to circumvent this mode coupling using optical fibers, optical components and devices that are commercially available today or those that are undergoing intense global research such as Flat Optics.
Along with the growing interest in using the transverse-spatial modes of light in quantum and classical optics applications, developing an accurate and efficient measurement method has gained importance. Here, we present a technique relying on a unitary mode conversion for measuring any full-field transverse-spatial mode. Our method only requires three consecutive phase modulations followed by a single mode fiber and is, in principle, error-free and lossless. We experimentally test the technique using a single spatial light modulator and achieve an average error of 4.2 % for a set of 9 different full-field Laguerre-Gauss and Hermite-Gauss modes with an efficiency of up to 70%. Moreover, as the method can also be used to measure any complex superposition state, we demonstrate its potential for quantum cryptography applications and in high-dimensional quantum state tomography.
Sorting spatial optical modes is a key challenge that underpins many applications from superresolved imaging to high-dimensional quantum key distribution. However, to date, implementations of optical mode sorters only operate on specific sets of modes, such as those carrying orbital angular momentum, and therefore lack versatility with respect to operation with an arbitrary spatial basis. Here we demonstrate an arbitrary spatial mode sorter by harnessing the random mode mixing process occurring during light propagation in a multimode fiber by wave-front shaping. By measuring the transmission matrix of the fiber, we show sorting of up to 25 transverse spatial modes of the Fourier, Laguerre-Gaussian, and random basis to an arbitrary set of positions at the output. Our approach provides a spatial mode sorter that is compact, easy to fabricate, programable, and usable with any spatial basis, which is promising for quantum and classical information science.
Mode-division multiplexing using multimode optical fibers has been intensively studied in recent years, in order to alleviate the transmission capacity crunch. Moreover, the need for secure information transmission based on quantum encryption protocols leads to investigating the possibility of multiplexing both quantum and classical signals in the same fiber. In this work, we experimentally study the modal multiplexing of both quantum and classical signals at telecom wavelengths, by using a few-mode fiber of 8 km and modal multiplexers/demultiplexers. We observe the existence of random-mode coupling at the quantum level, leading to cross-talk among both degenerate and non-degenerate channels. Our results demonstrate the feasibility of using few-mode fibers for simultaneously transmitting classical and quantum information, leading to an efficient implementation of physical information encryption protocols in spatial-division multiplexed systems.
Multimode optical fibers support low-loss transmission of multiple spatial modes, allowing for the transport of high-dimensional, spatially encoded information. In particular, encoding quantum information in the transverse shape of photons may boost the capacity of quantum channels while using existing infrastructure. However, when photons propagate through a multimode fiber, their transverse shape gets scrambled because of mode mixing and modal interference. This is usually corrected using free-space spatial light modulators, inhibiting a robust all-fiber operation. In this work, we demonstrate an all-fiber approach for controlling the shape of single photons and the spatial correlations between entangled photon pairs, using carefully controlled mechanical perturbations of the fiber. We optimize these perturbations to localize the spatial distribution of a single photon or the spatial correlations of photon pairs in a single spot, enhancing the signal in the optimized spot by over an order of magnitude. Using the same approach, we show a similar enhancement for coupling light from a multimode fiber into a single-mode fiber.