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}
}
Safi, Hossein; Ahmad, Rizwana; Tavakkolnia, Iman; Haas, Harald
Q-Learning for 3D Coverage in VCSEL-based Optical Wireless Systems Miscellaneous
2026.
Abstract | Links | BibTeX | Tags: FOS: Mathematics, LRDC, optical wireless communication (OWC), Optimization and Control (math.OC), vertical-cavity surface-emitting lasers
@misc{safi_q-learning_2026,
title = {Q-Learning for 3D Coverage in VCSEL-based Optical Wireless Systems},
author = {Hossein Safi and Rizwana Ahmad and Iman Tavakkolnia and Harald Haas},
url = {https://arxiv.org/abs/2602.03526},
doi = {10.48550/ARXIV.2602.03526},
year = {2026},
date = {2026-01-01},
urldate = {2026-06-03},
publisher = {arXiv},
abstract = {Beam divergence control is a key factor in maintaining reliable coverage in indoor optical wireless communication (OWC) systems as receiver height varies.Conventional systems employ fixed divergence angles, which result in significant coverage degradation due to the non-convex tradeoff between optical power concentration and spatial spread. In this paper, we introduce a reinforcement learning (RL)-based framework for dynamic divergence adaptation in vertical-cavity surface-emitting laser (VCSEL)-based OWC networks. By continuously interacting with the environment, the RL agent autonomously learns a near-optimal mapping between receiver height and beam divergence, thereby eliminating the need for analytical modeling or computationally intensive exhaustive search. Simulation results demonstrate that the proposed approach achieves up to 92% coverage at low receiver heights and maintains robust performance under challenging conditions, enabling scalable, real-time, and energy-efficient beam control for dense VCSEL array deployments in next-generation OWC systems.},
keywords = {FOS: Mathematics, LRDC, optical wireless communication (OWC), Optimization and Control (math.OC), vertical-cavity surface-emitting lasers},
pubstate = {published},
tppubtype = {misc}
}
Osahon, Isaac N. O.; Eldeeb, Hossien B.; Babadi, Sina; Younus, Othman I.; Ghaddar, Mohamad; Tavakkolnia, Iman; Haas, Harald
Experimental Demonstration of Kilometer-Scale Low-Complexity Multi-Gigabit VLC Proceedings Article
In: Optical Fiber Communication Conference (OFC) 2026, pp. M3H.1, Optica Publishing Group, Los Angeles, California, 2026, ISBN: 9781957171548.
Abstract | Links | BibTeX | Tags: LRDC, optical wireless communication (OWC), visible light communication (VLC)
@inproceedings{osahon_experimental_2026,
title = {Experimental Demonstration of Kilometer-Scale Low-Complexity Multi-Gigabit VLC},
author = {Isaac N. O. Osahon and Hossien B. Eldeeb and Sina Babadi and Othman I. Younus and Mohamad Ghaddar and Iman Tavakkolnia and Harald Haas},
url = {https://opg.optica.org/abstract.cfm?URI=OFC-2026-M3H.1},
doi = {10.1364/OFC.2026.M3H.1},
isbn = {9781957171548},
year = {2026},
date = {2026-01-01},
urldate = {2026-06-03},
booktitle = {Optical Fiber Communication Conference (OFC) 2026},
pages = {M3H.1},
publisher = {Optica Publishing Group},
address = {Los Angeles, California},
abstract = {We demonstrate a 1.2-km visible light communication (VLC) link achieving 6 Gb/s using a 450-nm laser with 0.1-W optical power, representing the longest reported multi-gigabit IM/DD VLC transmission with simple optical hardware.},
keywords = {LRDC, optical wireless communication (OWC), visible light communication (VLC)},
pubstate = {published},
tppubtype = {inproceedings}
}
Kazemi, Hossein; Younus, Othman; Osahon, Isaac N. O.; Ledentsov, Nikolay; Titkov, Ilya; Ledentsov, Nikolay; Haas, Harald
Demonstrating 80 Gb/s Optical Wireless Communication Using A Multi-Aperture VCSEL and A Multi-Mode Fiber-Coupled Receiver for Next-Generation LiFi Connectivity Proceedings Article
In: Optical Fiber Communication Conference (OFC) 2026, pp. M3H.2, Optica Publishing Group, Los Angeles, California, 2026, ISBN: 9781957171548.
Abstract | Links | BibTeX | Tags: LiFi, LRDC, optical wireless communication (OWC), vertical-cavity surface-emitting lasers
@inproceedings{kazemi_demonstrating_2026,
title = {Demonstrating 80 Gb/s Optical Wireless Communication Using A Multi-Aperture VCSEL and A Multi-Mode Fiber-Coupled Receiver for Next-Generation LiFi Connectivity},
author = {Hossein Kazemi and Othman Younus and Isaac N. O. Osahon and Nikolay Ledentsov and Ilya Titkov and Nikolay Ledentsov and Harald Haas},
url = {https://opg.optica.org/abstract.cfm?URI=OFC-2026-M3H.2},
doi = {10.1364/OFC.2026.M3H.2},
isbn = {9781957171548},
year = {2026},
date = {2026-01-01},
urldate = {2026-06-03},
booktitle = {Optical Fiber Communication Conference (OFC) 2026},
pages = {M3H.2},
publisher = {Optica Publishing Group},
address = {Los Angeles, California},
abstract = {We demonstrate a 940 nm single-mode multi-aperture VCSEL-based optical wireless link achieving
>
80 Gb/s data rates at
<
5 mW optical power, enabling ultra-high-speed, energy-efficient LiFi for next-generation networks.},
keywords = {LiFi, LRDC, optical wireless communication (OWC), vertical-cavity surface-emitting lasers},
pubstate = {published},
tppubtype = {inproceedings}
}
>
80 Gb/s data rates at
<
5 mW optical power, enabling ultra-high-speed, energy-efficient LiFi for next-generation networks.
Safi, Hossein; Osahon, Isaac N. O.; Tavakkolnia, Iman; Haas, Harald
Ethernet-over-OWC Using VCSELs: Transparent Gigabit Links with Low Latency and Robust Alignment Tolerance Miscellaneous
2026.
Abstract | Links | BibTeX | Tags: FOS: Physical sciences, LRDC, optical wireless communication (OWC), Optics (physics.optics), vertical-cavity surface-emitting lasers
@misc{safi_ethernet-over-owc_2026,
title = {Ethernet-over-OWC Using VCSELs: Transparent Gigabit Links with Low Latency and Robust Alignment Tolerance},
author = {Hossein Safi and Isaac N. O. Osahon and Iman Tavakkolnia and Harald Haas},
url = {https://arxiv.org/abs/2601.13878},
doi = {10.48550/ARXIV.2601.13878},
year = {2026},
date = {2026-01-01},
urldate = {2026-06-03},
publisher = {arXiv},
abstract = {We demonstrate a fully bidirectional 1 Gbs Ethernet over OWC link over a 1m free space path using a VCSEL-PIN pair and only commercially available components. The unamplified, transparent system achieves error-free operation, with a latency of less than 25 ns, and a centimetre-scale alignment tolerance.},
keywords = {FOS: Physical sciences, LRDC, optical wireless communication (OWC), Optics (physics.optics), vertical-cavity surface-emitting lasers},
pubstate = {published},
tppubtype = {misc}
}
Eldeeb, Hossien B.; Younus, Othman I.; Babadi, Sina; Osahon, Isaac N. O.; Ahmad, Rizwana; Tavakkolnia, Iman; Haas, Harald
Sub-Centimeter Indoor Optical Wireless Positioning Using An Optimized Machine Learning Technique Proceedings Article
In: GLOBECOM 2025 - 2025 IEEE Global Communications Conference, pp. 3360–3365, IEEE, Taipei, Taiwan, 2025, ISBN: 9798331577810.
Abstract | Links | BibTeX | Tags: LRDC, machine learning, optical wireless communication (OWC)
@inproceedings{eldeeb_sub-centimeter_2025,
title = {Sub-Centimeter Indoor Optical Wireless Positioning Using An Optimized Machine Learning Technique},
author = {Hossien B. Eldeeb and Othman I. Younus and Sina Babadi and Isaac N. O. Osahon and Rizwana Ahmad and Iman Tavakkolnia and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11432512/},
doi = {10.1109/GLOBECOM59602.2025.11432512},
isbn = {9798331577810},
year = {2025},
date = {2025-12-01},
urldate = {2026-06-03},
booktitle = {GLOBECOM 2025 - 2025 IEEE Global Communications Conference},
pages = {3360–3365},
publisher = {IEEE},
address = {Taipei, Taiwan},
abstract = {This paper proposes a novel indoor optical wireless positioning (IOWP) framework that aims to enhance localization precision and robustness through an advanced machine learning (ML)-driven fusion technique. Unlike traditional single model approaches, the proposed framework uses received signal strength (RSS) data to intelligently combine multiple lightweight ML algorithms, including K-Nearest Neighbors (KNN), Random Forest (RF), and Gaussian Process Regression (GPR). In the training phase, our system utilizes a performance- optimized weight allocation strategy to identify the optimal weights, harnessing the complementary strengths of individual models while mitigating their limitations to achieve exceptional generalization in complex indoor environments. A comprehensive evaluation is conducted under a realistic ray-traced channel model that incorporates typical light distributions, high-order multipath reflections from walls and objects, and mixed diffuse-reflective surface interactions. Performance is assessed in terms of mean positioning error (MPE), 90th percentile (P90) error, and computational complexity. Results demonstrate that the proposed method achieves an MPE of 0.5 cm and a P90 error below 1 cm, offering a practical and scalable solution for next-generation IOWP applications in smart environments.},
keywords = {LRDC, machine learning, optical wireless communication (OWC)},
pubstate = {published},
tppubtype = {inproceedings}
}
Soltani, Mohammad Dehghani; Tavakkolnia, Iman; Haas, Harald
Interference Reduction in LiFi Using an Optical Receiver with Dynamic FoV Proceedings Article
In: 2025 IEEE 101st Vehicular Technology Conference (VTC2025-Spring), pp. 1–6, IEEE, Oslo, Norway, 2025, ISBN: 9798331531478.
Links | BibTeX | Tags: field of view, LiFi, LRDC, optical wireless communication (OWC)
@inproceedings{soltani_interference_2025,
title = {Interference Reduction in LiFi Using an Optical Receiver with Dynamic FoV},
author = {Mohammad Dehghani Soltani and Iman Tavakkolnia and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11174500/},
doi = {10.1109/VTC2025-Spring65109.2025.11174500},
isbn = {9798331531478},
year = {2025},
date = {2025-06-01},
urldate = {2026-06-03},
booktitle = {2025 IEEE 101st Vehicular Technology Conference (VTC2025-Spring)},
pages = {1–6},
publisher = {IEEE},
address = {Oslo, Norway},
keywords = {field of view, LiFi, LRDC, optical wireless communication (OWC)},
pubstate = {published},
tppubtype = {inproceedings}
}
Ahmad, Rizwana; Caglayan, Humeyra; Haas, Harald
Misalignments in Orbital Angular Momentum-based Optical Wireless Communication Systems Proceedings Article
In: 2024 IEEE Globecom Workshops (GC Wkshps), pp. 1–6, IEEE, Cape Town, South Africa, 2024, ISBN: 9798331505677.
Links | BibTeX | Tags: LRDC, optical wireless communication (OWC), orbital angular momentum (OAM)
@inproceedings{ahmad_misalignments_2024,
title = {Misalignments in Orbital Angular Momentum-based Optical Wireless Communication Systems},
author = {Rizwana Ahmad and Humeyra Caglayan and Harald Haas},
url = {https://ieeexplore.ieee.org/document/11100949/},
doi = {10.1109/GCWkshp64532.2024.11100949},
isbn = {9798331505677},
year = {2024},
date = {2024-12-01},
urldate = {2026-06-03},
booktitle = {2024 IEEE Globecom Workshops (GC Wkshps)},
pages = {1–6},
publisher = {IEEE},
address = {Cape Town, South Africa},
keywords = {LRDC, optical wireless communication (OWC), orbital angular momentum (OAM)},
pubstate = {published},
tppubtype = {inproceedings}
}
Li, Juncheng; Huang, Yifan; Huang, Shenjie; Tavakkolnia, Iman; Haas, Harald; Safari, Majid
Integrated Communication and Positioning for IRS-Assisted LiFi Networks Proceedings Article
In: 2024 IEEE Wireless Communications and Networking Conference (WCNC), pp. 01–06, IEEE, Dubai, United Arab Emirates, 2024, ISBN: 9798350303582, (Place: Piscataway, NJ).
Abstract | Links | BibTeX | Tags: LiFi, LRDC, machine learning, optical wireless communication (OWC)
@inproceedings{li_integrated_2024,
title = {Integrated Communication and Positioning for IRS-Assisted LiFi Networks},
author = {Juncheng Li and Yifan Huang and Shenjie Huang and Iman Tavakkolnia and Harald Haas and Majid Safari},
url = {https://ieeexplore.ieee.org/document/10570819/},
doi = {10.1109/WCNC57260.2024.10570819},
isbn = {9798350303582},
year = {2024},
date = {2024-04-01},
urldate = {2026-06-03},
booktitle = {2024 IEEE Wireless Communications and Networking Conference (WCNC)},
pages = {01–06},
publisher = {IEEE},
address = {Dubai, United Arab Emirates},
series = {IEEE Wireless Communications and Networking Conference, WCNC},
abstract = {Light-fidelity (LiFi) is a networked optical wireless communication (OWC) solution to achieve high-speed mobile communications. To address the misalignment challenges encountered in laser-based LiFi, this study introduces an innovative full-coverage indoor LiFi system with integrated communication and positioning capabilities, leveraging intelligent reflected surfaces (IRSs). By design, the proposed system ensures successful wireless downlink connectivity, irrespective of the user's random location and orientation status. An algorithm is developed to ascertain the optimal deployment of both access points (APs) and IRS layers. Moreover, this study introduces a machine learning (ML)-based OWC positioning approach designed to enhance the accuracy of the user positioning, thereby effectively boosting the performance of the IRS-assisted communication system. Numerical results demonstrate the superiority of the proposed positioning approach over traditional methods in terms of average data rate.},
note = {Place: Piscataway, NJ},
keywords = {LiFi, LRDC, machine learning, optical wireless communication (OWC)},
pubstate = {published},
tppubtype = {inproceedings}
}
Osahon, Isaac N. O.; Rajbhandari, Sujan; Kostakis, Ioannis; Ihsan, Asim; Powell, Denise; Meredith, Wyn; Missous, Mohamed; Haas, Harald; Tang, Jianming
Experimental demonstration of 38 Gbps over 2.5 m OWC systems with eye-safe 850 nm SM-VCSELs Journal Article
In: IEEE Photonics Technology Letters, vol. 36, no. 3, pp. 139–142, 2024, ISSN: 1041-1135.
Abstract | Links | BibTeX | Tags: discrete multi-tone (DMT), eye safety, optical wireless communication (OWC), singlemode vertical cavity surface emitting laser (SM-VCSEL)
@article{osahon_experimental_2024,
title = {Experimental demonstration of 38 Gbps over 2.5 m OWC systems with eye-safe 850 nm SM-VCSELs},
author = {Isaac N. O. Osahon and Sujan Rajbhandari and Ioannis Kostakis and Asim Ihsan and Denise Powell and Wyn Meredith and Mohamed Missous and Harald Haas and Jianming Tang},
doi = {10.1109/LPT.2023.3337943},
issn = {1041-1135},
year = {2024},
date = {2024-02-01},
journal = {IEEE Photonics Technology Letters},
volume = {36},
number = {3},
pages = {139–142},
abstract = {With a directly modulated 850 nm single-mode vertical cavity surface emitting laser (SM-VCSEL), we experimentally achieve a gross data rate of ∼38 Gbps over a 2.5 m optical wireless communication (OWC) link at the 7% Reed-Solomon forward error correction (RS-FEC) limit. The OWC link is demonstrated using an eye-safe transmitted optical power of -1.47 dBm and discrete multi-tone (DMT) modulation with adaptive bit-and-power loading. The SM-VCSEL has a relative intensity noise (RIN) of ∼-137 dB/Hz, which is lower than that of a typical commercial 850 nm multimode VCSEL (∼-129 dB/Hz). Therefore, under almost identical OWC link operating conditions, the SM-VCSEL provides a gross data-rate increase of ∼19 Gbps and an optical signal-to-noise-ratio (SNR) gain of ∼5 dB compared to its multimode counterpart having a similar modulation bandwidth. Furthermore, we demonstrate an error-free net data rate of ∼17 Gbps at a received optical power of -7 dBm, which suggests the feasibility of utilising the SM-VCSEL to realise indoor gigabit OWC applications.},
keywords = {discrete multi-tone (DMT), eye safety, optical wireless communication (OWC), singlemode vertical cavity surface emitting laser (SM-VCSEL)},
pubstate = {published},
tppubtype = {article}
}