Beaconless Auto-Alignment for Single-Wavelength 4.18 Tbit/s Mode-Division Multiplexing Free-Space Optical Communications

Yiming Li; Gil Fernandes; David Benton; Antonin Billaud; Marco Fernandes; Mohammed Patel; Fernando Guiomar; Andrew Ellis

doi:10.1109/JLT.2025.3558177

Beaconless Auto-Alignment for Single-Wavelength 4.18 Tbit/s Mode-Division Multiplexing Free-Space Optical Communications

Yiming Li, Gil Fernandes, David Benton, Antonin Billaud, Marco Fernandes, Mohammed Patel, Fernando Guiomar, Andrew Ellis

Research output: Contribution to journal › Article › peer-review

3 Citations (SciVal)

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Abstract

Mode-division multiplexing has shown its ability to significantly increase the capacity of free-space optical communications. Accurate alignment of transmitter and receiver is crucial in maintaining performance, because a sub-optimal beam alignment will induce modal crosstalk. Conventionally, a beacon beam is necessary for system alignment due to multiple local maximums in the mode-division multiplexed beam profile. However, the beacon beam introduces excess system complexity, power consumption, and alignment errors. Here we demonstrate a beaconless system with significantly higher alignment accuracy and faster acquisition. Besides improving energy efficiency, the beaconless method also simplifies the implementation and calibration of pointing, acquisition, and tracking systems, enabling a record-high achievable information rate of 4.187 Tbit/s in a single-wavelength free-space optical link.

Original language	English
Pages (from-to)	6029-6036
Number of pages	8
Journal	Journal of Lightwave Technology
Volume	43
Issue number	13
Early online date	4 Apr 2025
DOIs	https://doi.org/10.1109/JLT.2025.3558177
Publication status	Published - Jul 2025

Bibliographical note

This accepted manuscript version is licensed under the Creative Commons Attribution License CC BY [https://creativecommons.org/licenses/by/4.0/], which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Funding

Research supported by EPSRC under Grants EP/T009047/1, EP/S003436/1, and EP/S016171/1, by FEDER through the CENTRO 2020 programme OR- CIP (CENTRO-01-0145-FEDER-022141), by FCT/MCTES through project OptWire (PTDC/EEI-TEL/2697/2021), by MSCA RISE programme through project DIOR (grant agreement no. 10100828), by H2020-EU under the Marie S.-Curie Grant 713694, and by FCT through the individual scientific employment program (2022.07168.CEECIND).

Keywords

Laser beams
Linear programming
Accuracy
Free-space optical communication
Multiplexing
Detectors
Crosstalk
Adaptive optics
Calibration
Training

Access to Document

10.1109/JLT.2025.3558177

Y Li et al_AAM_Beaconless_Auto-Alignment_for_Single-Wavelength_4.18_Tbit_s_Mode-Division_Multiplexing_Free-Space_Optical_Communications
This accepted manuscript version is licensed under the Creative Commons Attribution License CC BY [https://creativecommons.org/licenses/by/4.0/], which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Accepted author manuscript, 10.3 MBLicence: CC BY 4.0

Cite this

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title = "Beaconless Auto-Alignment for Single-Wavelength 4.18 Tbit/s Mode-Division Multiplexing Free-Space Optical Communications",

abstract = "Mode-division multiplexing has shown its ability to significantly increase the capacity of free-space optical communications. Accurate alignment of transmitter and receiver is crucial in maintaining performance, because a sub-optimal beam alignment will induce modal crosstalk. Conventionally, a beacon beam is necessary for system alignment due to multiple local maximums in the mode-division multiplexed beam profile. However, the beacon beam introduces excess system complexity, power consumption, and alignment errors. Here we demonstrate a beaconless system with significantly higher alignment accuracy and faster acquisition. Besides improving energy efficiency, the beaconless method also simplifies the implementation and calibration of pointing, acquisition, and tracking systems, enabling a record-high achievable information rate of 4.187 Tbit/s in a single-wavelength free-space optical link.",

keywords = "Laser beams, Linear programming, Accuracy, Free-space optical communication, Multiplexing, Detectors, Crosstalk, Adaptive optics, Calibration, Training",

author = "Yiming Li and Gil Fernandes and David Benton and Antonin Billaud and Marco Fernandes and Mohammed Patel and Fernando Guiomar and Andrew Ellis",

note = "This accepted manuscript version is licensed under the Creative Commons Attribution License CC BY [https://creativecommons.org/licenses/by/4.0/], which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.",

year = "2025",

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doi = "10.1109/JLT.2025.3558177",

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T1 - Beaconless Auto-Alignment for Single-Wavelength 4.18 Tbit/s Mode-Division Multiplexing Free-Space Optical Communications

AU - Li, Yiming

AU - Fernandes, Gil

AU - Benton, David

AU - Billaud, Antonin

AU - Fernandes, Marco

AU - Patel, Mohammed

AU - Guiomar, Fernando

AU - Ellis, Andrew

N1 - This accepted manuscript version is licensed under the Creative Commons Attribution License CC BY [https://creativecommons.org/licenses/by/4.0/], which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

PY - 2025/7

Y1 - 2025/7

N2 - Mode-division multiplexing has shown its ability to significantly increase the capacity of free-space optical communications. Accurate alignment of transmitter and receiver is crucial in maintaining performance, because a sub-optimal beam alignment will induce modal crosstalk. Conventionally, a beacon beam is necessary for system alignment due to multiple local maximums in the mode-division multiplexed beam profile. However, the beacon beam introduces excess system complexity, power consumption, and alignment errors. Here we demonstrate a beaconless system with significantly higher alignment accuracy and faster acquisition. Besides improving energy efficiency, the beaconless method also simplifies the implementation and calibration of pointing, acquisition, and tracking systems, enabling a record-high achievable information rate of 4.187 Tbit/s in a single-wavelength free-space optical link.

AB - Mode-division multiplexing has shown its ability to significantly increase the capacity of free-space optical communications. Accurate alignment of transmitter and receiver is crucial in maintaining performance, because a sub-optimal beam alignment will induce modal crosstalk. Conventionally, a beacon beam is necessary for system alignment due to multiple local maximums in the mode-division multiplexed beam profile. However, the beacon beam introduces excess system complexity, power consumption, and alignment errors. Here we demonstrate a beaconless system with significantly higher alignment accuracy and faster acquisition. Besides improving energy efficiency, the beaconless method also simplifies the implementation and calibration of pointing, acquisition, and tracking systems, enabling a record-high achievable information rate of 4.187 Tbit/s in a single-wavelength free-space optical link.

KW - Laser beams

KW - Linear programming

KW - Accuracy

KW - Free-space optical communication

KW - Multiplexing

KW - Detectors

KW - Crosstalk

KW - Adaptive optics

KW - Calibration

KW - Training

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JO - Journal of Lightwave Technology

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ER -

Beaconless Auto-Alignment for Single-Wavelength 4.18 Tbit/s Mode-Division Multiplexing Free-Space Optical Communications

Abstract

Bibliographical note

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Keywords

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