Savvas I. Raptis

High-Endurance, Low-loss Sb2Se3 Optical Switches on Silicon Nitride using Transparent Conductive Heaters

Xingshi Yu, Ipsita Chakraborty, Isaac E. Johnson, Savvas I. Raptis et autres

We report an electrically actuated, low-loss non-volatile optical switch based on the phase-change material (PCM) Sb2Se3 integrated on a silicon nitride (Si3N4) platform. The device is fabricated using an 8-inch wafer-scale process flow, demonstrating the feasibility of scalable manufacturing for photonic integrated …

Field Trial of a 50G HS-PON architecture supporting 1×16 All- Photonic Gateway and Time Sensitive Network Traffic

Maria Vargemidou, Chris Vagionas, Marios Gatzianas, Fabienne Saliou et autres

The first field trial of a Next Generation Central Office featuring a 1×16 all-photonic gateway comprising a C-/O-band glass diplexer-array and MEMS-based optical switch is reported, flexibly provisioning multiple traffic-classes of a 50G HS-PON and 10G C-band high-precision Time-Sensitive Network traffic at …

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Field Trial of a 50G HS-PON architecture supporting 1×16 All- Photonic Gateway and Time Sensitive Network Traffic

Maria Vargemidou, Chris Vagionas, Marios Gatzianas, Fabienne Saliou et autres

The first field trial of a Next Generation Central Office featuring a 1×16 all-photonic gateway comprising a C-/O-band glass diplexer-array and MEMS-based optical switch is reported, flexibly provisioning multiple traffic-classes of a 50G HS-PON and 10G C-band high-precision Time-Sensitive Network traffic at …

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Field Trial of SDN-controlled Point-to-MultiPoint Sensing of Weak Urban Events in 50G HS-PON

Margarita Fylaktaki, Maria Vargemidou, Fabienne Saliou, Erwan Deleurme et autres

The first field-trial of Point-to-MultiPoint sensing in field-deployed 50G HS-PONs is demon-strated exploiting real-time SDN-allocation of its wavelength-tunable sensing-channels and wavelet-transform-based DSP-techniques for detection of weak non-stationary urban events beyond the limits of conventional Fourier-transform spectrograms.

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Field Trial of SDN-controlled Point-to-MultiPoint Sensing of Weak Urban Events in 50G HS-PON

Margarita Fylaktaki, Maria Vargemidou, Fabienne Saliou, Erwan Deleurme et autres

The first field-trial of Point-to-MultiPoint sensing in field-deployed 50G HS-PONs is demon-strated exploiting real-time SDN-allocation of its wavelength-tunable sensing-channels and wavelet-transform-based DSP-techniques for detection of weak non-stationary urban events beyond the limits of conventional Fourier-transform spectrograms.

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On Jamming Detection: A Unified Method for Real-Time Detection Across Multiple Protocols & Attack Types

Alexandros I. Papadopoulos, Konstantinos Nikiforidis, Odysseas Grosomanidis, Eleni Chamou et autres

Jamming attacks continue to pose a significant threat to next-generation wireless networks, including Beyond 5G (B5G) and 6 G, by disrupting communication through intentional interference. In this paper, we introduce JAmming detection method baSed on Modulation scheme IdeNtification and Outlier Detector of …

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Jets Downstream of Collisionless Shocks: Recent Discoveries and Challenges

Eva Krämer, Florian Koller, Jonas Emil Suni, Adrian T. LaMoury et autres

Plasma flows with enhanced dynamic pressure, known as magnetosheath jets, are often found downstream of collisionless shocks. As they propagate through the magnetosheath, they interact with the surrounding plasma, shaping its properties, and potentially becoming geoeffective upon reaching the magnetopause. In recent …

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Ultra-thin and flexible microwave metasurface absorbers based on resistive patches

Savvas I. Raptis, Konstantinos Ntokos, Maria‐Thaleia Passia, Konstantina Tourlouki et autres

Abstract We introduce a systematic approach for designing ultrathin, flexible, and polarization-insensitive metasurface absorbers (MSAs), suitable for aviation applications, such as radar cross-section reduction of unmanned aerial vehicles. Metal-backed resistive patches are arranged on a flexible polyethylene terephthalate substrate of thickness about …

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Physics-Informed Metaheuristics for Fast RIS Codebook Compilation

Alexandros I. Papadopoulos, Savvas I. Raptis, Antonios X. Lalas, Konstantinos Votis et autres

Reconfigurable intelligent surfaces (RIS) can actively manipulate the wave propagation within a space, even in unconventional ways, enabling software-defined wireless propagation. Enabling real-time RIS operation requires a codebook, that is, a set of pre-calculated states of the RIS constituent elements that yield …

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Ultra-Thin and Flexible Metasurface Absorbers Mounted on a Highly Conductive CFRP Substrate

Konstantinos Ntokos, Maria‐Thaleia Passia, Savvas I. Raptis, Konstantina Tourlouki et autres

We propose two ultrathin, flexible and polarization-insensitive metasurface absorbers (MAs) for radar-cross section (RCS) reduction in UAV applications. Both absorbers are formed by resistive patches, which are arranged on a PET substrate of thickness 0.27 mm, classifying the MAs as ultrathin. A …

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An Accurate Semi-Analytical Model for Periodic Tunable Metasurfaces Electromagnetic Response

Savvas I. Raptis, Alexandros I. Papadopoulos, Loizos Symeonidis, Antonios X. Lalas et autres

Tunable metasurfaces, that is, 2D metamaterial structures with programmable functionalities have been a significant subject of research. The consideration of non-local effects in metasurfaces has been proven to be highly important in modeling the electromagnetic response of such structures. In this paper …

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Context Driven MEC Resource Allocation for Time-Critical AR Applications

Savvas I. Raptis, Iason Karakostas, Nikolaos Dimitriou, Dimitrios Tzovaras

Mobile Edge Computing (MEC) is a promising solution for delay-sensitive and computationally intensive applications mitigating the increased latency that cloud computing endures. This is achieved by delivering the computation resources in close proximity to the users' Mobile Devices (MDs) at the edge …

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