Light that communicates: towards a new generation of wireless optical networks
Two leading international scientific journals - Scientific Reports and Advanced Optical Materials - have highlighted recent studies conducted by Italian research teams that have demonstrated an innovative communication system based on visible light (VLC) LEDs and fluorescent optical antennas in realistic applications, showing its excellent potential.
The research is the result of collaboration between the Institute of Telecommunications, Informatics and Photonics (TeCIP of the Sant'Anna School of Advanced Studies), the National Institute of Optics of the National Research Council in Sesto Fiorentino (CNR-INO), the LENS Laboratory, the Institute of Organometallic Chemistry of the CNR (CNR-ICCOM), the “Ugo Schiff” Department of Chemistry at the University of Florence and the Department of Chemistry and Industrial Chemistry at the University of Pisa.
The system, tested at the laboratories of the Sant'Anna School of Advanced Studies, shows how it is possible to create stable, low-cost wireless data transmission systems using commercial white LEDs and fluorescent solar concentrators (LSCs). this technology, which exploits materials capable of absorbing and re-emitting visible light, overcomes the limitations of traditional receivers, offering a wide field of view, greater signal collection efficiency and adequate response speed for real-world applications, such as high-definition video transmission or indoor Internet access.
From theory to practice: HD video transmitted via light
One of the main innovations introduced in this research is the combined use of a Luminescent Concentrator and high-power LEDs for lighting, thus exploiting the synergy between lighting and communication. In the first study, the researchers developed and tested a VLC system integrated with existing wired networks, such as Ethernet, capable of transmitting an HD video stream at 10 Mbit/s over a distance of 2 metres. The system, which uses a white ceiling LED as a transmitter and a VLC receiver based on LSC, developed by CNR-INO in collaboration with CNR-ICCOM and UniPi, showed excellent performance in terms of sensitivity and field of view, even without precise alignment between the transmitter and receiver. In other configurations, using more advanced modulations, transmission speeds of over 70 Mbit/s have been demonstrated.
‘Visible light communication has the potential to revolutionise communication networks, offering a secure and pervasive alternative to traditional wireless technologies, as any LED light source can be transformed into a data source,’ says Giulio Cossu, researcher at the Sant'Anna School of Advanced Studies in Pisa. ‘We have demonstrated that it is possible to achieve a stable and fast wireless optical link using simple components that can be easily integrated into everyday environments and networks.’
The study and preparation of luminescent solar concentrators, originally used for solar energy conversion, were carried out by a group led by Andrea Pucci, full professor at the Department of Chemistry and Industrial Chemistry at the University of Pisa, in collaboration with Massimo Calamante, senior researcher at CNR-ICCOM in Sesto Fiorentino.
In the second study, the researchers developed and compared three different fluorescent materials to identify the most suitable solutions for different applications: from indoor communications (Li-Fi) to laser-based communications. ‘These results demonstrate that it is possible to design innovative optical antennas, calibrating them for specific applications and choosing the most suitable material based on speed, efficiency and stability requirements,’ adds Jacopo Catani, research manager at CNR-INO, who coordinated the development and characterisation of the new receivers and their use in this type of application. ‘In particular, the H2 fluorophore represents an extremely promising platform for future generations of communication systems, considering that in the new 6G standard, light-based wireless communications will be a central element, especially in combination with new LED and white light laser sources.’
This paves the way for a new generation of wireless optical networks, ideal for environments where radio communications are limited or undesirable, but also in shops, hospitals, museums, schools and offices.
