This diploma thesis is focused on design and prototyping of wireless optical link for an indoor usage. In the beginning of the thesis frequency spectrums of infrared, visible and ultraviolet light are described by its typical qualities such as values of attenuation or reflection capability. On the basis of this analysis, a proper wavelength has been chosen for usage at the engineered communication system. Next part is devoted to selection of suitable communication components on basis of its declared qualities. In the following chapter this qualities are in carefully measured and after that they are compared with values provided by its manufacturer. The following section is devoted to design schemes of transceiver modules. After completion of the design the manufacturing of PCB, mounting components and the analysis of their distribution was described. The last part of this thesis deals with testing of created prototype in terms of maximum transmission distances and operating frequencies. At the very end of this project, in one small section ways to improve system characteristics was discussed.

The diploma thesis deals with description and design of a low-cost free-space optical (FSO) link. First, general FSO theory is discussed including their common parameters, properties and topologies. Further, optical signal sources and detectors are proposed. Finally, the selected implementation is described including its design and realization. The proposed FSO consists of two identical segments (modules) to form a full-duplex link. The FSO utilizes LED as a light source, maximum speed data rate is 100 Mb/s with 100Base-TX interface.

The aim of the study was focused on problem of electrograms recording with using voltage sensitive dyes. Study of electrograms recording was extended with thema of optical detectors suitable for measurement and noise analysis. Elimination of noise and disturption was made in program Matlab; lowpass filtration and wavelet transformation was used. Application for electrograms analysis was developed in latter part of this work.

This diploma thesis deals with an analysis of the method of propagation of optical fiber by two polarization planes. The method of light propagation is mathematically described using Jones and Stokes vectors. The first part describes wave theory of light divided by Fresnel wave theory, polarization ellipse, degenerate polarization states, parameters of polarization ellipse, Poincaré sphere and degenerated states on Poincaré sphere. Then follows Stokes and Jones polarization parameters, their vectors and Mueller matrix. In addition this paper illustrates the principle of the temperature sensor which is carried out with the help of the polarimeter and its computer program. The following is design of temperature sensor, which is composed of polarizer, photodiode, light output meter and digital multimeter. Another part of the thesis shows the measured values using the current measurement solution using polarimeter and proposed photodiode sensor. At the end of the thesis there is a comparison of the measured values for the three different temperatures that were applied to the optical fiber.

This thesis presents the modeling and fabrication of a new solid-state device meant to be used for digital logic circuits. Most current logic circuits are based on MOSFETs. The new logic device uses some of the same operating principles, but also relies on optical illumination to provide input power. In order to obtain the desired current-voltage behavior of the new device, the Silvaco (Atlas) device simulation was used to give some insight into the correct doping levels in the semiconductor and device geometries. Prototypes were fabricated on p-type silicon wafers using CMOS fabrication processes including oxide growth, photolithography, precise plasma or chemical wet etching, diffusion processes, and thin film evaporation. Electrical measurements were done by using an HP4156 parameter analyzer to measure several output voltage signals at one time while an illuminating the device with laser light. The current-voltage characteristics under different biasing conditions with an optical illumination condition were measured and showed characteristics similar to an nMOS transistor.

As one of the more mature quantum technologies, quantum random number generators (QRNGs) fill an important role in producing secure and private keys for use in cryptogra- phy in e.g. quantum key distribution (QKD) systems. Many available QRNGs are expen- sive and optical QRNGs often require complex optical setups. If a reliable QRNG could be implemented using less expensive components they could become more widespread and be used in common applications like encryption and simulation. Shot noise is a possible entropy source for these kinds of random number generators. For such a generator to be classified as a QRNG the origin of the shot noise must be controlled and verifiable. This project aims to investigate how an entropy source could be implemented using the shot noise generated by an illuminated photodiode. This requires the design and construction of the accompanying electro-optical front-end used to prepare a signal for sampling. The successful estimation of the electron charge e is used as a way to verify that shot noise is present in the sampled signal. Suitable component values and operating points are also in- vestigated and it is shown that quite low gain (10 000) is suitable for the current-to-voltage amplifier which amplifies the signal generated by the photodiode. For this configuration an estimate of e was achieved with a relative error of 3%. In conclusion this is a promising and interesting approach for generating random numbers at high rates and at low cost. Whether the correct estimation of e is enough to certify that the device is sampling noise from the quantum regime is however not completely clear and further investigation is likely needed.

Les imageurs CMOS représentent un outil d’avenir pour de nombreuses applications scientifiques de haut vol, tellesque l’observation spatiale ou les expériences nucléaires. En effet, ces imageurs ont vu leurs performancesdémultipliées ces dernières années grâce aux avancées incessantes de la microélectronique, et présentent aussi desavantages indéniables qui les destinent à remplacer les CCDs dans les futurs instruments spatiaux. Toutefois, enenvironnement spatial ou nucléaire, ces imageurs doivent faire face aux attaques répétées de particules pouvantrapidement dégrader leurs performances électro-optiques. En particulier, les protons, électrons et ions présents dansl’espace ou les neutrons de fusion nucléaire peuvent déplacer des atomes de silicium dans le volume du pixel et enrompre la structure cristalline. Ces effets de déplacement peuvent former des défauts stables introduisant des étatsd’énergie dans la bande interdite du silicium, et ainsi conduire à la génération thermique de paires électron-trou. Parconséquent, ces radiations non-ionisantes produisent une augmentation permanente du courant d’obscurité despixels de l’imageur et donc à une diminution de leur sensibilité et de leur dynamique. L’objectif des présents travauxest d’étendre la compréhension des effets de déplacement sur l’augmentation du courant d’obscurité dans lesimageurs CMOS. En particulier, ces travaux se concentrent sur l’étude de la forme de la distribution de courantd’obscurité en fonction du type, de l’énergie et du nombre de particules ayant traversé l’imageur, mais aussi enfonction des caractéristiques de l’imageur. Ces nombreux résultats permettent de valider physiquement etexpérimentalement un modèle empirique de prédiction de la distribution du courant d’obscurité pour une utilisationdans les domaines spatial et nucléaire. Une autre partie majeure de ces travaux consiste à utiliser pour la première foisla technique de spectroscopie de courant d’obscurité pour détecter et caractériser individuellement les défautsgénérés par les radiations non-ionisantes dans les imageurs CMOS. De nombreux types de défauts sont détectés etdeux sont identifiés, prouvant l’applicabilité de cette technique pour étudier la nature des défauts cristallins généréspar les effets de déplacement dans le silicium. Ces travaux avancent la compréhension des défauts responsables del’augmentation du courant d’obscurité en environnement radiatif, et ouvrent la voie au développement de modèles deprédiction plus précis, voire de techniques permettant d’éviter la formation de ces défauts ou de les faire disparaître. / CMOS image sensors are envisioned for an increasing number of high-end scientific imaging applications such asspace imaging or nuclear experiments. Indeed, the performance of high-end CMOS image sensors has dramaticallyincreased in the past years thanks to the unceasing improvements of microelectronics, and these image sensors havesubstantial advantages over CCDs which make them great candidates to replace CCDs in future space missions.However, in space and nuclear environments, CMOS image sensors must face harsh radiation which can rapidlydegrade their electro-optical performances. In particular, the protons, electrons and ions travelling in space or thefusion neutrons from nuclear experiments can displace silicon atoms in the pixels and break the crystalline structure.These displacement damage effects lead to the formation of stable defects and to the introduction of states in theforbidden bandgap of silicon, which can allow the thermal generation of electron-hole pairs. Consequently, nonionizingradiation leads to a permanent increase of the dark current of the pixels and thus a decrease of the imagesensor sensibility and dynamic range. The aim of the present work is to extend the understanding of the effect ofdisplacement damage on the dark current increase of CMOS image sensors. In particular, this work focuses on theshape of the dark current distribution depending on the particle type, energy and fluence but also on the imagesensor physical parameters. Thanks to the many conditions tested, an empirical model for the prediction of the darkcurrent distribution induced by displacement damage in nuclear or space environments is experimentally validatedand physically justified. Another central part of this work consists in using the dark current spectroscopy techniquefor the first time on irradiated CMOS image sensors to detect and characterize radiation-induced silicon bulk defects.Many types of defects are detected and two of them are identified, proving the applicability of this technique to studythe nature of silicon bulk defects using image sensors. In summary, this work advances the understanding of thenature of the radiation-induced defects responsible for the dark current increase in space or nuclear environments. Italso leads the way to the design of more advanced dark current prediction models, or to the development ofmitigation strategies in order to prevent the formation of the responsible defects or to allow their removal.

Ce travail porte sur la conception, la fabrication et la caractérisation d’une photodiode très haut débit (UTC PD) et son intégration avec un préamplificateur optique à semi-conducteur (SOA) pour les liaisons optiques à courte distance à 100 Gbit/s en bandes C et O. Il porte également sur la conception d'un duplexeur (Tx / Rx) avec liaison montante en bande C et liaison descendante en bande O. L'intégration monolithique d’un SOA avec une photodiode haut débit sans filtre optique entre les deux présente des avantages majeurs parmi lesquels: - Augmentation de la distance de transmission. - Augmentation du nombre d'utilisateurs connectés. - Diminution des coûts globaux de fabrication incluant l’assemblage. La première partie de cette étude porte sur l'optimisation SOA pour un fonctionnement à forte puissance (Psat). Un faible facteur de bruit (NF) et une faible dépendance à la polarisation (PDL) sont requis pour les récepteurs préamplifiés. De plus, un fonctionnement du et opérer en régime linéaire est nécessaire pour les schémas de modulation complexes. Le SOA actuel possède un gain de 18 dB avec un facteur de bruit de 8 dB, une faible PDL (<2 dB), et une bonne puissance de saturation en entrée (-8 dBm). Grâce à l’optimisation de la structure verticale du SOA et de son couplage avec la fibre les performances attendues sont améliores : Psat >-5 dBm, NF <8 dB, PDL et gain similaire. D'autre part, les interconnexions électriques de la photodiode ont été optimisées ce qui a permis de démontrer des photodiodes avec une bande passante supérieure à 100 GHz. Les photodiodes présentent un fort coefficient de réponse (R) (0,6 A/W à 1,3 μm et 0,55 A/W à 1,55 μm) et une faible PDL <1 dB. Un fort courant de saturation de 14 mA à 100 GHz a aussi été démonté. Enfin, la caractérisation des SOA-UTC réalisés a montré simultanément une très forte responsivité (95 A/W), une faible dépendance à la polarisation PDL (<2 dB), un faible NF (8 dB) et une large bande passante à 3 dB (> 95 GHz), qui placent nos composants au meilleur niveau de l’état de l’art avec un produit gain-bande record de 6,1 THz. Les Mesures numériques à 64 Gbit/s montrent que notre récepteur atteint une sensibilité de -17 dBm pour un taux d'erreur de 10-9, et la sensibilité attendue à 100 Gbit/s est de -14 dBm / This work focuses on the design, fabrication and measurements of a uni-travelling carrier high speed photodiode (UTC PD) and its integration with a semiconductor optical preamplifier (SOA) for short reach 100 Gbit/s optical links, in O- and C- bands. This work also focuses on the design of a duplexer (Tx/Rx) with downstream in O-band and upstream in C-band. The SOA monolithic integration with a high speed PD without an optical filter in between yields major benefits among which: - Increase in the transmission distance. - Increase in the split ratio correlated to the number of connected users. - Decrease of the overall fabrication and assembling cost. The first part of this work is dedicated to optimizing the SOA for high power operation (Psat). The low noise figure (NF), and polarization dependence loss (PDL) are critical parameters for a preamplified receiver. Also complex modulation formats require linear gain regime of the SOA. The current SOA presents 18 dB gain with NF (8 dB), low PDL (<2 dB), and good input power saturation (-8 dBm). Thanks to further optimization of the SOA vertical structure and coupling with the optical fiber, the expected SOA performance is higher Psat >-5 dBm, NF <8 dB, similar PDL and gain. Secondly, the electrical interconnects of the photodiode is optimized to increase the photodiodes’ bandwidth, which allows to demonstrate photodiode with >100 GHz bandwidth. The PD presents high responsivity (R) (0,6 A/W at 1,3 μm and 0.55 A/W at 1,55 μm) and low PDL <1 dB. Also the saturation photocurrent is high (14 mA at 100 GHz). Finally, the SOA-UTC demonstrates high responsivity (95 A/W), low PDL (<2 dB), low NF (8 dB) and a wide 3 dB bandwidth (>95 GHz), which yields a record gain-bandwidth product of 6.1 THz. Large signal measurements at 64 Gbit/s show that our receiver reaches a low sensitivity of -17 dBm for a bit error rate of 10-9, and is expected to reach -14 dBm at 100 Gbit/s

This thesis presents novel materials for photovoltaic conversion. The materials described are solution-processable organic semiconductors and have been used in the fabrication of organic photovoltaic cells (OPVs). The widely used PEDOT:PSS layer was investigated in P3HT and PTB7 photovoltaics. By doping, the efficiencies recorded were amongst the highest reported in the field using a conventional architecture. Two low band-gap BODIPY-based polymers were introduced and shown to have properties favourable for optoelectronics. Photovoltaics consisting solely of the polymers as the active component surpassed the performance expected without the use of an acceptor, indicating ambipolar behaviour, which was verified by charge carrier mobility measurements. When blended with an acceptor, the devices demonstrated a short-circuit current density similar to that of P3HT, a well-studied and successful OPV material. They also revealed a broad spectral response and were shown to operate as photodiodes. Two small molecules containing diketopyrrolopyrrole (DPP) and BODIPY were introduced and characterised. The addition of thiophenes red shifted the absorption but did not result in a sufficient bathochromic shift. Instead, a propensity to aggregate limited the performance. PLQY measurements showed the aggregation to quench luminescence. The study demonstrated the importance of controlling aggregation for efficient devices. Two solution-processable small molecules with a germanium-bridged spiro centre were investigated, and the molecular, electrochemical and optical properties discussed. The small molecule with shorter conjugation length exhibited an interesting packing motif shown to be favourable for charge transport. The mobility measurements were an order of magnitude higher than those reported for sexithiophene, a small molecule analogue, and the same order of magnitude as P3HT. The two-dimensional charge transporting nature of the material was verified with two independent techniques: time of flight (TOF) and organic field-effect transistor (OFET) measurements. The mobility of the material was found to vary with annealing, a result of morphological changes. These were studied with optical, electron and scanning probe microscopies. By controlling the morphology with the implementation of a well-defined annealing method, it was possible to improve the performance of OFETs and planar-heterojunction OPVs. Solution-processed bulk-heterojunction OPVs were fabricated, characterised and optimised with Ge spiro molecules. A PCE similar to that of P3HT, 2.66 %, was achieved for the one, whilst a PCE of 1.60 % was obtained for the other. The results are encouraging, and there is scope for improvement by increasing the overlap between the absorption and solar spectrum, for example.

L'intégration optoélectronique d'un récepteur dans une transmission sur fibre optique concerne l'assemblage de trois principales fonctions : la photodétection, la récupération d'horloge et la régénération des données. Cette thèse contribue au développement d'un tel concept avec, d'une part, l'étude d'une structure de photodiode appelée UTC (Uni-Travelling Carrier) compatible avec le transistor bipolaire à double hétérojonction (TBdH), et d'autre part, la réalisation dans cette même technologie TBdH d'un oscillateur commandé en tension ou VCO (Voltage-Controlled Oscillator) pour la récupération d'horloge et des données à 40 et 43 Gbit/s. La photodiode UTC présente de très bonnes performances en bande passante et en courant de saturation par rapport à la photodiode PIN classique. La première partie de ce travail présente une étude approfondie de la structure UTC ainsi que son intégration avec la structure TBdH sur substrat InP. La compatibilité entre ces deux structures a été validée avec quelques critères à respecter. En particulier, le dopage et l'épaisseur de la base constituent les principaux compromis entre la sensibilité et la rapidité du dispositif. Le VCO de type différentiel permettra, après intégration dans une boucle à verrouillage de phase ou PLL (Phase-Locked Loop), de générer un signal stable fournissant deux phases d'horloge complémentaires aux circuits numériques, notamment au circuit de décision utilisé pour la régénération des données. L'architecture « à varactor interne » choisie offre un fort potentiel pour la réalisation des VCO de très hautes fréquences. Le circuit VCO réalisé au cours de cette thèse présente de bonnes performances en plage d'accord (10%) autour de la fréquence d'oscillation de 45 GHz. La précision de cette fréquence est liée aux modèles du transistor et de la ligne coplanaire utilisés dans la simulation, ainsi qu'à la reproductibilité technologique. Ces résultats permettent de franchir une étape importante et nécessaire à la réalisation d'un récepteur monolithique à base de TBdH InP pour les applications à très haut débit.