Maria Vargemidou’s research while affiliated with Aristotle University of Thessaloniki and other places

We demonstrate a silicon photonic coherent MIMO processor using a photonic Crossbar (Xbar) layout. Successful experimental validation of its performance as a 4×4 MIMO processor and a 3×3 MIMO with on-chip phase retrieval is presented.

A fully-automated SDN-controlled real-time operation of a hybrid Fiber-Wireless 10Gb/s FSO and 5Gb/s mmWave link across 7km-fiber and 0.5m-radio distance resilient at all weather conditions is experimentally presented, supporting 25μs beam-switching and zero-touch hard handover via tunable SFP+ transceivers and simple all-passive 1x2 C-/O-band diplexers.

A flexibly reconfigurable optical circuit switched edge network architecture relying on wavelength-tunable SFP+ transceivers is presented for the first time for reconfigurable, low-latency 5G/6G networks. The proposed solution employs traditional cost-effective, fixed-wavelength 10G SFP+ transceivers as grey optics towards the access side of the network and programmable tunable 10G SFP+ transceivers at edge part of the network at the Central Office premises, while allowing for flexible reconfiguration of the edge network all-passively via an additional AWG wavelength demultiplexer. The proposed solution allows to reconfigurably interconnect different access network end points to different processing and storage services or the core/metro network, with remote management and monitoring capabilities. The main component of the proposed network solution exploits a two-port Smart Network Interface Card (Smart NIC) X6 BlueFiled protoype by NVIDIA and a set of commercial 10G SFP transceivers. The operation of the network bridge is experimentally demonstrated for the first time, being fully characterized in terms of broadband wavelength support across the whole C-band and fast packet-slot operation within slots of 817 ms duration, validating its suitable for .

The rise of the 6G era promotes massive broadband wireless connectivity in dense multi-user networks, equipped with flexible X-haul transport schemes. This work presents the first experimental demonstration of the end-to-end signal flow of a flexible THz Fiber Wireless (FiWi) X-haul that aggregates and simultaneously transports the multiple Intermediate Frequency over Fiber (IFoF) streams of a mmWave Multiple Input Multiple Output (MIMO) antenna on a single wavelength in the analog domain. Specifically, the FiWi X-haul transmission relies on a pair of 150 GHz antennas with 256 radiating elements placed after a 7km-long fiber spool, acting as a THz wireless bridge that provides flexible, seamless last mile connectivity. In turn, mmWave access in the Radio Access Network (RAN) segment is provided by means of a cascaded MIMO Phased Array Antenna (PAA) hosting three analog Intermediate Frequency (IF) input ports with microwave filtering and RF beamsteering. The proposed THz FiWi multi-IFoF X-haul link transports three different V-band user beams, each supporting a 250Mbd QPSK signal with individual analog RF beamsteering anywhere within a 90o sector, mapping each beam at a different transport IF. The proposed system distributes a 1.5 Gb/s data rate in three steerable beams anywhere in the 90° field of view of the MIMO antenna or to unleash a peak aggregate rate of >10 Gb/s at a single beam-direction, forming a flexible THz multi-IFoF X-haul of a multi-beam mmWave antenna on a single-wavelength and a promising roadmap for future multi-user 6G RANs.