Dimitris UzunidisUniversity of West Attica | TEIATH · Department of Electrical & Electronics Engineering
Dimitris Uzunidis
Doctor of Philosophy
About
50
Publications
6,313
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205
Citations
Citations since 2017
Publications
Publications (50)
The paper describes the design and implementation of a virtual lab for on-line lab training on optical communications, part of the ‘Optical Communications’ course offered at the Dept. of Electrical & Electronic Engineering Educators, School of Pedagogical & Technological Education (ASPETE), Athens, Greece. The virtual lab is based on the OptiSystem...
As we enter the B5G/6G era, the converged Access and Metro segments are facing multi-faceted challenges including the heterogeneity of technologies, an unprecedented density and scale for the interconnection patterns, dynamic traffic profiles, and the inefficiency associated with the overprovisioning of dedicated connectivity resources. Here we pre...
Over the past fifty years, telecommunications has transformed, in an unprecedented manner , the way we live, work and communicate. For telecommunications, fixed networks are the one pillar and wireless networks the other. The wireless networks and their generations have been extensively investigated in the literature; however, the fixed networks la...
We introduce a closed-from expression which calculates the impact of SRS for channels spaced beyond 15 THz. This formalism is benchmarked against a numerical method in a four-band system with up to 300 channels, showing a maximum error of 0.18 dB in all examined cases.
Nowadays, service providers’ (SPs) need for efficient resource utilization solutions is more demanding than ever. The optimal use of the physical and virtual infrastructures guarantees that the waste of resources due to overdesign is minimized while the provided services enjoy the required quality of service levels. However, the prediction of the e...
The article describes a task on the feasibility and possible options regarding the implementation of actual optical communication links. The
task regards three (3) fiber-optic links with different transmission lengths and bit-rates and the students have to decide on the feasibility and
implementation options for those links. The task is formulate...
The paper proposes a teaching scenario for a 2-hour lesson regarding the association between circuit analysis and electromagnetic theory, conventional circuits and transmission lines as well as electromagnetic propagation and ray optics. The rationale behind that lesson was the observation that the majority of students could not identify the releva...
![Figure 1. Submarine network elements' evolution (1956-2022) [1-5].](profile/Charalampos-Papapavlou-2/publication/359892529/figure/fig1/AS:1145810624495616@1650193949014/Submarine-network-elements-evolution-1956-2022-1-5_Q320.jpg)
![Figure 4. Google cloud platform submarine network [3].](profile/Charalampos-Papapavlou-2/publication/359892529/figure/fig2/AS:1145810624491521@1650193949650/Google-cloud-platform-submarine-network-3_Q320.jpg)
Submarine networks have evolved alongside terrestrial ones over the past several decades. Although there are similarities between these two network categories (e.g., the need to cover ultra-long-haul distances and transport huge amounts of data), there are also important differences that have dictated their different evolutionary paths. Space divis...
Multi-Band systems are key enablers to simultaneously provide higher connectivity and higher capacity. In this work we propose a novel methodology which optimizes the physical layer performance of a multi-band system by selecting the appropriate launch power per channel. We apply this method to an S, C and L-band system and we demonstrate a balance...
We report the design of a TAPI SDN control plane for multi-band networks with externalized PLI-aware RMSA. We detail the architecture, data model extensions, algorithms and the implementation and validation in an emulated BT 22-ROADM network. © 2022 The Author(s) 1. Introduction Optical transmission exploiting multiple optical bands is the sole sol...
Search and Rescue (SaR) dogs are important assets in the hands of first responders, as they have the ability to locate the victim even in cases where the vision and or the sound is limited, due to their inherent talents in olfactory and auditory senses. In this work, we propose a deep-learning-assisted implementation incorporating a wearable device...
Optical multi-band (OMB) systems exploit the low-loss spectrum of the single mode fiber (SMF) and are key enablers to increase the transportation capacity and node connectivity of already deployed systems. The realization of OMB systems is mainly based on the technological advances on the component and system level, and for this purpose, a broad ga...
The optimum utilization of infrastructural resources is a highly desired yet cumbersome task for service providers to achieve. This is because the optimal amount of such resources is a function of various parameters, such as the desired/agreed quality of service (QoS), the service characteristics/profile, workload and service life-cycle. The advent...
We report a converged fixed wireless testbed spanning Metro-Access, built with no dedicated or mobile technology. An overarching intelligent orchestrator is implemented to tailor, in real-time, the fixed-line end-to-end QoS-aware bandwidth slices to the wireless system, taking into account the status of the entire network. Introduction The formatio...
We show that the combination of machine learning methods and analytical expressions can enhance the OSNIR estimation of an optical link of up to 2 dB compared with the use of an analytical expression alone. For this purpose, we exploit seven machine learning algorithms and we examine their OSNIR improvement for 3,000 different operational cases.
Connectivity in Multi-Band networks depends on the attainable optical performance for a number of system-level parameters like number of channels, modulation format and symbol rate. We present three connectivity schemes engaging E, S, C and L bands. Exploiting a rigorous OSNIR optimisation method we tabulate their optical reach and the correspondin...
Telecommunication networks are becoming the central linking institution of the Fourth Industrial Revolution. To cope with the associated capacity and connectivity challenges, transportation networks may explore the -neglected so far- remaining transmission bands in the second and third low attenuation windows of the optical fibre overcoming the C-b...
We propose a novel strategy which optimizes the power of all amplification bands in a Multi-Band system concurrently. The proposed method improves the OSNIR performance in S-band of more than 4 dB compared with optimization schemes in the literature.
To avoid the cost of overprovisioning in dedicated connectivity schemes, we developed a real-time reconfigurable connectivity platform spanning Metro and Access by utilising the dynamic data-plane of commercial PON technologies and a novel SDN control-plane. We demonstrated end-to-end orchestration of < 10 seconds in all cases. Introduction With th...
This paper proposes, designs, and validates a filterless metro network employing bidirectional transmission over a single fiber. Transmission impairments, dominated by cross talk, are specifically estimated leveraging on what we believe to be novel closed-form expressions to determine optical reach, launch power, and number of supported cascaded no...
Monitoring the behavior of animals (e.g., eating habits) can lead to conclusions regarding animal's welfare. To achieve this, remote monitoring of animal activity with the aid of inertial sensors and use of machine learning algorithms over the collected data can be used. However, these algorithms rely on handcrafted features extracted by statistica...
The migration of DataCenters into Metropolitan Area Networks creates new challenges which include the need for rapid service provisioning and recovery and new, cost-effective, connectivity schemes. Here we propose and demonstrate a truly dynamic transportation platform tailored for a metro network. The novelty of the proposed architecture is that t...
We propose a novel, cloud-integrated, Metro-Access node that is architected as a DataCentre, overcoming known Leaf-and-Spine limitations by exploiting PON systems and WDM for scalability. We demonstrate an SDN control-plane capable to rapidly instantiate connectivity resources within the node to interconnect intra-node servers with very low-latency...
Four Wave Mixing (FWM) is one of the main transmission impairments in coherent optical systems and a broad gamut of analytical expressions calculating its power already exists in the literature. Most of these expressions, such as the GN-model, assume that due to the large values of accumulated dispersion, each transmitted signal behaves as stationa...
![Fig. 2. Comparison of the matching of Eq. (9) and model of [13] with...](profile/Dimitris-Uzunidis-2/publication/313692031/figure/fig1/AS:668984831655940@1536509821386/Comparison-of-the-matching-of-Eq-9-and-model-of-13-with-model-of-4-see-text-for_Q320.jpg)
![Fig. 2 illustrates the matching with [4] where we subtracted](profile/Dimitris-Uzunidis-2/publication/313692031/figure/fig2/AS:668984831651843@1536509821422/llustrates-the-matching-with-4-where-we-subtracted_Q320.jpg)
Simplified, closed-form, mathematical expressions for Four Wave Mixing (FWM) in coherent optical systems are derived. FWM is an important limitation in both coherent OFDM (CO-OFDM) and Nyquist-WDM systems. The effect is also important in networks deploying Dispersion Shifted Fiber (DSF) and/or based on very narrow channel spacing. In this work, 1)...
Bandwidth requirements double up every three years. The main amount of this traffic is carried out by optical networks which form the backbone of communication systems. Accordingly, the optical fiber is the most efficient communication channel since it provides large bandwidth-5 THz for C-band and more than 20 THz if S and L-bands are loaded-and du...
![Table 1 . Maximum mismatch in [dB] between numerical and analytical...](profile/Dimitris-Uzunidis-2/publication/308915656/figure/tbl1/AS:614032918716416@1523408264013/Maximum-mismatch-in-dB-between-numerical-and-analytical-results-for-BER10-3_Q320.jpg)
Four Wave Mixing (FWM) is the dominant nonlinearity in coherent optical systems limiting transmission performance. Calculating the power of FWM along a fiber link enables us to estimate system performance and maximize fiber capacity. The latter is of great importance since capacity demands grow exponentially over time, namely 4 orders of magnitude...
Four Wave Mixing is the main source of nonlinearity in coherent optical OFDM systems that degrades the system performance. In this paper, based on a previously introduced model, we derive a closed form expression that calculates the FWM power. This model can be used for a fast estimation of system performance within a broad range of system paramete...
In this paper we discuss a simplified model which was derived for homogeneous optical links where all fiber spans are considered identical and its possible exploitation in heterogeneous optical links where the fiber spans can be different. This can be a practical scenario since combinations of different fiber types, i.e. single mode fiber (SMF) and...
We develop a closed-form expression in order to assess the nonlinear performance of flex-grid optical transmission systems. This simplified expression can estimate the performance of any super-channel of the spectrum allowing its introduction in Routing and Spectrum Assignment (RSA) algorithms which consider physical layer effects. The proposed met...
A simplified closed form expression for the noise power due to four-wave mixing in coherent OFDM systems is derived. The proposed model is in very good agreement with the exact model. The derived analytical expressions can be used in performance evaluation of systems employing CO-OFDM with any number of subcarriers and/or as an integral part of phy...
Improving the performance of electronic and optoelectronic components and systems has enabled the investigation of transmitting optical channels with data rates greater than 40 Gb/s. However, for transporting high capacity channels on demand over long distances, considerable signal processing is necessary, with current emphasis being on digital tec...
Projects
Project (1)
RESCUER aims to design and develop a First-Responder-centered technology toolkit that will empower the next-generation of First Responders (FR) by enhancing their operational capacity and safety, specifically in adverse conditions, both environmental and infrastructure-wise. Adopting the “HERO” (enHanced nEw eRa first respOnder) concept, RESCUER will deliver a toolkit offering (1) sense augmentation through enhanced sensorial input, (2) precise and infrastructure-less self-positioning, (3) cognitive support and multi-sense AR interfaces, improving their focus and capability to utilise information and (4) robust ad-hoc intra-team communications for both verbal and data exchanges, all delivered over enhanced power and communication autonomy features. Extending the above capabilities, through the concept of a building black box, RESCUER will also introduce the capability of extracting environment information “in situ and infrastructure-wise”, during a disaster. The project will achieve these goals using lightweight, non-obtrusive, and natural interaction with devices and sensors that offer additional information layers augmenting human sensing and operational capabilities, rendering FRs better aware of their surrounding conditions and able to make fast and efficient decisions to remain safe in the line of duty. RESCUER will employ a rigorous process for validating the tools developed, through field tests and three distinct pilots, supervising progression to new technologies and ensuring their adoption by FRs through iterative feedback acquisition and a dedicated provision for reducing cognitive overload. The ultimate goal of RESCUER is to introduce the next generation of FRs, who will be better protected, connected and situationally aware, with enhanced operational capacity and able to efficiently operate in infrastructure-less environments without power and communications network.
