Safi, Hossein; Babadi, Sina; Osahon, Isaac N. O.; Sparks, Adrian; Kostakis, Ioannis; Powell, Denise; Meredith, Wyn; Missous, Mohamed; Missous, Medi; Tavakkolnia, Iman; Haas, Harald
Chip-scale beam-shaped optical wireless system for high-speed and energy-efficient connectivity Journal Article
In: Advanced Photonics Nexus, vol. 5, no. 02, 2026, ISSN: 2791-1519.
Links | BibTeX | Tags: LRDC, optical wireless communication (OWC), orthogonal frequency-division multiplexing, Photonics, vertical-cavity surface-emitting lasers
@article{safi_chip-scale_2026,
title = {Chip-scale beam-shaped optical wireless system for high-speed and energy-efficient connectivity},
author = {Hossein Safi and Sina Babadi and Isaac N. O. Osahon and Adrian Sparks and Ioannis Kostakis and Denise Powell and Wyn Meredith and Mohamed Missous and Medi Missous and Iman Tavakkolnia and Harald Haas},
url = {https://www.spiedigitallibrary.org/journals/advanced-photonics-nexus/volume-5/issue-02/026018/Chip-scale-beam-shaped-optical-wireless-system-for-high-speed/10.1117/1.APN.5.2.026018.full},
doi = {10.1117/1.APN.5.2.026018},
issn = {2791-1519},
year = {2026},
date = {2026-03-01},
urldate = {2026-03-18},
journal = {Advanced Photonics Nexus},
volume = {5},
number = {02},
keywords = {LRDC, optical wireless communication (OWC), orthogonal frequency-division multiplexing, Photonics, vertical-cavity surface-emitting lasers},
pubstate = {published},
tppubtype = {article}
}
Ihsan, Asim; Asif, Muhammad; Safi, Hossein; Tavakkolnia, Iman; Haas, Harald
Efficient Service Differentiation and Energy Management in Hybrid WiFi/LiFi Networks Journal Article
In: IEEE Transactions on Green Communications and Networking, vol. 10, pp. 1335–1351, 2026, ISSN: 2473-2400.
Links | BibTeX | Tags: LiFi, LRDC, Network management and orchestration
@article{ihsan_efficient_2026,
title = {Efficient Service Differentiation and Energy Management in Hybrid WiFi/LiFi Networks},
author = {Asim Ihsan and Muhammad Asif and Hossein Safi and Iman Tavakkolnia and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11214543/},
doi = {10.1109/TGCN.2025.3624594},
issn = {2473-2400},
year = {2026},
date = {2026-01-01},
urldate = {2026-02-03},
journal = {IEEE Transactions on Green Communications and Networking},
volume = {10},
pages = {1335–1351},
keywords = {LiFi, LRDC, Network management and orchestration},
pubstate = {published},
tppubtype = {article}
}
Safi, Hossein; Dabiri, Mohammad Taghi; Cheng, Julian; Tavakkolnia, Iman; Haas, Harald
CubeSat-Enabled Free-Space Optics: Joint Data Communication and Fine Beam Tracking Journal Article
In: IEEE Transactions on Vehicular Technology, vol. 74, no. 12, pp. 19203–19216, 2025, ISSN: 0018-9545, 1939-9359.
Links | BibTeX | Tags: 6G, Free space optics, Low Earth Orbit (LEO) satellite communication, LRDC
@article{safi_cubesat-enabled_2025,
title = {CubeSat-Enabled Free-Space Optics: Joint Data Communication and Fine Beam Tracking},
author = {Hossein Safi and Mohammad Taghi Dabiri and Julian Cheng and Iman Tavakkolnia and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11071906/},
doi = {10.1109/TVT.2025.3586036},
issn = {0018-9545, 1939-9359},
year = {2025},
date = {2025-12-01},
urldate = {2026-02-05},
journal = {IEEE Transactions on Vehicular Technology},
volume = {74},
number = {12},
pages = {19203–19216},
keywords = {6G, Free space optics, Low Earth Orbit (LEO) satellite communication, LRDC},
pubstate = {published},
tppubtype = {article}
}
Kazemi, Hossein; Sarbazi, Elham; Crisp, Michael; El-Gorashi, Taisir E. H.; Elmirghani, Jaafar M. H.; Penty, Richard V.; White, Ian H.; Safari, Majid; Haas, Harald
A Novel Terabit Grid-of-Beam Optical Wireless Multi-User Access Network With Beam Clustering Journal Article
In: IEEE Transactions on Communications, vol. 73, no. 10, pp. 9152–9167, 2025, ISSN: 0090-6778, 1558-0857.
Links | BibTeX | Tags: LRDC, Network management and orchestration, Optical wireless communication, Vertical cavity surface emitting lasers
@article{kazemi_novel_2025,
title = {A Novel Terabit Grid-of-Beam Optical Wireless Multi-User Access Network With Beam Clustering},
author = {Hossein Kazemi and Elham Sarbazi and Michael Crisp and Taisir E. H. El-Gorashi and Jaafar M. H. Elmirghani and Richard V. Penty and Ian H. White and Majid Safari and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10949139/},
doi = {10.1109/TCOMM.2025.3558045},
issn = {0090-6778, 1558-0857},
year = {2025},
date = {2025-10-01},
urldate = {2026-02-03},
journal = {IEEE Transactions on Communications},
volume = {73},
number = {10},
pages = {9152–9167},
keywords = {LRDC, Network management and orchestration, Optical wireless communication, Vertical cavity surface emitting lasers},
pubstate = {published},
tppubtype = {article}
}
Huang, Yifan; Liu, Yi; Liu, Wenjie; Papadimitratos, Panos; Haas, Harald; Tavakkolnia, Iman
Interference-Resilient Optical Wireless Positioning via Machine Learning-Enhanced Subset Filtering Proceedings Article
In: 2025.
BibTeX | Tags: LRDC, machine learning, Optical wireless communication
@inproceedings{huang_interference-resilient_2025,
title = {Interference-Resilient Optical Wireless Positioning via Machine Learning-Enhanced Subset Filtering},
author = {Yifan Huang and Yi Liu and Wenjie Liu and Panos Papadimitratos and Harald Haas and Iman Tavakkolnia},
year = {2025},
date = {2025-09-01},
keywords = {LRDC, machine learning, Optical wireless communication},
pubstate = {published},
tppubtype = {inproceedings}
}
Ahmad, Rizwana; Nieminen, Arttu; Osahon, Isaac N. O.; Caglayan, Humeyra; Haas, Harald
Experimental Demonstration of 75 Gbps OAM Multiplexing System Using 1310 nm VCSEL Transmitter Proceedings Article
In: 2025 European Conference on Optical Communications (ECOC), pp. 1–4, IEEE, Copenhagen, Denmark, 2025, ISBN: 9798331595319.
Links | BibTeX | Tags: LRDC, Optical wireless communication, Vertical cavity surface emitting lasers
@inproceedings{ahmad_experimental_2025,
title = {Experimental Demonstration of 75 Gbps OAM Multiplexing System Using 1310 nm VCSEL Transmitter},
author = {Rizwana Ahmad and Arttu Nieminen and Isaac N. O. Osahon and Humeyra Caglayan and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11263377/},
doi = {10.1109/ECOC66593.2025.11263377},
isbn = {9798331595319},
year = {2025},
date = {2025-09-01},
urldate = {2026-02-03},
booktitle = {2025 European Conference on Optical Communications (ECOC)},
pages = {1–4},
publisher = {IEEE},
address = {Copenhagen, Denmark},
keywords = {LRDC, Optical wireless communication, Vertical cavity surface emitting lasers},
pubstate = {published},
tppubtype = {inproceedings}
}
Nieminen, Arttu; Ahmad, Rizwana; Haas, Harald; Caglayan, Humeyra
Paraxial orbital angular momentum beam under misaligned detection Journal Article
In: Optics Express, vol. 33, no. 17, pp. 36736, 2025, ISSN: 1094-4087.
Abstract | Links | BibTeX | Tags: LRDC, orbital angular momentum (OAM)
@article{nieminen_paraxial_2025,
title = {Paraxial orbital angular momentum beam under misaligned detection},
author = {Arttu Nieminen and Rizwana Ahmad and Harald Haas and Humeyra Caglayan},
url = {https://opg.optica.org/abstract.cfm?URI=oe-33-17-36736},
doi = {10.1364/OE.567919},
issn = {1094-4087},
year = {2025},
date = {2025-08-01},
urldate = {2026-02-03},
journal = {Optics Express},
volume = {33},
number = {17},
pages = {36736},
abstract = {This work presents an analytical framework for modeling a detected orbital angular momentum (OAM) spectrum of a Laguerre-Gaussian (LG) beam subject to tilt and lateral displacement. Firstly, we demonstrate that both types of misalignment generate OAM sidebands governed by the same functional form, each characterized by a distinct dimensionless parameter that depends on the beam’s size and wavelength. Secondly, our analysis reveals that increasing the LG beams azimuthal index (its topological charge) broadens the detected OAM spectrum. Lastly, we show that when both tilt and lateral displacement are present, the contribution of the original OAM mode can be tuned: specifically, by orienting the tilt and displacement in perpendicular directions, the resulting misalignment effects interfere destructively, thereby reducing crosstalk.},
keywords = {LRDC, orbital angular momentum (OAM)},
pubstate = {published},
tppubtype = {article}
}
Eldeeb, Hossien B.; Qaraqe, Marwa; Muhaidat, Sami; Ghrayeb, Ali; Tavakkolnia, Iman; Haas, Harald
Shaping Connectivity: Channel Modeling and Performance Analysis of Reconfigurable Intelligent Surfaces for IoV Visible Light Communication Journal Article
In: IEEE Transactions on Vehicular Technology, vol. 74, no. 8, pp. 12529–12543, 2025, ISSN: 0018-9545, 1939-9359.
Links | BibTeX | Tags: LRDC, transport, vehicular communications
@article{eldeeb_shaping_2025,
title = {Shaping Connectivity: Channel Modeling and Performance Analysis of Reconfigurable Intelligent Surfaces for IoV Visible Light Communication},
author = {Hossien B. Eldeeb and Marwa Qaraqe and Sami Muhaidat and Ali Ghrayeb and Iman Tavakkolnia and Harald Haas},
url = {https://ieeexplore.ieee.org/document/10938375/},
doi = {10.1109/TVT.2025.3554581},
issn = {0018-9545, 1939-9359},
year = {2025},
date = {2025-08-01},
urldate = {2025-08-27},
journal = {IEEE Transactions on Vehicular Technology},
volume = {74},
number = {8},
pages = {12529–12543},
keywords = {LRDC, transport, vehicular communications},
pubstate = {published},
tppubtype = {article}
}
King, Liam G.; Majlesein, Behnaz; Osahon, Isaac N. O.; Yoshida, Kou; Haas, Harald; Samuel, Ifor D. W.
Visible light communication using thermally activated delayed fluorescent OLEDs Journal Article
In: Device, pp. 100835, 2025, ISSN: 26669986.
Links | BibTeX | Tags: LRDC, OLEDs, visible-light communication (VLO)
@article{king_visible_2025,
title = {Visible light communication using thermally activated delayed fluorescent OLEDs},
author = {Liam G. King and Behnaz Majlesein and Isaac N. O. Osahon and Kou Yoshida and Harald Haas and Ifor D. W. Samuel},
url = {https://linkinghub.elsevier.com/retrieve/pii/S2666998625001486},
doi = {10.1016/j.device.2025.100835},
issn = {26669986},
year = {2025},
date = {2025-06-01},
urldate = {2025-08-27},
journal = {Device},
pages = {100835},
keywords = {LRDC, OLEDs, visible-light communication (VLO)},
pubstate = {published},
tppubtype = {article}
}
Yoshida, Kou; Majlesein, Behnaz; Chen, Cheng; Haas, Harald; Turnbull, Graham A.; Samuel, Ifor D. W.
High-speed organic light-emitting diodes based on dinaphthylperylene achieving 4-Gbps communication Journal Article
In: Advanced Photonics, vol. 7, no. 03, 2025, ISSN: 2577-5421.
Links | BibTeX | Tags: LRDC, OLEDs, visible-light communication (VLO)
@article{yoshida_high-speed_2025,
title = {High-speed organic light-emitting diodes based on dinaphthylperylene achieving 4-Gbps communication},
author = {Kou Yoshida and Behnaz Majlesein and Cheng Chen and Harald Haas and Graham A. Turnbull and Ifor D. W. Samuel},
url = {https://www.spiedigitallibrary.org/journals/advanced-photonics/volume-7/issue-03/036005/High-speed-organic-light-emitting-diodes-based-on-dinaphthylperylene-achieving/10.1117/1.AP.7.3.036005.full},
doi = {10.1117/1.AP.7.3.036005},
issn = {2577-5421},
year = {2025},
date = {2025-06-01},
urldate = {2025-08-27},
journal = {Advanced Photonics},
volume = {7},
number = {03},
keywords = {LRDC, OLEDs, visible-light communication (VLO)},
pubstate = {published},
tppubtype = {article}
}
Safi, Hossein; Dabiri, Mohammad Taghi; Babadi, Sina; Tavakkolnia, Iman; Haas, Harald
3D Coverage Performance of VCSEL Arrays in Indoor OWC Systems for 6G Applications Proceedings Article
In: IEEE INFOCOM 2025 - IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS), pp. 1–6, IEEE, London, United Kingdom, 2025, ISBN: 9798331543709.
Links | BibTeX | Tags: 6G, LRDC, Network management and orchestration, Optical wireless communication, Vertical cavity surface emitting lasers
@inproceedings{safi_3d_2025,
title = {3D Coverage Performance of VCSEL Arrays in Indoor OWC Systems for 6G Applications},
author = {Hossein Safi and Mohammad Taghi Dabiri and Sina Babadi and Iman Tavakkolnia and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11152841/},
doi = {10.1109/INFOCOMWKSHPS65812.2025.11152841},
isbn = {9798331543709},
year = {2025},
date = {2025-05-01},
urldate = {2026-02-05},
booktitle = {IEEE INFOCOM 2025 - IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS)},
pages = {1–6},
publisher = {IEEE},
address = {London, United Kingdom},
keywords = {6G, LRDC, Network management and orchestration, Optical wireless communication, Vertical cavity surface emitting lasers},
pubstate = {published},
tppubtype = {inproceedings}
}
Nacke, Richard; Pellegrino, Carmine; Lackner, David; Siefer, Gerald; Majlesein, Behnaz; Younus, Othman; Osahon, Isaac; Tavakkolnia, Iman; Bett, Andreas W.; Haas, Harald; Helmers, Henning
Application scenarios for simultaneous optical power and data transfer Proceedings Article
In: Jalali, Bahram (Ed.): Optical Power Delivery, pp. 20, SPIE, San Francisco, United States, 2025, ISBN: 9781510684669 9781510684676.
Links | BibTeX | Tags: LRDC, Network management and orchestration
@inproceedings{nacke_application_2025,
title = {Application scenarios for simultaneous optical power and data transfer},
author = {Richard Nacke and Carmine Pellegrino and David Lackner and Gerald Siefer and Behnaz Majlesein and Othman Younus and Isaac Osahon and Iman Tavakkolnia and Andreas W. Bett and Harald Haas and Henning Helmers},
editor = {Bahram Jalali},
url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/13359/3042965/Application-scenarios-for-simultaneous-optical-power-and-data-transfer/10.1117/12.3042965.full},
doi = {10.1117/12.3042965},
isbn = {9781510684669 9781510684676},
year = {2025},
date = {2025-03-01},
urldate = {2025-08-27},
booktitle = {Optical Power Delivery},
pages = {20},
publisher = {SPIE},
address = {San Francisco, United States},
keywords = {LRDC, Network management and orchestration},
pubstate = {published},
tppubtype = {inproceedings}
}
Du, Jia; Chen, Chen; Zeng, Zhihong; Wang, Dengke; Ye, Jia; Song, Jian; Haas, Harald
Flexible Waveform Design for RO-ISAC Based on OFDM-Embedded Maximum Length Sequence Journal Article
In: IEEE Wireless Communications Letters, pp. 1–1, 2025, ISSN: 2162-2337, 2162-2345.
Links | BibTeX | Tags: LRDC, Optical integrated sensing and communication (O-ISAC), Orthogonal frequency division multiplexing (OFDM)
@article{du_flexible_2025,
title = {Flexible Waveform Design for RO-ISAC Based on OFDM-Embedded Maximum Length Sequence},
author = {Jia Du and Chen Chen and Zhihong Zeng and Dengke Wang and Jia Ye and Jian Song and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11098738/},
doi = {10.1109/LWC.2025.3593253},
issn = {2162-2337, 2162-2345},
year = {2025},
date = {2025-01-01},
urldate = {2025-08-27},
journal = {IEEE Wireless Communications Letters},
pages = {1–1},
keywords = {LRDC, Optical integrated sensing and communication (O-ISAC), Orthogonal frequency division multiplexing (OFDM)},
pubstate = {published},
tppubtype = {article}
}
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}
}
Qidan, Ahmad Adnan; Alazwary, Khulood; El-Gorashi, Taisir; Safari, Majid; Haas, Harald; Penty, Richard V.; White, Ian H.; Elmirghani, Jaafar M. H.
BIA Transmission in Rate Splitting-based Optical Wireless Networks Journal Article
In: IEEE Transactions on Communications, pp. 1–1, 2025, ISSN: 0090-6778, 1558-0857.
Links | BibTeX | Tags: LRDC, Optical wireless communication, Rate splitting, Vertical cavity surface emitting lasers
@article{qidan_bia_2025,
title = {BIA Transmission in Rate Splitting-based Optical Wireless Networks},
author = {Ahmad Adnan Qidan and Khulood Alazwary and Taisir El-Gorashi and Majid Safari and Harald Haas and Richard V. Penty and Ian H. White and Jaafar M. H. Elmirghani},
url = {https://ieeexplore.ieee.org/document/11164782/},
doi = {10.1109/TCOMM.2025.3610166},
issn = {0090-6778, 1558-0857},
year = {2025},
date = {2025-01-01},
urldate = {2025-10-17},
journal = {IEEE Transactions on Communications},
pages = {1–1},
keywords = {LRDC, Optical wireless communication, Rate splitting, Vertical cavity surface emitting lasers},
pubstate = {published},
tppubtype = {article}
}
Kazemi, Hossein; Osahon, Isaac N. O.; Jiao, Tiankuo; Butler, David; Ledentsov, Nikolay; Titkov, Ilya; Haas, Harald
Real-Time Transmission of Uncompressed High-Definition Video Via A VCSEL-Based Optical Wireless Link With Ultra-Low Latency Miscellaneous
2025.
Abstract | Links | BibTeX | Tags: electronic engineering, FOS: Electrical engineering, information engineering, LRDC, Signal Processing (eess.SP)
@misc{kazemi_real-time_2025,
title = {Real-Time Transmission of Uncompressed High-Definition Video Via A VCSEL-Based Optical Wireless Link With Ultra-Low Latency},
author = {Hossein Kazemi and Isaac N. O. Osahon and Tiankuo Jiao and David Butler and Nikolay Ledentsov and Ilya Titkov and Harald Haas},
url = {https://arxiv.org/abs/2507.23746},
doi = {10.48550/ARXIV.2507.23746},
year = {2025},
date = {2025-01-01},
urldate = {2026-02-03},
publisher = {arXiv},
abstract = {Real-time transmission of high-resolution video signals in an uncompressed and unencrypted format requires an ultra-reliable and low-latency communications (URLLC) medium with high bandwidth to maintain the quality of experience (QoE) for users. We put forward the design and experimental demonstration of a high-performance laser-based optical wireless communication (OWC) system that enables high-definition (HD) video transmission with submillisecond latencies. The serial digital interface (SDI) output of a camera is used to transmit the live video stream over an optical wireless link by directly modulating the SDI signal on the intensity of a 940 nm vertical cavity surface emitting laser (VCSEL). The proposed SDI over light fidelity (LiFi) system corroborates error-free transmission of full HD (FHD) and 4K ultra-high-definition (UHD) resolutions at data rates of 2.97 Gb/s and 5.94 Gb/s, respectively, with a measured end-to-end latency of under 35 ns. Since SDI standards support various video formats and VCSELs are high-bandwidth and low-power devices, this presents a scalable and inexpensive solution for wireless connectivity between professional broadcast equipment using off-the-shelf SDI components.},
keywords = {electronic engineering, FOS: Electrical engineering, information engineering, LRDC, Signal Processing (eess.SP)},
pubstate = {published},
tppubtype = {misc}
}
Safi, Hossein; Ihsan, Asim; Eldeeb, Hossien B.; Bechadergue, Bastien; Tavakkolnia, Iman; Haas, Harald
Energy-Efficient Precoding for Dense VCSEL-Based OWC Systems Under a Cooperative Broadcast Model Miscellaneous
2025.
Abstract | Links | BibTeX | Tags: FOS: Physical sciences, LRDC, Optics (physics.optics)
@misc{safi_energy-efficient_2025,
title = {Energy-Efficient Precoding for Dense VCSEL-Based OWC Systems Under a Cooperative Broadcast Model},
author = {Hossein Safi and Asim Ihsan and Hossien B. Eldeeb and Bastien Bechadergue and Iman Tavakkolnia and Harald Haas},
url = {https://arxiv.org/abs/2508.18871},
doi = {10.48550/ARXIV.2508.18871},
year = {2025},
date = {2025-01-01},
urldate = {2026-02-03},
publisher = {arXiv},
abstract = {As 6G and beyond aim for sustainable, high-capacity wireless connectivity, optical wireless communication (OWC) has emerged as a compelling solution.Recent advances in vertical-cavity surface-emitting laser (VCSEL) arrays have significantly enhanced OWC performance, enabling high-speed, low-power data transmission. However, dense VCSEL deployments introduce challenges related to interference and energy efficiency (EE). This paper proposes a scalable precoding framework for EE maximization in fully cooperative VCSEL-based OWC broadcast systems. We formulate a non-convex optimization problem to design the precoding matrix under practical optical constraints while guaranteeing minimum user rates. To solve this, we apply Dinkelbach's method to handle the fractional objective and the inner approximation technique to iteratively convexify and solve the problem. Simulation results show that our approach consistently outperforms regularized zero-forcing in terms of EE, particularly in large-scale deployments, demonstrating its potential for next-generation sustainable dense OWC networks.},
keywords = {FOS: Physical sciences, LRDC, Optics (physics.optics)},
pubstate = {published},
tppubtype = {misc}
}
Younus, Othman; Majlesein, Behnaz; Nacke, Richard; Osahon, Isaac N. O.; Pellegrino, Carmine; Babadi, Sina; Tavakkolnia, Iman; Helmers, Henning; Haas, Harald
Multi-Segment Photonic Power Converters for Energy Harvesting and High-Speed Optical Wireless Communication Miscellaneous
2025.
Abstract | Links | BibTeX | Tags: electronic engineering, FOS: Electrical engineering, information engineering, LRDC, Signal Processing (eess.SP), Systems and Control (eess.SY)
@misc{younus_multi-segment_2025,
title = {Multi-Segment Photonic Power Converters for Energy Harvesting and High-Speed Optical Wireless Communication},
author = {Othman Younus and Behnaz Majlesein and Richard Nacke and Isaac N. O. Osahon and Carmine Pellegrino and Sina Babadi and Iman Tavakkolnia and Henning Helmers and Harald Haas},
url = {https://arxiv.org/abs/2510.06205},
doi = {10.48550/ARXIV.2510.06205},
year = {2025},
date = {2025-01-01},
urldate = {2026-02-03},
publisher = {arXiv},
abstract = {The demand for energy-efficient high-speed wireless communication, coupled with the rapid rise of IoT devices, requires systems that integrate power harvesting with optical data reception to eliminate the need for charging or battery replacements. Recent advances have explored the use of solar cells as optical receivers for high-speed data detection alongside power harvesting. textbackslashacsGaAs-based textbackslashacpPPC provide six times greater electron mobility than silicon- or cadmium telluride-based cells, enabling faster data detection and improved power efficiency. However, their bandwidth is constrained by junction capacitance, which increases with active area, creating a trade-off between power output and data rate. To address this, we propose and test multi-segment textbackslashacsGaAs-based textbackslashAcpPPC that serve as both energy harvesters and data detectors. By segmenting the active area into 2, 4, or 6 subcells, forming circular areas with diameters of 1, 1.5, or 2.08textasciitildemm, we reduce capacitance and boost bandwidth while preserving light collection. Fabricated on a semi-insulating textbackslashacGaAs substrate with etched trenches for electrical isolation, the series-connected subcells optimize absorption and minimize parasitic effects. The textbackslashAcpPPC were used for an eye-safe 1.5textasciitildem optical wireless link, employing textbackslashacOFDM with adaptive bit and power loading. The system achieved a world record data rate of 3.8textasciitildeGbps, which is four times higher than prior works. The system converts 39.7textbackslash% of optical power from a beam of 2.3textasciitildemW, although the segmentation increases the sensitivity of the alignment. These findings provide new solutions for off-grid backhaul for future communication networks, such as 6th generation (6G) cellular.},
keywords = {electronic engineering, FOS: Electrical engineering, information engineering, LRDC, Signal Processing (eess.SP), Systems and Control (eess.SY)},
pubstate = {published},
tppubtype = {misc}
}
Zeng, Zhihong; Chen, Chen; Wu, Xiping; Savović, Svetislav; Soltani, Mohammad Dehghani; Safari, Majid; Haas, Harald
Interference mitigation using optimised angle diversity receiver in LiFi cellular network Journal Article
In: Optics Communications, vol. 574, pp. 131125, 2025, ISSN: 00304018.
Links | BibTeX | Tags: LiFi, LRDC
@article{zeng_interference_2025,
title = {Interference mitigation using optimised angle diversity receiver in LiFi cellular network},
author = {Zhihong Zeng and Chen Chen and Xiping Wu and Svetislav Savović and Mohammad Dehghani Soltani and Majid Safari and Harald Haas},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0030401824008629},
doi = {10.1016/j.optcom.2024.131125},
issn = {00304018},
year = {2025},
date = {2025-01-01},
urldate = {2024-10-30},
journal = {Optics Communications},
volume = {574},
pages = {131125},
keywords = {LiFi, LRDC},
pubstate = {published},
tppubtype = {article}
}
Liu, Mingqing; Kazemi, Hossein; Safari, Majid; Tavakkolnia, Iman; Haas, Harald
A Comprehensive Comparison between Terahertz and Optical Wireless Communications Miscellaneous
2025.
Abstract | Links | BibTeX | Tags: electronic engineering, FOS: Electrical engineering, information engineering, LRDC, Signal Processing (eess.SP)
@misc{liu_comprehensive_2025,
title = {A Comprehensive Comparison between Terahertz and Optical Wireless Communications},
author = {Mingqing Liu and Hossein Kazemi and Majid Safari and Iman Tavakkolnia and Harald Haas},
url = {https://arxiv.org/abs/2503.23010},
doi = {10.48550/ARXIV.2503.23010},
year = {2025},
date = {2025-01-01},
urldate = {2026-02-03},
publisher = {arXiv},
abstract = {This paper presents a comprehensive quantitative comparison between Terahertz (THz) communication (TeraCom) and optical wireless communication (OWC) technologies, focusing on both indoor and outdoor environments. We propose a comparison method for TeraCom and vertical-cavity surface-emitting laser (VCSEL)-based OWC in indoor scenarios, incorporating misalignment effects by modeling the THz antenna radiation pattern within a multi-ray THz channel model and using a Gaussian beam model for VCSEL-based OWC. Unified beamwidth parameters allow for a detailed analysis of misalignment impact on both systems. Furthermore, we develop power consumption models for each technology, integrating key parameters such as THz phase noise, VCSEL non-linearities, and photodetector bandwidth-area tradeoffs. These models enable an in-depth analysis of energy efficiency in indoor environments, including multi-transmitter coverage scenarios. For outdoor scenarios, we summarize existing stochastic channel models addressing path loss, pointing errors, and small-scale fading for free space optics (FSO) and THz links. We then apply these models to unmanned aerial vehicle (UAV) applications to assess performance in dynamic conditions. Our results provide critical insights into the suitability of each technology for various deployment scenarios.},
keywords = {electronic engineering, FOS: Electrical engineering, information engineering, LRDC, Signal Processing (eess.SP)},
pubstate = {published},
tppubtype = {misc}
}