Techniques émergentes de codage espace-temps pour les systèmes de communications optiques

Research in the field of optical fiber communications is advancing at a rapid pace in order to meet the growing needs for higher data rates. The main driving forces behind these advancements are the availability of multiple degrees of freedom in the optical fiber allowing for multiplexing more data: amplitude, phase and polarization state of the optical field, along with time and wavelength are already used in the deployed optical transmission systems. Yet, these systems are approaching their theoretical capacity limits and an extra dimension "space" is investigated to achieve the next capacity leap. However, packing several data channels in the same medium brings with it differential impairments and crosstalk that can seriously deteriorate the performance of the system. In this thesis, we focus on recent optical MIMO schemes based on polarization division multiplexing (PDM) and space division multiplexing (SDM). In both, we assess the performance penalties induced by non-unitary crosstalk and loss disparities among the channels arising from imperfections in the used optical components (fibers, amplifiers, multiplexers...), and suggest novel MIMO coding techniques known as Space-Time (ST) codes, initially designed for wireless multi-antenna channels, to mitigate them.La recherche dans le domaine des communications sur fibres optiques avance à un rythme rapide afin de satisfaire des demandes croissantes de communications à débits élevés. Les principaux moteurs de ces avancements sont la multitude de degrés de liberté offerts par la fibre permettant ainsi la transmission de plus de données: l'amplitude, la phase et l'état de polarisation du champ optique, ainsi que le temps et la longueur d'onde sont déjà utilisés dans les systèmes de transmission optique déployés. Pourtant, ces systèmes s'approchent de leur limite fondamentale de capacité et un degré supplémentaire: "la dimension spatiale" est étudié pour réaliser un saut qualitatif majeur en termes de capacité de transmission. Cependant, l'insertion de plusieurs flux de données dans le même canal de propagation induit également des pertes différentielles et de la diaphonie entre les flux, ce qui peut fortement réduire la qualité du système de transmission. Dans cette thèse, nous nous concentrons sur les systèmes de transmission optique de type MIMO basés sur un multiplexage en polarisation ou en modes de propagation. Dans les deux cas, nous évaluons la dégradation de la performance provoquée par une interférence inter-canaux non-unitaire et des disparités de gain entre les canaux engendrées par des imperfections dans les composants optiques utilisés (fibres, amplificateurs, multiplexeurs...), et proposons pour les combattre, de nouvelles techniques de codage pour les systèmes MIMO nommées "codes Spatio-Temporels" (ST), préalablement conçues pour les systèmes radios multi-antennaires

Flexural resistance of the polypropylene fibres reinforced cement mixes with waste material

The polypropylene (PP) fibers in shotcrete has been used for ground support and building strengthening, since several decades. However, the recent trend is to use the waste material in cementbased mixes to produce an eco-friendly material. Such waste material is the incineration fly ash (FA) that is classified as a hazardous product. This study is intended to establish the mechanical properties of fiber reinforced mortar in addition to cement or sand partial replacement by fly ash, in terms of flexural strength testing. The mechanical properties reflect the influence of the dosage of fiber content and the proportion of the fly ash on the flexural strength. The percentage of cement or sand was replaced by 0, 10, 20, and 30% fly ash. The dosage of fibers was 0, 0.6, 1.2, and 1.8 kg/m3. This green mix with fibers provides a partial substitute of cement as it is cheaper, by incorporating waste product, and saving energy consumption in the production. Due to growing interest in sustainable construction, engineers and architects are motivated to choose such materials which are more sustainable

Emerging space-time coding techniques for optical fiber transmission systems

La recherche dans le domaine des communications sur fibres optiques avance à un rythme rapide afin de satisfaire des demandes croissantes de communications à débits élevés. Les principaux moteurs de ces avancements sont la multitude de degrés de liberté offerts par la fibre permettant ainsi la transmission de plus de données: l'amplitude, la phase et l'état de polarisation du champ optique, ainsi que le temps et la longueur d'onde sont déjà utilisés dans les systèmes de transmission optique déployés. Pourtant, ces systèmes s'approchent de leur limite fondamentale de capacité et un degré supplémentaire: "la dimension spatiale" est étudié pour réaliser un saut qualitatif majeur en termes de capacité de transmission. Cependant, l'insertion de plusieurs flux de données dans le même canal de propagation induit également des pertes différentielles et de la diaphonie entre les flux, ce qui peut fortement réduire la qualité du système de transmission. Dans cette thèse, nous nous concentrons sur les systèmes de transmission optique de type MIMO basés sur un multiplexage en polarisation ou en modes de propagation. Dans les deux cas, nous évaluons la dégradation de la performance provoquée par une interférence inter-canaux non-unitaire et des disparités de gain entre les canaux engendrées par des imperfections dans les composants optiques utilisés (fibres, amplificateurs, multiplexeurs...), et proposons pour les combattre, de nouvelles techniques de codage pour les systèmes MIMO nommées "codes Spatio-Temporels" (ST), préalablement conçues pour les systèmes radios multi-antennaires.Research in the field of optical fiber communications is advancing at a rapid pace in order to meet the growing needs for higher data rates. The main driving forces behind these advancements are the availability of multiple degrees of freedom in the optical fiber allowing for multiplexing more data: amplitude, phase and polarization state of the optical field, along with time and wavelength are already used in the deployed optical transmission systems. Yet, these systems are approaching their theoretical capacity limits and an extra dimension "space" is investigated to achieve the next capacity leap. However, packing several data channels in the same medium brings with it differential impairments and crosstalk that can seriously deteriorate the performance of the system. In this thesis, we focus on recent optical MIMO schemes based on polarization division multiplexing (PDM) and space division multiplexing (SDM). In both, we assess the performance penalties induced by non-unitary crosstalk and loss disparities among the channels arising from imperfections in the used optical components (fibers, amplifiers, multiplexers...), and suggest novel MIMO coding techniques known as Space-Time (ST) codes, initially designed for wireless multi-antenna channels, to mitigate them

FilesForOFS2018.zip

Input and output audio for a distributed acoustic sensing solution suggested in a scientific paper submitted to the conference OFS (optical fiber sensors).<br

Flexural resistance of the polypropylene fibres reinforced cement mixes with waste material

The polypropylene (PP) fibers in shotcrete has been used for ground support and building strengthening, since several decades. However, the recent trend is to use the waste material in cementbased mixes to produce an eco-friendly material. Such waste material is the incineration fly ash (FA) that is classified as a hazardous product. This study is intended to establish the mechanical properties of fiber reinforced mortar in addition to cement or sand partial replacement by fly ash, in terms of flexural strength testing. The mechanical properties reflect the influence of the dosage of fiber content and the proportion of the fly ash on the flexural strength. The percentage of cement or sand was replaced by 0, 10, 20, and 30% fly ash. The dosage of fibers was 0, 0.6, 1.2, and 1.8 kg/m3. This green mix with fibers provides a partial substitute of cement as it is cheaper, by incorporating waste product, and saving energy consumption in the production. Due to growing interest in sustainable construction, engineers and architects are motivated to choose such materials which are more sustainable

Structural behavior of simply supported beams cast with hemp-reinforced concrete

© 2014, American Concrete Institute. The paper reports on an investigation of the structural behavior of a sustainable green concrete material developed in recent research works that were conducted at the American University of Beirut and were reported in the literature. The strength and thermal properties of the green hemp-reinforced concrete with coarse aggregate reduction were determined in previous studies. Eighteen structural beam specimens were prepared and tested to fail in flexure, shear, and bond splitting modes. A control mixture and two concrete mixtures reinforced with hemp fibers but lower coarse aggregate contents were adopted. The objective was to investigate the synergetic performance of hemp-concrete material when cast in reinforced concrete members. The results indicate that regardless of the mode of failure, hemp-concrete beams prepared with hemp fibers and less coarse aggregate had similar peak loads as the control beams. Also, hemp-concrete beams exhibited better load-deflection ductile behavior after the peak load