1.
Majumder, Debparna; Bottrill, Kyle R. H.; Petropoulos, Periklis
Fibre-Based Dynamic Speckle Generation for Emulation of Atmospheric Turbulence Proceedings Article
In: 2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), pp. 1–1, 2025, ISSN: 2833-1052, (ISSN: 2833-1052).
Abstract | Links | BibTeX | Tags: Emulation, Europe, Free-space optical communication, Generators, Low earth orbit satellites, Optical fibers, Phase modulation, Satellites, Speckle, System performance
@inproceedings{majumder_fibre-based_2025,
title = {Fibre-Based Dynamic Speckle Generation for Emulation of Atmospheric Turbulence},
author = {Debparna Majumder and Kyle R. H. Bottrill and Periklis Petropoulos},
url = {https://ieeexplore.ieee.org/abstract/document/11110258},
doi = {10.1109/CLEO/Europe-EQEC65582.2025.11110258},
issn = {2833-1052},
year = {2025},
date = {2025-06-01},
urldate = {2025-10-08},
booktitle = {2025 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)},
pages = {1–1},
abstract = {Mitigating the impact of atmospheric turbulence induced speckle is a major challenge for free-space optical communications (FSOC). Such turbulence results in a multimodal, speckled beam which can be challenging to couple into the small active-area photoreceivers needed for high-bandwidth detection. Naturally, lab-based turbulence emulators are needed to benchmark FSOC system performance and develop turbulence mitigating subsystems. Common approaches to turbulence emulation include: rotating phase plates (PPs) [1], spatial light modulators (SLMs) [2] and turbulent-air generators [3]. In this work, we present a fibre-based, dynamic speckle generator, notable for its simplicity, cost-effectiveness (especially compared to SLMs and PPs), and unobtrusive in-lab use (compared to turbulent-air approaches). Unlike today's SLMs, which currently struggle to replicate the fast-changing distortion caused by high slew-rate Low-Earth-Orbit (LEO) satellite tracking, our all-fibre speckle generator can be easily scaled to faster modulation speeds (demonstrated here with a modest 230RPM).},
note = {ISSN: 2833-1052},
keywords = {Emulation, Europe, Free-space optical communication, Generators, Low earth orbit satellites, Optical fibers, Phase modulation, Satellites, Speckle, System performance},
pubstate = {published},
tppubtype = {inproceedings}
}
Mitigating the impact of atmospheric turbulence induced speckle is a major challenge for free-space optical communications (FSOC). Such turbulence results in a multimodal, speckled beam which can be challenging to couple into the small active-area photoreceivers needed for high-bandwidth detection. Naturally, lab-based turbulence emulators are needed to benchmark FSOC system performance and develop turbulence mitigating subsystems. Common approaches to turbulence emulation include: rotating phase plates (PPs) [1], spatial light modulators (SLMs) [2] and turbulent-air generators [3]. In this work, we present a fibre-based, dynamic speckle generator, notable for its simplicity, cost-effectiveness (especially compared to SLMs and PPs), and unobtrusive in-lab use (compared to turbulent-air approaches). Unlike today's SLMs, which currently struggle to replicate the fast-changing distortion caused by high slew-rate Low-Earth-Orbit (LEO) satellite tracking, our all-fibre speckle generator can be easily scaled to faster modulation speeds (demonstrated here with a modest 230RPM).
2.
Liu, Yi; Ali, Wajahat; Chen, Rui; Bamiedakis, Nikolaos; White, Ian H.; Haas, Harald; Crisp, Michael; Penty, Richard V.
A Scalable VCSEL-Array Optical Wireless Transmitter With Experimental Multi-Beam Prototype Journal Article
In: Journal of Lightwave Technology, pp. 1–7, 2025, ISSN: 1558-2213.
Abstract | Links | BibTeX | Tags: Arrays, Free-space optical communication, Interference, Lenses, LRDC, Microoptics, Optical arrays, optical communication equipment, Optical fibers, Optical receivers, Optical transmitters, Vertical cavity surface emitting lasers, verticalcavity surface-emitting lasers, Wireless communication
@article{liu_scalable_2025,
title = {A Scalable VCSEL-Array Optical Wireless Transmitter With Experimental Multi-Beam Prototype},
author = {Yi Liu and Wajahat Ali and Rui Chen and Nikolaos Bamiedakis and Ian H. White and Harald Haas and Michael Crisp and Richard V. Penty},
url = {https://ieeexplore.ieee.org/document/11189981},
doi = {10.1109/JLT.2025.3617131},
issn = {1558-2213},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-17},
journal = {Journal of Lightwave Technology},
pages = {1–7},
abstract = {A 5×5 VCSEL array-based optical wireless communication multi-beam transmitter is designed and simulated. Each element of the array addresses a separate spatial attocell. A microlens-array based homogenizer achieves uniform coverage at the receiver plane from each multi-mode VCSEL output. 1 m2 total coverage is achieved with each attocell covering an area of 400 cm2 at a range of 3 m. For a proof-of-concept demonstration a 1×3 channel VCSEL array-based transmitter prototype is experimentally tested. The performance is verified by demonstrating three channels achieving ∼ 0.12 mW/m2 uniform power with negligible optical interference to adjacent attocells (<-14 dB). With a simple receiver design using low cost, off-the-shelf components, each channel of the transmitter achieves ∼10 Gb/s throughput using OFDM within 7 cm lateral range and > 4 Gb/s within 12 cm lateral range at 3 m. The transmitter meets eye-safety restrictions and could be scaled to 250 Gb/s aggregate data rate by employing all 25 VCSELs with independent OFDM modulation.},
keywords = {Arrays, Free-space optical communication, Interference, Lenses, LRDC, Microoptics, Optical arrays, optical communication equipment, Optical fibers, Optical receivers, Optical transmitters, Vertical cavity surface emitting lasers, verticalcavity surface-emitting lasers, Wireless communication},
pubstate = {published},
tppubtype = {article}
}
A 5×5 VCSEL array-based optical wireless communication multi-beam transmitter is designed and simulated. Each element of the array addresses a separate spatial attocell. A microlens-array based homogenizer achieves uniform coverage at the receiver plane from each multi-mode VCSEL output. 1 m2 total coverage is achieved with each attocell covering an area of 400 cm2 at a range of 3 m. For a proof-of-concept demonstration a 1×3 channel VCSEL array-based transmitter prototype is experimentally tested. The performance is verified by demonstrating three channels achieving ∼ 0.12 mW/m2 uniform power with negligible optical interference to adjacent attocells (<-14 dB). With a simple receiver design using low cost, off-the-shelf components, each channel of the transmitter achieves ∼10 Gb/s throughput using OFDM within 7 cm lateral range and > 4 Gb/s within 12 cm lateral range at 3 m. The transmitter meets eye-safety restrictions and could be scaled to 250 Gb/s aggregate data rate by employing all 25 VCSELs with independent OFDM modulation.