The ePhos project addresses the need to inspire the next generation in photonics, a transformative field shaping various aspects of our lives. Comprising a community of practice and a mobile augmented reality (AR) application named ePhosAR. These tools provide free and accessible photonics educational material for diverse audiences. The community of practice fosters collaborative learning through educational material, while the ePhosAR app, leveraging AR technology, transforms theoretical concepts into engaging experiences. The app is also accompanied by a board game for interactive learning. The dissemination efforts conducted at schools and universities received quite positive feedback, affirming the project's potential. The objectives of ePhos tools are to make photonics education easy, enjoyable, and accessible. Future work involves enriching and researching the tools' effectiveness in photonics education.

In this paper, we jointly study the real-time user association, traffic routing and x-Network Function (xNF) placement problem in an integrated Terrestrial and Satellite 6G Network (TN-SN), with the aim of maximizing the network energy efficiency and user acceptance ratio. We formulate the aforementioned problem as a Mixed Integer Linear Program (MILP), considering various capacity, power and flow conservation constraints for the integrated network, while also meeting the specific service requirements of each user. To tackle the increased complexity of the optimal solution, we also develop an efficient heuristic (named as TERA). Through extensive simulations, TERA demonstrates a notable superiority in energy efficiency compared to the current State-of-the-Art (SoA), achieving up to 85 % of the optimal with up to 87 % lower execution time even under challenging traffic load conditions.

We present an optimized Medium-Transparent MAC (oMT-MAC) protocol for Analog-RoF Fiber-Wireless 5G and beyond X-haul networks, capable of generating an optimum transmission schedule, which boosts the protocol's efficiency by utilizing the full delay budget of higher priority flows. Results show that oMT-MAC's optimization model can reduce delays by up to 20% for low-priority flows while maintaining the 5G Fronthaul and URLLC KPIs.

We propose an enhanced Medium-Transparent MAC (eMT-MAC) protocol for Analog-RoF Fiber-Wireless 5G and beyond X-haul networks, capable of handling variable packet sizes and wavelength sharing among multiple Remote Antenna Units (RAUs), thus increasing the protocol's efficiency for low-payload-length services such as URLLC/mMTC, while adding support for Point-to-Point links. Results show that eMT-MAC achieves high protocol efficiency, while also supporting wavelength sharing, and meets Low-layer split fronthaul specifications even for wavelength switching delays up to$12\mu\mathrm{s}$.

Phased Array Antennas are among the most important 5G enabling technologies. Optimizing a Phased Array Antenna (PAA) is an elaborate task, especially for PAAs with increased number of elements. Traditional optimization methods that are either based on greedy, local optimization such as gradient methods or consist of random walk solution space searches, are far from ideal for solving the problem of arbitrary pattern synthesis in 1D and 2D antenna arrays, mainly due to the high dimensional, multimodal functional domains involved but also due to the inherent limitations of these approaches e.g., the majority of these methods assume the object function is continuous or even differentiable. On the other hand, natural optimization methods, e.g., genetic algorithms, simulated annealing and particle swarm optimization can be used to tackle this problem efficiently. In this study, a genetic algorithm was developed for optimizing a Planar (2D) Phased Array Antenna, using a custom objective function so that the Array Factor has specific characteristics, in terms of directivity, beamwidth and side-lobe level (SLL). The experimental results showed that the genetic algorithm can be used for optimizing a 2D PAA with very satisfactory results.

We demonstrate experimentally a bandwidth-reconfigurable mmWave Fiber Wireless (FiWi) fronthaul bus topology for spectrally efficient and flexibly reconfigurable 5G Centralized-Radio Access Networks (C-RAN). The proposed fronthaul architecture includes four 1 Gb/s Intermediate Frequency over Fiber (IFoF) channels that can be flexibly allocated among two in-series Reconfigurable Optical Add/Drop Multiplexer (ROADM) integrated nodes, supporting in total 8 V-band 32-element Phased Array Antenna (PAA) terminals. The ROADM was fabricated as an integrated photonic device exploiting the ultra-low loss Si3N4TriPleX waveguide integration platform and an architectural layout based on cascaded MZI interleavers. The device has flat top response of 32.5 GHz with a Free Spectral Range (FSR) of 100 GHz and fiber-to-fiber losses of 5 dB, while the V-band PAA supports analog RF beamsteering capabilities within a 90°-sector and 1m wireless distance. Each of the FiWi links carries a 250 MBd QAM16 waveform enabling a total of 1 Gb/s rate per end user beam, complying with the 5G Key Performance Indicator (KPI) user-rate requirement. Bandwidth-reconfigurability is experimentally demonstrated by selectively dropping channels either at the first or at the second ROADM node, allowing in this way the bandwidth allocation to be flexibly defined between two different network segments. Both uplink and downlink performance are experimentally validated for different ratios of bandwidth allocation among the two nodes, revealing Error Vector Magnitude (EVM) values that meet the respective 3GPP signal quality specifications. The two-stage FiWi IFoF/mmWave fronthaul bus topology, based on a miniaturized, integrated, low loss Si3N4ROADM and supporting high-capacity wireless beamsteering capability can form a promising roadmap towards flexible and reconfigurable 5G C-RAN architectures.

We report an innovative solely optical architecture to implement the centralized wavelength conversion module of the CWC (controlled wavelength conversion) protocol [Papadimitriou, G.I. et al., 1999]. The proposed module was designed to distribute the conversion wavelengths to the corresponding converters in an unbiased manner taking into consideration the information carried by the control wavelength. The design of the optically controlled module is based on the use of optical logic circuits. These optical circuits distribute the available wavelengths by eliminating the need of optical to electronic translation of the network's feedback information and thus reducing drastically processing time. Furthermore, due to the all-optical nature of the network hub the reliability of the system is improved.

The centralized filtering of the transmitted packets has been the base of a family of high-performance protocols for WDM star networks. Protocols of this family have been proved to achieve a significantly higher performance than the well-known contention-oriented or round-robin protocols. However, the need for electronic control of the filtering mechanism as well as the use of slowly tunable acoustooptic filters have been limiting factors in their performance. Furthermore, since the network hub of WDM star networks represents a single point of failure, the extensive use of electronic circuits at this point reduces the reliability of the system. In this paper, an all-optical centralized protocol is introduced. According to this protocol, the passing of the transmitted packets to the star coupler is controlled by means of optical logic circuits, without the need of optical to electronic translation or electronic processing of the network feedback information. In this way, the processing time is drastically reduced, while the need for acoustooptic filters is eliminated. Therefore, a significant performance improvement is achieved. Furthermore, due to the all-optical nature of the network hub, the reliability of the system is improved. The performance of the proposed protocol is studied via extensive analytical and simulation results which indicate that a WDM star network operating under this protocol achieves a high throughput-delay performance under any load conditions.