Dissertations / Theses on the topic 'Modulation par décalage de phase'
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Al, Attar Houssein. "Bidirectional Electric Vehicle Charger Control." Thesis, Ecole centrale de Nantes, 2022. http://www.theses.fr/2022ECDN0043.
In this thesis, part of the chair Renault/Centrale Nantes, the aim is to design control strategies to improve the performance and efficiency of the bidirectional charger of the Electric Vehicle (EV). In the discharging mode, the new challenge is to design a Phase Shift Modulation (PSM) strategy to improve the operating zone and efficiency of the DC-DC converter. The control law is based on the DC-DC LLC gaininversion. In terms of cost, the contribution is mainly about the design of an optimization strategy, not only to reduce the sizing of the DC-DC LLC converter, but also to improve the performance of the Pulse Frequency Modulation (PFM) strategy. Then, a large signal model of the LLC converter based on the PSM strategy is developed. The main contribution consists of implementing robust control strategies, such as model-free control and adaptive super twisting control, combined with the PSM strategy. On the other hand, the key contribution leads to provide a hybrid control strategy of the charger in order to be able to regulate the DC bus voltage in the saturation zones of the DC-DCconverter. Finally, a new topology of an EV charger with the DAB structure is studied. A backstepping control strategy is proposed to regulate the DC bus voltage and the grid current. Different modulation strategies, such as single and dual phase shift modulation,are studied. Simulation results of real charger models are presented in order to highlight the effectiveness of the proposed control strategies
Abedrabou, Mohamed Cheiki. "Transmission par modulation à décalage d'une porteuse : conception et réalisation." Nancy 1, 1990. http://www.theses.fr/1990NAN10049.
Toulon, Bruno. "La mesure d'amplitudes complexes par interférométrie à décalage multi-latéral." Phd thesis, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00441279.
Aknoun, Sherazade. "Analyse quantitative d’images de phase obtenues par interféromètrie à décalage quadri-latéral. Applications en biologie." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4358/document.
The aim of this thesis, dedicated to the study and quantitative analysis of phase images obtained thanks to quadri-wave lateral shearing interferometry, is to caracterize a metrological tool and its three proposed different applications.This work has been done in collaboration between Institut Fresnel (Marseille, France) and Phasics company (Palaiseau, France) and continues that of Pierre Bon who has been in charge the application this technique to microscopy. This interferometric technique, developped by Phasics, for optical metrology and lasers characterization, allows to record complex eletromagnetic field maps thanks to a wave front measurement. By using it in the microscope image plane, one can obtain inetnsity and optical path difference images of a semi-transparent biological sample. this technique is now considered as a new quantitative phase contrast technique.The first part of this manuscript will be a state of the art of quantitative microscopy techniques. The issues of quantification and its meanings in the framework of different fluorescent and phase based techniques will be discussed.A description of the technique that is used and its comparison with similar phase techniques will be done.The measurement, under the projective approximation, is studied leading to different variables. We show different applications concerning isotropic elements in a first part and anisotropic elements in the second one.We show how this measurement is trnasposed to the third dimensions allowing three dimensional imaging and complete reconstruction of refractive index maps of biological samples
Bon, Pierre. "Imagerie microscopique de champs électromagnétiques par interférométrie à décalage quadri-latéral. Applications à la biologie." Thesis, Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30036.
The aim of this thesis is the use of a quadriwave lateral shearing interferometer for transmission microscopic imaging. First developped for optical metrology and laser beam caracterisation by the Phasics company (Palaiseau), this interferometric technique gives complexe electromagnetic field cartography by wavefront sensing. Using a microscope in imaging conditions, we obtained intensity and optical path difference images introduced by a semi-transparent sample. Thereby, we defined a new quantitative phase contrast technique.This work is co-directed by the Fresnel Institute and the Phasics company (CIFRE convention), in collaboration with the Centre Immunologique de Marseille Luminy. In this thesis, first we discuss the wavefront sensor use as a sensor plugged on the classical optical microscope image plane ; then we consider two models for optical path difference image formation. The first one, named object space projection, supposes a direct measurement of the optical path difference introduced by a sample. We show that this hypothesis is valid for two particular applications : dry matter determination within a biological sample, and temperature distribution induced by gold nano-particule heating. Thesecond model takes into account the simple sample diffraction and the optical device filtering depending on the illumination angle. This second approach allows us to build a model for intensity and optical path difference image formation for any planewave illumination. So we studied the image formation from a spatially partial incoherent illumination to a complete incoherent illumination. We made electromagnetic field measurements with the wavefront sensor in this last case. Then we discuss semi-transparent tomographic reconstruction by measurements in different imaging planes.One chapter is dedicated to quantitative phase imaging in biology, in particular with mitotic index determination within a cell population
Rizzi, Julien. "Imagerie de phase quantitative par interférométrie à décalage quadri-latéral. Application au domaine des rayons x durs." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00917590.
Rizzi, J. "Imagerie de phase quantitative par interféromètre à décalage quadri-latéral. Application au domaine des rayons X durs." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-01020084.
Hanna, Marc. "Système de communication par modulation de phase différentielle de solitons." Phd thesis, Université de Franche-Comté, 2000. http://tel.archives-ouvertes.fr/tel-00519892.
Merolla, Jean-Marc. "Cryptographie quantique par codage en phase de bandes laterales de modulation." Besançon, 1999. http://www.theses.fr/1999BESA2007.
Zhu, Yunlong. "Exploration of Interferometric Detection Methods based on Continuous Phase Modulation." Thesis, Troyes, 2018. http://www.theses.fr/2018TROY0024.
In this thesis, interference signals with continuous phase modulations are theoretically and experimentally analyzed in order to develop cost-efficient solutions for sensing application in mechanics and optics.Several common phase modulation functions and phase retrieval algorithms are presented. We mainly focus on sinusoidal phase modulation (SPM), which is especially attractive for the most accessible modulators (e.g. electro-optical or piezoelectrical modulators). In such case, the demodulation process must handle synchronization issue as well as a possible intensity modulation induced by the SPM. Mathematical solutions are proposed in this context. These demodulation techniques are then applied to three experimental devices developed during this thesis. First of all, a lens-less co-axis digital holography setup has been built, and SPM has been applied for imaging and displacement measurement. Then we use a dual-frequency modulation technique to perform two-dimensional deformation field measurements using an original ESPI (Electronic Speckle Pattern Interferometry) device. This approach allows for simultaneous measurement of the displacement along two different axes using a single laser and a single camera. Finally, we present a compact SPR (Surface Plasmon Resonance) instrument implementing SPM interferometric detection through wavelength modulation, where the amplitude modulation is successfully taken into account
Vu, Thanh-Truc. "Optimisation des propriétés émissives du BODIPY en phase condensée par modulation de la nature des substituants." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2011. http://tel.archives-ouvertes.fr/tel-00718970.
Agnolini, Sébastien. "Contribution à l'étude et à la réalisation d'un système de distribution quantique de clef par codage en phase." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2007. http://pastel.archives-ouvertes.fr/pastel-00003416.
Chaggara, Ridha. "Les Modulations à Phase Continue pour la Conception d'une Forme d'Onde Adaptative Application aux Futurs Systèmes Multimédia par Satellite en Bande Ka." Phd thesis, Télécom ParisTech, 2004. http://pastel.archives-ouvertes.fr/pastel-00000988.
Gutty, François. "Génération d'impulsions solitoniques dans les fibres optiques par instabilité de modulation ou en cavité avec gestion de la dispersion, et caractérisation en intensité et en phase." Dijon, 2001. http://www.theses.fr/2001DIJOS057.
Perlot, Nicolas. "Caractérisation des fluctuations du signal dans les communications optiques par modulation d'intensité et détection directe à travers le canal atmosphérique turbulent." Valenciennes, 2005. https://ged.uphf.fr/nuxeo/site/esupversions/85329049-3099-4b6b-99da-ed87313b72f1.
Laser free-space communications are now able to compete with radio communications. However, optical communications through the atmosphere still suffer from significant drawbacks. In particular, atmospheric optical turbulence, which consists of variations of the refractive index, must be considered as random. Turbulence induces phase and intensity fluctuations in the propagating wave and can cause severe degradations of the system performance. The purpose of this thesis has been to characterize the turbulence-induced fluctuations of the received optical power, also called scintillation. These fluctuations depend on parameters such as the path length, the turbulence strength, the beam shape or the size of the receiving aperture. Theoretical results are derived from the Kolmogorov model of turbulence but different approaches leading to different results are available. Distribution and temporal spectrum of the received optical power serve as inputs to the direct-detection receiver model
Belhache, Franck. "Etude d'un laser à fibre en anneau à gestion de la dispersion avec génération d'impulsions solitoniques, et caractérisation des groupes d'impulsions verrouillées en phase." Dijon, 2003. http://www.theses.fr/2003DIJOS042.
Acco, Pascal. "Etude de la boucle à verrouillage de phase par impulsions de charge : prise en compte des aspects hybrides." Toulouse, INSA, 2003. http://www.theses.fr/2003ISAT0029.
This thesis proposes a study of the stability of the Charge-Pump Phase Locked Loop (CP-PLL). Performances of the transient response of this circuit explains its large use in industrial design. Although the CP-PLL is an hybrid circuit (discrete time part coexists with continuous time parts), signals are represented and analysed by linear models. As there is no others results, stability limits of these linear models are steel used in the industry. Non-linear models can be found in the literature, these models offer high precision results but no analysis tool involving these non-linear models has been proposed. Using hybrid formalism to rewrite non-linear models, we can apply new results on hybrid stability to achieve this first stability proof based on exact waveforms. A piece-wise non-linear model of the CP-PLL can be studied by linearising each non-linear vector field around the fixed point of interest. A theorem is proposed to deduce the local stability of the non-linear system from its linearisation. Stability test is expressed by linear matrix inequalities (LMI). Using the S-procedure to relax conditions in well-chosen region we reduce drastically the conservatism of the sufficient proof. By this way we propose a new stability condition which is less restrictive than linear systems ones. Experimental results tend to confirm this new stability frontier
Ouji, Karima. "Numérisation 3D de visages par une approche de super-résolution spatio-temporelle non-rigide." Phd thesis, Ecole Centrale de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00923192.
Mannah, Marc-Anthony. "Transmission de données par courants porteurs en ligne sur un réseau modulé en largeur d'impulsion." Nantes, 2010. http://www.theses.fr/2010NANT2034.
This thesis studies the use of the Power Line Communication PLC technology in a motor inverter association for purposes of controlling and monitoring. This technology is widely used in domestic applications and allows a reliable communication through the sinusoidal electrical network. In a motor drive application, the electrical network is a Pulse Width Modulation network and consequently this technology may not work. Following a thorough study of the PWM signal, a series of experimental measurements using the domestic PLC modems over the PWM network were carried out and have underlined the inefficiency of the sinusoidal PLC technology. Based on the obtained results and on the PWM network requirements, we have developed industrial PLC couplers. The good functioning of these couplers has been validated in the frequency band 55 MHz – 85 MHz. A study of the required throughput in motor drive applications led us to define the QPSK modulation for data transmission. The modem was developed and communication was tested under different conditions with a throughput equal to 1. 6 Mbits/s. The different experimental measurements have demonstrated the PLC communication feasibility over the PWM network
Diaz, Frédéric. "Systeme d'imagerie hybride par codage de pupille." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00624387.
BAUMLIN, JEAN-MARIE. "Etude de la topographie moire et definition d'une technique de mesure par projection de franges modulees." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13072.
Agnolini, Sébastien. "Contributions à l'étude et à la réalisation d'un système de distribution quantique de clef par codage en phase." Paris 6, 2007. https://pastel.archives-ouvertes.fr/pastel-00003416.
Vacondio, Francesco. "On the benefits of phase shift keying to optical telecommunication systems." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27653/27653.pdf.
The advantages of phase modulation (PM) vis-à-vis intensity modulation for optical networks are accepted by the optical telecommunication community. PM exhibits a higher noise sensitivity than intensity modulation, and it is more tolerant to the effects of fiber nonlinearity. In this thesis we examine the challenges and the benefits of working with different aspects of phase modulation. Our first contribution tackles the complexity of the direct detection noncoherent receiver for differentially encoded quadrature phase shift keying. We examine a novel configuration whose complexity is comparable to that of traditional receivers for intensity modulation, yet outperforming it. We show that under severe nonlinear impairments, our proposed receiver works almost as well as the conventional receiver, with the advantage of being much less complex. We also show that the proposed receiver is tolerant to chromatic dispersion, and to detuning of the carrier frequency. This solution might be suitable for high-bit rates metro (and even access) networks. Our second contribution deals with the challenges of using semiconductor optical amplifiers (SOAs) instead of typical erbium doped fiber amplifiers (EDFAs) to provide amplification to phase modulated signals. SOAs nonlinearities are investigated, and we propose a simple and very effective feed-forward compensator. Above all, the method we propose would permit the integrability of SOAs with other network components (for example, the aforementioned receiver) achieving small size, power efficient sub-systems. Phase modulation paves the way to high spectral efficiency, especially when paired with digital coherent receivers. With the digital coherent receiver, the degree of freedom offered by polarization can be exploited to increase the channel bit rate without increasing its spectral occupancy. In the last part of this work we focus on polarization multiplexed signaling paired with coherent reception and digital signal processing. Our third contribution provides insight on the strategies for upgrading current terrestrial core networks to high bit rates. This is a particularly challenging scenario, as phase modulation has to coexist with previously installed intensity modulated channels. We compare two configurations which have received much attention in the literature. These solutions show comparable performance in terms of back-to-back noise sensitivity, and yet are not equivalent. We show how the superior tolerance to nonlinear fiber propagation (and particularly to cross phase modulation induced by the presence of intensity modulated channels) makes one of them much more effective than the other.
Caussat, Thierry. "Pilotage vectoriel autonome d'une machine asynchrone alimentée par convertisseur statique : autocalibration du variateur de vitesse avant son démarrage : identification en cours de fonctionnement." Toulouse, INPT, 1995. http://www.theses.fr/1995INPT111H.
Boukari, Olfa. "Etude et modélisation des lasers à semiconducteur pour la conception d’un dispositif de mesure par réflectrométrie optique dans le domaine fréquentiel." Rouen, 2007. http://www.theses.fr/2007ROUES037.
Coherent Optical Frequency Domain Reflectometry C-OFDR is used for the characterization of optical components with great dynamic range and sensitivity. This technique requires a coherent tunable laser source with an optical frequency swept linearly. Our work consists in studying the application of semiconductor laser as tunable source, by exploiting the chirp induced by the sawtooth or triangular modulation of the injection current. We characterize, theoretically and in simulation, the linearity and the amplitude of the variation in time of the chirp. The results obtained of the two approaches are in a good agreement. As application we measure, in simulation, Mach-Zehnder interferometer time delay, by using C-OFDR based on DFB laser source under sawtooth and triangular direct modulation. We theoretically calculated the power density of C-OFDR beat signal by taking into account the noise terms, in the case of BH and DFB lasers, deduced from the resolution of laser rate equations
Seck, Aida. "Contribution à l’optimisation des systèmes de transmission optiques cohérents (Nx100 Gbit/s) utilisant le multiplexage en polarisation par des formats de modulation en phase et une conception de ligne limitant l’impact des effets non-linéaires." Thesis, Evry, Institut national des télécommunications, 2014. http://www.theses.fr/2014TELE0008/document.
The ever-increasing demand of capacity in very high bit rate coherent optical transmission systems has paved the way towards the investigation of several techniques such as the use of ultra-low loss fibers, Erbium doped fiber amplifiers, polarization and wavelength division multiplexing (WDM), coherent detection, multi-level modulation formats, spatial division multiplexing, etc. However, there are questions concerning polarization division multiplexing and a development towards some advanced modulation formats including phase modulation and polarization division multiplexing. In this thesis, in order to increase the capacity-by-distance product of future optical coherent systems using wavelength and polarization division multiplexing, we first study spectral shaping of the transmitted signals to increase the information spectral density. For this purpose, we have numerically investigated the multi-channel transmission performance of Polarization Switched Quadrature Phase Shift Keying (PSQPSK) and we have compared it to the performance of Polarization-Division-Multiplexed QPSK (PDM-QPSK), using Root Raised Cosine (RRC) spectral shaping, in the context of a flexible channel grid. In addition we have presented the advantage of PS-QPSK against PDM-QPSK as a function of the system parameters, while we have also discussed the benefit of a RRC spectral shaping against a tight filtering at the transmitter side with a 2nd order super-Gaussian-shaped filter. Furthermore, we have focused on nonlinear effects that limit the transmission distance by degrading the transmitted symbols during propagation. Analyzing and reducing the impact of nonlinear effects is essential when using technologies that increase the information spectral density such as polarization division multiplexing which causes new nonlinear effects due to additional interactions between symbols during the propagation through the fiber. Therefore a reduction of the impact of nonlinear effects is necessary for the development of future systems with higher bit rates of 400 Gbit/s and 1 Tbit/s per channel. We have established in this thesis, design rules to reduce the impact of nonlinear effects in the optical WDM transmission systems at 100 Gbit/s per channel that use polarization multiplexing
Mansouri, Abdelkader. "Le moteur asynchrone monophase à vitesse variable : modélisation et alimentation par convertisseurs statiques." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL096N.
Fang, Jin. "Télécommunications dans les systèmes de transport à forte mobilité : estimation et synchronisation de canal pour les communications MIMO - OFDM." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10042/document.
Numerous wireless communication devices operating in different frequency bands are deployed in the railway domain to answer the multitude of uses and needs, from control and command applications involving safety to non-critical applications (passenger information, video surveillance, on board TV, etc.). These applications are associated with quality of service (QOS) requirements that need estimation techniques and synchronization performance.These communications systems are based on standards that rely on two key technologies: OFDM (Orthogonal Frequency-Division Multiplexing) and MIMO (Multiple-Input Multiple-Output). The combination of MIMO and OFDM permits to benefit from the advantages of both methods. However, the orthogonality between subcarriers of OFDM-MIMO system is destroyed by inter-carrier interference caused by the Doppler effect and frequency offset and phase noise varying between oscillators at transmission and at reception. Thus, the performances of the techniques conventionally used for channel estimation and equalization in a static environment are considerably destroyed in the presence of interference between subcarriers.The purpose of this thesis is to develop new methods and algorithms for estimation and synchronization in very selective channel in time and frequency to allow the evolution of communication systems towards standards that will match better with high speed vehicular communications. It is important to distinguish the case where the propagation channel does not vary during the OFDM symbol duration and when it varies. In this thesis, we focused on the latter.We first developed an algorithm based on the Extended Kalman Filter and the QR decomposition for MIMO-OFDM transmissions. We first approximate the Expansion Model as a basis for temporal variations in complex gains. Our algorithm models the evolution of BEM coefficients within an OFDM symbol by an auto regressive model (AR). Then, we present a normalized frequency offset called normalized CFO in OFDM transmission system that introduces interference between carriers (IEP). This frequency offset is modeled by an AR model. Properties of Extended Kalman filter allow us to estimate simultaneously the two unknown variables, a vector of coefficients, the other BEM normalized frequency offset. The QR algorithm uses a detector to estimate the data symbols. This algorithm presented good performance for receivers at very high speeds. Our second contribution consists of an algorithm that uses the first algorithm to solve the IEP due to phase noise existing in the oscillator of the receiver, and the IEP due to the Doppler effect, but limited to SISO case. Here, we consider that the phase noise has a large variance within one OFDM symbol and also between the two following OFDM symbols. The phase noise is modeled by a Brownian process. Then, the Extended Kalman filter estimates the vector of coefficients of BEM and the vector of phase noise in OFDM symbols. This algorithm is very effective and has a remarkable BER performance when knowledge of the channel and phase noise is poor or nonexistent
Arnal, Maxime. "Gaz quantique dans un potentiel périodique dépendant du temps : de la modulation perturbative aux résonances de l'effet tunnel assisté par le chaos." Electronic Thesis or Diss., Toulouse 3, 2020. http://thesesups.ups-tlse.fr/4689/.
Degenerate quantum gases have demonstrated their ability to mimic the properties of other systems and are, as such, an ideal platform for quantum simulation. These gases, characterized by a high level of control thanks to the temporal driving of their parameters, have mainly been studied either in the perturbative regime or in a purely chaotic one. The aim of the present work is to further extend the possibilities offered by such systems by taking advantage of a mixed dynamics, which we apply to the case of matter-wave transport. In this thesis, we describe several experimental studies on the dynamics of a Bose-Einstein condensate in a one-dimensional time-dependent optical lattice. The experiments that are presented fall into two categories: (i) the perturbative regime, where the applied modulations induce little chaos, and (ii) the mixed regime, where regular and chaotic trajectories coexist at the classical limit. In the perturbative regime, which was first studied during this thesis, we distinguish two modulation domains of the optical lattice. When the modulation frequencies are resonant with the band structure, we induce interband transitions that are subject to selection rules. We then demonstrate a new cooling technique, similar to evaporation but in reciprocal space, taking advantage of these selection rules. For a phase modulation out of resonance, the dynamics of the condensate can be described by an effective Hamiltonian. We study two such Hamiltonians, one of which accounts for a quantum phase transition and the other for the renormalization of the lattice depth. In each case we explore the limits of these models. The mixed regime constitutes the second focus of this thesis. The classical analogue of our system is the modulated pendulum, well-known to present both regular and chaotic trajectories. This behavior is revealed at the quantum level by the presence, in addition to the lattice structure, of a chaotic sea. In this optical lattice dressed by chaos, we study a type of transport called chaos-assisted tunneling, which presents resonances that can amplify or inhibit tunneling between two stable positions within a lattice well. Compared to previous experiments on this subject, we use a different configuration in which we manage to resolve these resonances for the first time. For quantum simulators, this work paves the way to a new type of control, including long-range transport
Andreas, Purwoadi Michael. "Réglage non-linéaire du variateur de vitesse asynchrone sans capteur mécanique : contribution à la commande par la linéarisation exacte entrées-sorties et à l'observation du flux rotorique." Toulouse, INPT, 1996. http://www.theses.fr/1996INPT048H.
Septier, François. "Méthodes séquentielles de Monte-Carlo pour les systèmes multiporteuses en présence de distorsions de phase." Valenciennes, 2008. https://ged.uphf.fr/nuxeo/site/esupversions/f4dcfd51-4eff-4b3f-8b24-72503eeb03de.
Multicarrier transmission systems have aroused great interest in recent years as a potential solution to the problem of transmitting high data rate over a frequency selective fading channel. Nowadays, multicarrier modulation is being selected as the transmission scheme for the majority of new communication systems. However, multicarrier systems are very sensitive to phase noise and carrier frequency offset caused by the oscillator instabilities. In this thesis, a general receiver for compensating the phase distortions effects in multicarrier systems is proposed. Our approach to this non-linear problem is based on Bayesian inference using sequential Monte Carlo filtering also referred to as particle filtering. First, the problem of channel estimation in the presence of phase noise and carrier frequency offset is addressed. Then, a particle filter is proposed to include the joint signal, phase noise and carrier frequency offset estimation. The proposed sequential Monte Carlo filters are efficiently implemented by combining sequential importance sampling, a selection scheme, a variance reduction technique and especially a new on-line parameter estimation based on parallel stochastic expectation maximization algorithms. Moreover in order to improve the estimation accuracy, an original autoregressive modeling of the time-domain multicarrier signal including either pilot or null-subcarriers is also proposed. Extensive simulation study is provided to illustrate the efficiency and the robustness of the proposed algorithms in comparison with those of existing schemes
Labaye, François. "Amplification passive d'un laser à fibre optique dans une cavité Fabry-Perot : application à la production de rayonnement gamma par diffusion Compton inverse." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00837822.
Fourcade, Dutin Coralie. "Réduction de la durée d’impulsions laser par des techniques extra et intra-cavité : post-compression d’impulsions femtosecondes énergétiques et modulation spectrale des pertes dans un pré-amplificateur Ti˸saphir." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14298/document.
High energy ultrashort pulses are highly desirable for many applications. In thismanuscript, we described several methods for pulse duration reduction at high energy. A postcompressionsystem, using SPM-NER in a fused silica plate, has firstly provided 16 fs-5mJpulses, from 50 fs pulses. In a second part, we present a new efficient post compressiontechnique, achieved through ionization of gas in a capillary. With this technique, ultrashortand high energy pulses have been reached (11 fs-13 mJ). Results from modeling done atCEA/SPAM, in good agreement with the experimental ones, have been used to understanddeeply all the involved mechanisms. In order to get even shorter pulses, it is incontrovertibleto work on the laser chain, in front of the post-compression systems. In general, due tospectral gain narrowing in Ti:Saphir laser chain, the pulse duration is limited to 30 fs. Thiseffect, investigated in this thesis, has been compensated by modulating the spectral losses(filter) in the pre-amplifier (regenerative cavity), localized at the gain curve maximum. Pulseduration in the order of 20 fs has been obtained. This study has been completed with a pulseamplification model that shows very good agreement with the experimental measurements.The possibility to combine these processes should generate, in the short term, high energy (10mJ) sub-10 fs laser pulses to produce isolated XUV attosecond pulses
Wang, Kai. "Protéines infectieuses chez la levure Saccharomyces cerevisiae : un mal pour un bien ? Modulation de la propagation de prions de levure par le protéasome et les chaperons moléculaires durant la transition duauxique et la phase stationnaire." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS212/document.
“Proteinaceous infectious particles”, or prions, are self-perpetuating alternate conformations of proteins that are responsible for heritable non-Mendelian traits in mammals, filamentous fungi and yeast. On a more general note, protein misfolding and aggregation is at the origin of over forty protein folding disorders including devastating neurodegenerative diseases such as Alzheimer’s, Parkinson’s or Huntington’s diseases. The aggregated proteins responsible for these diseases (i.e. amyloid-β peptide/tau, α-synuclein and huntingtin) were shown to propagate from cell to cell in a prion-like manner. The yeast Saccharomyces cerevisiae hosts many prion or prion-like proteins, unrelated in sequence and function, which proved to be excellent models for understanding the dynamics of prion aggregation and distribution upon cell division.Sup35p and Ure2p which cause the [PSI+] and [URE3] heritable traits, respectively, stand out as the most studied and best characterized yeast prions to date. A plethora of cellular factors, mostly belonging to various molecular chaperone families, were shown to affect yeast prion formation and propagation. Clearance of protein aggregates and prion particles is however poorly understood and documented. Our laboratory showed that the 26S proteasome degrades both the soluble and prion-associated fibrillar forms of Sup35p. In the first part of my thesis, we investigated the role of the 26S proteasome in the degradation of the soluble and fibrillar forms of Ure2p. We found that, as with Sup35p, the 26S proteasome is able to degrade the soluble native Ure2p, generating an array of amyloidogenic N-terminal peptides and a C-terminal fragment which is resistant to proteolysis. The N-terminal prion domain was shown to act as a degron required for proteasomal engagement and degradation. In contrast to Sup35p, fibrillar Ure2p resisted proteasomal degradation. We expect the structural variability within prion assemblies in a cellular context to dictate their interaction with proteolytic machineries in general and the proteasome in particular.The biology of yeast prions has been mostly explored in the context of logarithmically dividing cells. In nature however, most cells are generally in a post-mitotic non-dividing quiescent state. Yet little is known about the fate and properties of prion particles upon yeast cells entry into the stationary or quiescent states and the physiological consequences of harboring these prions throughout the lifespan of yeast cells. In the second part of my thesis, we addressed this issue using the [PSI+] prion as a model. Structurally different conformers of Sup35p aggregates can lead to distinct [PSI+] strains with different prion phenotypes. We found that Sup35p prion particles undergo growth phase-dependent ultrastructural and functional changes. Indeed, the size distributions of SDS-resistant core-prion particles significantly change during growth without affecting the structural information specific to each prion strain. The infectious properties of Sup35p prion particles undergo dramatic growth phase-dependent changes. Importantly, we found that while [PSI+] has little to no effects on the growth rates of yeasts, it robustly prolongs their chronological lifespan. Furthermore, this beneficial effect can then be permanently and efficiently fixed in the cells even when [PSI+] is subsequently lost. Similar genetic fixation of [PSI+]-induced epigenetic characteristics were previously observed and suggested [PSI+] (and possibly other prions) can act as transient evolutionary capacitators
Maurel, Philippe. "Contribution a l'etude des proprietes physiques des composes ga : :(x)in::(1-x)as::(y)p::(1-y) obtenus par croissance en phase vapeur par la methode des organometalliques." Paris 6, 1987. http://www.theses.fr/1987PA066517.
Wattellier, Benoit. "Amelioration des performances des chaines lasers solides utilisant l'amplification a derive de frequence : nouveaux reseaux de diffraction a haute tenue au flux et mise en forme programmable de faisceaux lasers par modulation de la phase spatiale." Palaiseau, Ecole polytechnique, 2001. http://www.theses.fr/2001EPXX0027.
Mohammedi, Merah Mounir. "Conception et réalisation d’un lien Light-Fidelity multi-utilisateur en intérieur." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLV061/document.
Nowadays, the number of connected devices requiring access to mobile data is considerably increasing. The arrival of even more connected multimedia objects and the growing demand for more information per device highlighted the limits of the fourth generation of broadband cellular networks (4G). This pushed for the development of new methods, one of which is 5G. The goal is to be able to support the growth of wearable, sensors, or related internet-of-object (IoT) systems. The vision behind 5G is to enable a fully mobile and connected society with a consistent experience. In consequence, there is a fundamental need to achieve a seamless and consistent user experience across time and space.Small cells are the basis of advanced communications standards such as 4G and now, 5G. They exist as a result of using higher frequency bands for RF access in order to support new standards and the increasing demands in bandwidth. 5G use millimeter waves and requires a deployment across indoor and dense urban environment which may prove to be a challenge. This is where 5G will need to include hybrid networking solutions and be able to coexist with other wireless access technologies. Visible light communication (VLC) fits into that mold since visible light corresponds to the band between 400 and 800 THz. The available spectrum is multiple thousand times the size of the RF spectrum and it does not interfere with it. The technique combines illumination with communication at possibly tens of gigabits per second. It has the potential to offer a synergistic pairing with 5G in a hybrid network, offering high speed, no interferences, and more security at the cost of limited coverage and low technological maturity.The goal of this thesis is thus to propose and evaluate an experimental implementation of an indoor multi-user VLC system in order to answer the objectives of Li-Fi setup in the context of a small cell. The first step of this study is a detailed state-of-the-art on VLC in indoor wireless communication and multi-user access. It allows the design of our work to be better explained and to compare our approach with existing works. The second step is an analysis of the principles and hypothesis supporting the indoor multi-user VLC system in the study both on the modulation technique and the multi-user access schemes. The conclusions drawn from theoretical and numerical analysis are used as a basis for the rest of the work. The third step is the experimental setup investigations on the single-user broadcast performances optimization and then on the multi-user performances of the system using various schemes. The total throughput using an off-the-shelf white LED reaches 163 Mb/s with a bit-error rate decreased by a factor of 3.55 thanks to the performance optimization process. This technique has the advantage of increasing the flexibility for a multi-access scenario while not augmenting the complexity as it only optimizes the modulation filter parameters. The multi-user access is obtained for a cell size of 4.56 m² at a distance of 2.15 meter away from the transmitter. The user capacity can reach up to 40 users, or 40.62 Mb/s in a 4-user scenario. It is thus demonstrated that the proposed system could function as a cell at a realistic range, with high data rate and the ability to provide for a large amount of users while limiting the cost of implementation
Perrin, Stephane. "Development and characterization of an optical coherence tomography micro-system : Application to dermatology." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2002/document.
The manuscript concerns the optical design and the development of a non-invasive new imagingsystem for the early diagnosis of skin pathologies. Indeed, an early diagnosis can make the differencebetween malignant and benign skin lesion in order to minimize unnecessary surgical procedure.Furthermore, prognosis for the year 2015 was that more than three millions new skin cancer caseswill be diagnosed in the United States. Based on the swept source optical coherence tomographytechnique in full-field and multiple channels configuration, the imaging system is able to perform avolumetric image of the subsurface of the skin, and thus can help in taking a better medical decision.Furthermore, for a batch-fabrication of the hand-held device, micro-optical components were made atwafer-level and vertically assembled using multi-wafer bonding. This miniaturized system requiresspecific characterization. Thus, two systems were also developed for imaging quality evaluation ofmicro-optical elements. This work has been supported by the VIAMOS (Vertically Integrated ArraytypeMirau-based OCT System) European project
Hou, Yingfan. "Apport de la combinaison de méthodes de mesure de formes tridimensionnelles dans le contexte de l'endoscopie flexible." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2255/document.
The techniques of three dimensional shapes reconstruction are widely used in many fields, particularly in the industrial or medical field. And in these areas, non-contact measurement techniques are particularly studied, mainly because they don't damage the measured object. This work therefore falls within this context and in particular in the case of endoscopic devices of surface coordinate measuring by optical methods. ln the medical field, this type of instrument can be applied to 3D colonoscopy or minimally invasive surgery to the surface in the form of biological tissues. In this thesis, methods based on active or passive stereo vision are the principle, which will be studied and integrated into a miniaturized device. Different measurement modes will be incorporated simultaneously into a single miniaturized instrument to help increase measurement performance: the instrument can adjust its measurement principle to the texture of the object or also to the orientation of measured surfaces more generally to the context of the measurement. This thesis is based on an algorithmic study and instrumental integration of these different measurement modes into a single miniaturized endoscopic instrument. The study of the measurement modes stereovision was conducted in three phases. First, it is the influence of the orientation of the measured objects' surface in a case of active stereovision being analyzed. And a technique of switching between the projection and acquisition in an active stereovision system by bistable actuation is proposed, which allows to adapt the measurement to the orientation of the measured surfaces. Finally, the study is oriented towards the ability to switch from one active stereovision mode to one passive stereovision mode, always by bistable actuator operation, the passive stereovision mode is particularly suitable for highly textured objects. Thus, three measurement modes are made in the new system: two modes of active stereovision (reversing capture and projection channels) and a mode of passive stereovision. To achieve three-dimensional reconstruction, two active methods (phase shift and Fourier Transform) and a passive method are studied. Different performance measurements are obtained according to methods selected: a more accurate measuring result is obtained by the phase shift methods; a high measurement speed is obtained by the Fourier transform methods or by passive methods. The instrumental development is also described in this thesis. After optical modeling and mechanical design of the measuring system, a prototype of the endoscopic instrument is manufactured with various specific devices such as a DMD (Digital Micromirror Deviee),images guides and bistable electromagnetic actuators. The experimental validation of the three-dimensional measurement is performed mainly on mechanical objects (such as details measurement on a coin), both active and passive method methods are well tested and compared. Finally, an artificial colon is measured by this system to be placed in a medical application context
Khaleghi, Hamidreza. "Influence des amplificateurs optiques à semi-conducteurs (SOA) sur la transmission cohérente de signaux optiques à format de modulation multi-porteuses (CO-OFDM)." Phd thesis, Université de Bretagne occidentale - Brest, 2012. http://tel.archives-ouvertes.fr/tel-00829663.
Hernández, Cubero Óscar Rubén. "Méthodes optiques innovantes pour le contrôle rapide et tridimensionnel de l’activité neuronale." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB005.
The ongoing revolution of optogenetic tools – genetically encoded light-sensitive proteins that can activate, silence and monitor neural activity – has opened a new pathway to bridge the gap between neuronal activity and cognition. However, to take full advantage of these tools we need optical methods that can deliver complex light patterns in the brain. During my doctorate, I worked on two novel and complementary optical systems for complex spatiotemporally neural activity stimulation. The first system combined acousto-optic deflectors and low numerical aperture Gaussian beam illumination for fast photoactivation of optogenetic tools. The random-access capabilities of the system allowed to deliver complex spatiotemporal illumination sequences that successfully emulated physiological patterns of cerebellar mossy fiber activity in acute slices. These results demonstrate that patterned optogenetic stimulation can be used to recreate ongoing activity and study brain microcircuits in a physiological activity context. Alternatively, Computer Generated Holography (CGH) can powerfully enhance optogenetic stimulation by efficiently shaping light onto multiple cellular targets simultaneously. Nonetheless, the axial confinement degrades for laterally extended illumination patterns. To address this issue, CGH can be combined with temporal focusing that axially confines fluorescence regardless of lateral extent. However, previous configurations restricted nonlinear excitation to a single spatiotemporal focal plane. In this thesis, I describe two alternative methods to overcome this limitation and enable three-dimensional spatiotemporal focused pattern generation
Nguyen, Trung-Hiên. "Theoretical and experimental study of optical solutions for analog-to-digital conversion of high bit-rate signals." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S110/document.
Bi-dimensional modulation formats based on amplitude and phase signal modulation, are now commonly used in optical communications thanks to breakthroughs in the field of electronic and digital signal processing (DSP) required in coherent optical receivers. Photonic solutions could compensate for nowadays limitations of electrical circuits bandwidth by facilitating the signal processing parallelization. Photonic is particularly interesting for signal sampling thanks to available stable optical clocks. The heart of the present work concerns analog-to-digital conversion (ADC) as a key element in coherent detection. A prototype of linear optical sampling using an original solution for the optical sampling source, is built and validated with the successful equivalent time reconstruction of NRZ, QPSK and 16-QAM signals. Some optical and electrical limitations of the system are experimentally and numerically analyzed, notably the extinction ratio of the optical source or the ADC parameters (bandwidth, integration time, effective number of bits ENOB). Moreover, some new DSPs tools are developed for optical transmission using bi-dimensional modulation formats (amplitude and phase). Two solutions are proposed for IQ quadrature imbalance compensation in single carrier optical coherent transmission: an original method of maximum signal-to-noise ratio estimation (MSEM) and a new structure for joint compensation and equalization; these methods are experimentally and numerically validated with 16-QAM signals. Moreover, an improved solution for carrier recovery (frequency offset and phase estimation) based on a circular harmonic expansion of a maximum loglikelihood function is studied for the first time in the context of optical telecommunications. This solution which can operate with any kind of bi-dimensional modulation format signal is numerically validated up to 128-QAM. All the DSP tools developed in this work are finally used in a demonstration of a 10 Gbaud QPSK 100 km transmission experiment, featuring a strong non-linear phase noise limitation and regenerated using a phase preserving and power limiting function based on a photonic crystal nanocavity
Voineau, Florian. "Systèmes communicants haut-débit et bas coûts par guide d’ondes en plastique." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0178/document.
In a world willfully transitioning to the Digital Age, the thirst for connectivity demands high-speed communication links at low cost. In this context, affordable plastic waveguides have been proposed as a disruptive propagation channel in the millimeter-wave (mmW) range. Benefiting from multi gigahertz (GHz) bandwidths and mmW capabilities of advanced CMOS technologies as well as relaxed assembly tolerances requirements, cost-effective communication systems based on plastic waveguides could offer multi gigabits per second (Gb/s) data rates over several meters distances.In this work, the design of plastic waveguide channels is first discussed using both a theoretical approach and Electromagnetic (EM) simulations. Although low attenuation promises have been confirmed, some limitations are also highlighted, especially as regards confinement ability and robustness to external contacts. Solutions involving foam coating are briefly investigated and an innovative plastic waveguide design demonstrating improved characteristics is introduced.System-level topics are then explored in order to build a communication system using the previously presented channel. A new architecture, which combines Quadrature Phase Shift Keying (QPSK) and frequency multiplexing, is found to be much more suitable. The transition from the circuit to the plastic waveguide has also been identified as a potential bandwidth bottleneck. Consequently, a wideband microstrip to WR-12 transition has been designed. Another limitation concerning the demodulation of QPSK mmW signals is investigated and an original topology using the non-linearities of Injection Locked Oscillators (ILO) has been developed.Finally, the design of a mmW transmitter in an advanced silicon technology node (CMOS 28 nm FD-SOI) is described. Major contributions include the introduction of high-performance integrated hybrid couplers and the realization of a wide locking range synchronization circuit enabling low phase-noise operation when locked on the fifth harmonic of a reference signal. Measurements on modulated signals have validated the transmitter high data-rate capability of several Gb/s
Jerbi, Ghada. "Design d’un système d’une tomographie par cohérence optique sensible à la polarisation." Thèse, 2018. http://hdl.handle.net/1866/21371.
Grégoire, Pascal. "Étude de semi-conducteurs par spectroscopie d'excitation cohérente multidimensionnelle." Thèse, 2017. http://hdl.handle.net/1866/20602.