Envisioning novel fully monolithic fiber-optical devices, this dissertation investigates four fiber optical devices both, active and passive, that contribute to the goal of further integrating and miniaturizing fiber optics. An all phosphate glass fiber laser was designed in an effort to reduce laser intensity noise by reducing cavity losses and low mechanical strength that arise from intra-cavity fusion splices between silica fiber Bragg gratings (FBG) and phosphate active fiber in state of the art phosphate single frequency fiber lasers. Novel phosphate glass based FBGs have been fabricated utilizing high intensity laser pulses at 193 nm and a phase-mask. Net reflectivities of up to 70 % and a bandwidth of 50 pm have been achieved in the FBGs. The laser design comprised two of the novel FBGs and a short section of Er³⁺Yb³⁺ phosphate fiber to form a distributed Bragg reflector (DBR) laser. The performance of the new laser has been compared to a conventional phosphate fiber laser. Particular focus was put on the laser intensity noise due to its dependence on intra-cavity losses. Relative intensity noise (RIN) amplitudes of -80 dB/Hz have been measured for both lasers when operating at comparable output powers. For similar levels of absorbed pump power the relaxation oscillation frequencies (ROF) were shifted towards lower frequencies in the new laser. ExcessFBG scattering losses and mode-field miss-match between the active and passive fiber limited the output power of the new laser to 16 mW compared to 140 mW in the conventional laser. A monolithic all-phosphate glass fiber laser with up to 550 mW output power that is operating at a single longitudinal mode and exhibiting narrow linewidth is presented. The laser cavity has been formed by inscribing FBGs directly into heavily Er³⁺Yb³⁺ doped phosphate glass fiber using femtosecond laser pulses and a phase mask, completely eliminating the need for intra-cavity fusion splices. A linewidth of less than 60 kHz and relaxation oscillation peak amplitudes below -100 dB/Hz without active suppression of RIN have been measured. The compact form factor and higher output power combined with the low noise and narrow linewidth characteristic make this laser an ideal candidate for ranging, interferometry and sensing applications. Strong and robust Bragg gratings in optical fiber fabricated from highly photosensitive photo-thermo-refractive (PTR) glass are demonstrated. The fibers were drawn at 900 °C from a machined PTR-glass preform. A low power two beam interference pattern from a continuous wave (cw) He-Cd laser with a wavelength of 325 nm was used to write gratings into the fibers, achieving peak grating strengths of 20 dB and a spectral width of 45 pm. The gratings showed no sign of degradation when exposed to a high temperature environment of 425 °C for several hours. This is significantly higher when compared to standard Telecom FBGs which are rated for operation temperatures below 200 °C. A detailed study of novel mode-field adapters (MFA) based on multi-mode interference in graded index multi-mode fibers (GIMF) is presented. MFAs are often used in cases when low coupling losses between single mode fibers with very different mode-field diameters are needed. Here a new type of MFAs has been fabricated and characterized from a selection of commercially available single mode and graded index fibers. Compared to existing techniques the presented MFAs can be fabricated very quickly and are not limited to certain fiber types. Insertion losses of 0:5 dB over a spectral range of several hundred nm have been obtained with an ultra compact MFA with a length of 275 μm.

Dans cette thèse, des réseaux de nano- et micro-capteurs électrochimiques et opto-électrochimiques sont fabriqués en utilisant la technique de microfabrication « template synthesis ». Dans une première partie, des ensembles de nanoélectrodes (NEEs) sont utilisés comme plate-forme pour obtenir un biocapteur. Les NEEs sont préparés par déposition d’or dans une membrane poreuse en polycarbonate. L’originalité de notre approche a été de modifier la membrane de polycarbonate entourant les NEEs et non les NEEs elles-mêmes. La peroxydase de raifort (HRP) qui est fixée sur un anticorps secondaire a servi comme marqueur. Cette enzyme catalyse la réduction de H2O2 qui est ajouté en solution. En utilisant un système de détection dérivé de l'approche ELISA (Enzyme- Linked Immuno-Sorbants Assay), le récepteur de la protéine HER2 a été pris comme analyte cible. Il s’agit d’une protéine très importante puisqu’elle permet de dépister le cancer du sein. Dans une seconde partie, un réseau ordonné de sondes opto-électrochimiques est développé sur la face distale d’un faisceau de fibres optiques qui a été attaquée sélectivement par voie humide. Une structure macroporeuse est fabriquée en utilisant un cristal colloïdal comme « template ». L’or est ensuite déposé dans les interstices avant de dissoudre les nanoparticules de latex formant le cristal colloïdal. Ce réseau de microcavités macroporeuses a été testé avec succès comme substrat pour des mesures de Raman exalté de surface (SERS). / In this thesis, arrays of nano- and microelectrodes are developed to obtain electrochemical and optoelectrochemical sensors, by using the template synthesis as a microfabrication technique. In the first part, ensembles of nanoelectrodes (NEEs), obtained using a track-etched polycarbonate membrane as template, are functionalised in order to obtain electrochemical immunosensors. A biorecognition chain, antigen-antibody, is immobilized on the wide polycarbonate membrane letting uncovered the gold nanodisk electrodes. A label redox enzyme, linked to the biorecognition chain, is recognized and quantified electrochemically. Two different detection schemes are developed and low protein detection limits are achieved. In the second part, a macroporous micrometer sized opto-electrochemical sensor is developed on the distal face of an imaging fiber (coherent optical fiber bundle). A microwell array is obtained by controlled chemical etching, by exploiting the different chemical composition between cores and clads. Colloidal templates are created inside the microcavities, using polystirene beads of 280 nm. Gold is deposited inside the cavities, filling the void in the colloidal template, exploiting electroless and electrochemical deposition techniques. The gold macroporous structure inside the wells is successfully tested as SERS substrate.

O desenvolvimento da fotônica integrada vem recebendo muita atenção nos últimos anos. Sua alta funcionalidade e velocidade de transmissão de sinais possibilitam a aplicação em diversas áreas, que vão desde comunicações até biologia. O uso de polímeros em circuitos fotônicos integrados tem se mostrado interessante, pois compostos orgânicos podem ser facilmente incorporados a matrizes poliméricas. Isso faz com que as propriedades físicas do polímero possam ser modificadas de acordo com os materiais incorporados. Além disso, a técnica da fotopolimerização por absorção de dois fótons torna possível a produção de microestruturas poliméricas tridimensionais com alta resolução. A incorporação dessas microestruturas a circuitos fotônicos pode trazer um novo ramo de funcionalidades devido à facilidade de modificação das propriedades dos polímeros. Além disso, a tridimensionalidade das estruturas permite a realização de conexões ópticas em três dimensões, o que colabora para o aumento da compacticidade dos dispositivos fotônicos. No entanto, para que estas microestruturas possam ser efetivamente incorporadas aos circuitos fotônicos é necessário desenvolver formas de conectá-las a fontes externas de excitação, bem como a instrumentos de análise de sinais. Os tapers de fibras ópticas, também conhecidos como microfibras ou nanofibras, são bons candidatos para realizar essa tarefa devido a suas dimensões reduzidas, as quais são compatíveis com o tamanho das microestruturas. Neste trabalho desenvolvemos métodos para realizar a conexão óptica entre microestruturas poliméricas e tapers de fibras ópticas. As microestruturas foram produzidas através da técnica de fotopolimerização por absorção de dois fótons e corantes orgânicos foram incorporados à matriz polimérica para conferir propriedades fluorescentes às estruturas. Os tapers foram produzidos a partir de fibras ópticas convencionais por uma técnica de aquecimento e estiramento. Para realizar a conexão óptica, dois métodos foram desenvolvidos. No primeiro deles as microestruturas foram excitadas através de uma lente objetiva e sua emisão foi coletada por um taper. No segundo método, tanto a excitação quanto a coleta foram realizadas por tapers de fibras ópticas. Em ambos os casos as fibras foram posicionadas através de micromanipuladores. Os resultados obtidos indicam que os tapers são ferramentas adequadas para realizar tanto a excitação quando a coleta da emissão de microestruturas, pois permitem excitação individual e coleta localizada. Produzimos microestruturas com múltiplas dopagens e pudemos concluir que a excitação localizada de diferentes partes da estrutura, bem como a correta escolha do comprimento de onda de excitação, são mecanismos que levam a alterações no espectro de emissão, o que torna estas estruturas candidatas a fontes de luz sintonizáveis que podem ser incorporadas a dispositivos on-chip. Por fim, desenvolvemos um método de produção de microestruturas conectadas a tapers. Este trabalho abre caminho para a incorporação de microestruturas poliméricas a circuitos fotônicos e demonstra que tapers de fibras ópticas são ferramentas eficientes para a realização de microconexões ópticas. / The development of integrated photonics has received a great deal of attention in the last few years. Its high functionality and signal transmission speed allow applications in several fields, from telecommunications to biology. The use of polymeric platforms in integrated photonic circuits is interesting because organic compounds can be easily incorporated to polymeric matrixes, which makes it easy to change the physical properties of the polymer according to the embed materials. Furthermore, the two-photon polymerization technique allows the production of three-dimensional polymeric microstructures with high resolution. The incorporation of these microstructures to photonic circuits paves the way for a new field of funcionalities due to the ease of modification of the polymers properties. Besides that, the structures three-dimensionality allows the performance of optical connections in three dimensions, which can improve the compacticity of the photonic devices. However, for the effective incorporation of these microstructures to photonic circuits, it is necessary to develop ways to connect them to external excitation sources, as well as analysis instruments. Optical fiber tapers, also known as microfibers or nanofibers, are good candidates for this task due to their reduced dimensions that are compatible with the size of the microstructures. In this work we developed methods for the performance of optical connections of polymeric microstructures through fiber tapers. The microstrutures were produced through the two-photon polymerization technique and organic dyes were incorporated to the polymeric matrix in order to introduce fluorescent properties. The fiber tapers were produced from conventional optical fibers through a heat-and-draw approach. To perform the optical connections, two methods were developed. In the first one, the microestructures were excited through a microscope objective and emission collection was performed by a fiber taper. In the second approach, excitation and collection were performed by fiber tapers. In both methods, the tapers were set up by micromanipulators. The obtained results indicate that tapers are a suitable tool to perform optical excitation and emission collection in microstructures, as they allow individual excitation and localized collection. Multiple doped microstructures were produced and we could imply that the localized excitation of different parts of the structures, as well as the correct choice of the excitation wavelength, are tools that lead to changes in the emission spectrum, which makes these structures candidates to tunable light sources that can be incorporated to on-chip devices. At last, we developed a method for the production of microstructures connected to fiber tapers. This work paves the way for the incorporation of polymeric microstructures to photonics circuits and demonstrates that fiber tapers are efficient tools to perform optical microconnections.

A troca de BaF2 por NaF altera as características físicas dos vidros fluorozirconados. Verificamos um aumento do índice de refração, da estabilidade frente à nnucleação e do módulo de Young com a concentração de NaF. A microdureza Vickers mostrou ser pouco afetada pelas condições de umidade, mas bastante dependente do polimento. O modelo simples, do tipo degrau, proposto para a microdureza não foi suficiente para explicar o comportamento da microdureza em função da carga. Vidros fluorozirconados dopados com Pr e Eu mostraram-se bastante estáveis, possibilitando seu emprego em fibras ópticas. Algumas composições de vidros contendo LiF mostraram uma redução do índice de refração e aumento da condutividade iônica com a concentração de LiF. A estabilidade e as propriedades de transmissão destes vidros são comparáveis às dos fluorozirconados tradicionais. Realizamos com sucesso o puxamento de fibras de vidros fluorindatos e a técnica e problemas de preparação de pré-formas são apresentados neste trabalho. / Replacing BaF2 for NaF yields physical properties modifications on fluorozirconate glasses. An increase of refraction index, thermal stability and young modulus was observed with NaF concentration. Humidity affects less Vickers microhardness than polishing conditions. A simple step model proposed for microhardness does not fit microhardness vs. load behaviors. Fluorozirconate glasses doped with Eu and Pr showed high stability allowing their use in optical fibers. Some glass compositions with LiF showed a decrease of refraction index and an increase of ionic conductivity with LiF content. Stability and transmission properties of these glasses are similar to those of traditional fluorozirconate glasses. We drew nice fibers from fluorindate glasses and the techniques and problems of perform preparation will be reported.

Orientadora: Maria del Pilar Taboada Sotomayor / Banca: Denis Ricardo Martins de Godoi / Banca: Éder Tadeu Gomes Cavalheiro / Resumo: Este trabalho propõe a síntese de MIP usando como molécula molde, ou template, o corante Verde Ácido 16 (AG16), um corante do grupo dos trifenilmetanos. A síntese foi feita pelo método em bulk; diretamente sobre a fibra óptica, usada como transdutor no desenvolvimento do sensor óptico; e também diretamente em placas de vidro, para fins de caracterização morfológica dos materiais impressos. O polímero sintetizado e o sensor construído foram caracterizados por Microscopia Eletrônica de Varredura (MEV), Espectroscopia vibracional da região no Infravermelho (IV), Reflectância Total Atenuada (RTA) e Microscopia Confocal. Os parâmetros otimizados para o desempenho do sensor foram temperatura, tempo de adsorção/pré-concentração e pH, obtendo-se os melhores resultados a 25 ºC, 60 minutos e pH 7,0; respectivamente. Sob estas condições os limites de detecção e quantificação do MIP-sensor foram 62,2 e 188 µmol L-1 respectivamente, com valores de repetibilidade e reprodutibilidade, em termos do desvio padrão relativo (RSD) abaixo de 4%. Nos experimentos realizados usando o MIP-optodo-AG16 na presença de outros quatro corantes diferentes, os valores de obtidos para a retenção/adsorção desses corantes mostraram a excelente seletividade do tip-sensor construído. Na aplicação em amostras de rio e de efluente industrial enriquecidas com AG16, os valores de recuperação obtidos foram próximos a 100% para o MIP-optodo, mostrando a eficiência do sensor em relação ao NIP-optodo. Desta forma, este ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work proposes the synthesis of a MIP using Acid Green 16 (AG16) dye as template molecule of the triphenylmethane group. The synthesis was made by bulk method directly on the optical fiber surface which is using as a transducer in the development of optical sensor and also synthesized directly on glass plates for morphological characterization of the printed materials. The synthesized polymer and the constructed sensor were characterized by Scanning Electron Microscopy (SEM), Infrared (IR), Attenuated Total Reflectance (ATR) and Confocal Microscopy. The optimized parameters were temperature, adsorption/pre-concentration time, pH, obtaining the best results at 25 ºC, 60 minutes and pH 7,0 respectively. Under these conditions for the MIP-sensor the limits of detection and quantification were 62.2 and 188 μmol L-1 respectively, with repeatability and reproducibility values in terms of relative standard deviation (RSD) below 4%. The experiments were performed using MIP-optode-AG16 in presence of four other different dyes and the values obtained for the retention/adsorption of those dyes showed the excellent selectivity of the constructed tip-sensor. For application the river samples and industrial effluent were enriched with AG16 and recovery values were obtained close to 100% for the MIP-optodo that showing the efficiency of the sensor in relation to the NIP-optodo. Thus this master's work shows the development of an exceptional optical sensor for the literature with excelle... (Complete abstract click electronic access below) / Mestre

Currently, optical communications plays an important role in the transmission aspect of backbone fiber networks. However, there still remain two challenges in this field: one is the bottleneck between high-capacity local area networks (LANs) and the backbone network, where the answer is the broadband optical fiber access networks; the other is the bottleneck of low-speed electrical signal processing in high capacity optical networks, where one possible solution is all-optical nonlinear signal processing. This thesis will cover both of the two topics. In the first topic, the emphasis will be put on the novel optical access network infrastructure design to improve the access network reliability and functionality as well as the reduction of system complexity. In the second topic, the focus is how to utilize the newly-emerging photonic devices or newly-designed configurations to improve the performance of current optical signal processing subsystems for applications in lightwave transmission systems. / In summary, this thesis introduces a series of novel optical access network architecture designs and transmission system technologies for optical fiber communications and discusses their feasibilities in practice from the research perspective. We hope that these proposed technologies can contribute to the further developments in this field. / In the area of broadband optical fiber access networks, two aspects are considered: survivability and monitoring function. For the first part, several new network protection schemes among various access network topologies (i.e. tree and ring) are proposed and experimentally demonstrated, which could reduce the access network cost and simplifying the operation of the access network. For the second part, an interesting in-service fault surveillance scheme in the current TDM-PON is proposed via analyzing the composite radio-frequency (RF) spectrum of the common supervisory channel at the central office (CO). Experiment proves its effectiveness with negligible influence on the signal channels. In addition, a system demonstration of the WDM-based optical broadband access network with automatic optical protection function is presented, showing the potential of WDM technologies in the broadband optical access networks. / In the area of nonlinear optical signal processing, the technology innovation is in two areas: new architecture design and the new photonic devices. For the issue of architecture design, the focus is on the Nonlinear Optical Loop Mirror (NOLM) structure. A new polarization-independent OTDM demultiplexing scheme is proposed and demonstrated by incorporating a polarization-diversity loop into a conventional NOLM, which offers stable operation using the conventional components without sacrificing the operation speed or structural simplicity. In another study the design of a novel OFSK transmitter based on phase-modulator-embedded NOLM is conceived and implemented, which features data-rate transparent, continuous tuning of the wavelength spacing and stable operation. For the aspect of new photonic devices, this thesis focuses on the applications of photonic crystal fibers (PCF). In one work, a relatively short-length of dispersion-flattened high-nonlinearity PCF (gamma=11.2 (W-km)-1, D<-1 ps/nm/km 1500-1600 nm, S<1 x 10-3 ps/km/nm2) is integrated into a dispersion-imbalanced loop mirror (DILM) to form a nonlinear intensity discriminator and its application in the nonlinear suppression of the incoherent interferometric crosstalk has been successfully demonstrated. The special characteristics of the PCF ensure a broadband signal quality improvement and make the DILM more compact and stable. In the other work, the small birefringence of this PCF helps to simply achieve the polarization-insensitive wide-band wavelength converter based on four-wave-mixing in PCF. / Wang Zhaoxin. / "September 2006." / Advisers: Chinlon Lin; Chun-Kit Chan. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1846. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 93-101). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

La surveillance des structures de génie civil, afin d'en estimer l'état de santé, est un enjeu majeur pour les maîtres d'ouvrages. Les systèmes de mesures réparties par fibre optique, composés d'un interrogateur connecté à une fibre optique intégrée dans un câble, permettent de mesurer le profil de déformation avec un pas de mesure centimétrique et une portée kilométrique. Ils sont donc adaptés aux structures présentant de grands linéaires ou de grandes surfaces. Mais, avant tout déploiement industriel, il est nécessaire d'en évaluer leurs performances. Du fait de la déformation par cisaillement du revêtement du câble, le profil de déformation mesuré le long de la fibre optique n'est pas strictement identique à celui du matériau environnant. Une méthode, basée sur la mise en œuvre d'essais et de simulations numériques, a été développée afin de caractériser les mécanismes de transfert d'effort du milieu hôte à la fibre optique à travers le revêtement du câble. Cette méthode a été appliquée pour déterminer la réponse mécanique d'un câble particulier noyé dans le béton. Les performances métrologiques d'un système de mesure donné ont été évaluées sur la base d'une analyse d'essais « du laboratoire au terrain ». Cette étude a permis de quantifier les différentes composantes d'incertitude et d'estimer les performances du système de mesure complet. Enfin, le câble, noyé dans le béton, ne peut être remplacé. La connaissance de l'impact du vieillissement sur la réponse mécanique du câble est donc primordiale. Une étude spécifique est menée dont le but est d'estimer la durabilité du câble face aux sollicitations chimique, thermique et mécanique correspondant à une application donnée / Structural Health Monitoring is a key factor in life-cycle management of civil structures. Truly distributed fiber optic sensors, composed by an optoelectronic device paired with an optical fiber in a cable, provide strain profiles over several kilometers with a centimeter resolution. They are thus able to provide relevant information on large structures. However, a preliminary performance assessment is required prior to any industrial application. Due to shear deformation of the cable's protective coating, strain measurements provided by the measuring system may differ from actual strains in the embedding medium. A methodology, based on mechanical tests and modelling, was thus developed to determine the relationship between measured/actual strains. It was applied to determine the mechanical response of a specific cable embedded in concrete. Performance assessment method was applied to a specific measuring system. Tests were carried out under laboratory conditions on the fiber optic cable, out of the concrete medium in a first stage, and then embedded in concrete structures. It enabled to evaluate its components and standard uncertainties. The cable could not be replaced after being embedded in concrete. It is necessary to evaluate the ageing effects on its mechanical properties to use it for a long term period. A specific study was carried out to determine the cable durability under chemical, thermal and mechanical solicitations

O desenvolvimento da fotônica integrada vem recebendo muita atenção nos últimos anos. Sua alta funcionalidade e velocidade de transmissão de sinais possibilitam a aplicação em diversas áreas, que vão desde comunicações até biologia. O uso de polímeros em circuitos fotônicos integrados tem se mostrado interessante, pois compostos orgânicos podem ser facilmente incorporados a matrizes poliméricas. Isso faz com que as propriedades físicas do polímero possam ser modificadas de acordo com os materiais incorporados. Além disso, a técnica da fotopolimerização por absorção de dois fótons torna possível a produção de microestruturas poliméricas tridimensionais com alta resolução. A incorporação dessas microestruturas a circuitos fotônicos pode trazer um novo ramo de funcionalidades devido à facilidade de modificação das propriedades dos polímeros. Além disso, a tridimensionalidade das estruturas permite a realização de conexões ópticas em três dimensões, o que colabora para o aumento da compacticidade dos dispositivos fotônicos. No entanto, para que estas microestruturas possam ser efetivamente incorporadas aos circuitos fotônicos é necessário desenvolver formas de conectá-las a fontes externas de excitação, bem como a instrumentos de análise de sinais. Os tapers de fibras ópticas, também conhecidos como microfibras ou nanofibras, são bons candidatos para realizar essa tarefa devido a suas dimensões reduzidas, as quais são compatíveis com o tamanho das microestruturas. Neste trabalho desenvolvemos métodos para realizar a conexão óptica entre microestruturas poliméricas e tapers de fibras ópticas. As microestruturas foram produzidas através da técnica de fotopolimerização por absorção de dois fótons e corantes orgânicos foram incorporados à matriz polimérica para conferir propriedades fluorescentes às estruturas. Os tapers foram produzidos a partir de fibras ópticas convencionais por uma técnica de aquecimento e estiramento. Para realizar a conexão óptica, dois métodos foram desenvolvidos. No primeiro deles as microestruturas foram excitadas através de uma lente objetiva e sua emisão foi coletada por um taper. No segundo método, tanto a excitação quanto a coleta foram realizadas por tapers de fibras ópticas. Em ambos os casos as fibras foram posicionadas através de micromanipuladores. Os resultados obtidos indicam que os tapers são ferramentas adequadas para realizar tanto a excitação quando a coleta da emissão de microestruturas, pois permitem excitação individual e coleta localizada. Produzimos microestruturas com múltiplas dopagens e pudemos concluir que a excitação localizada de diferentes partes da estrutura, bem como a correta escolha do comprimento de onda de excitação, são mecanismos que levam a alterações no espectro de emissão, o que torna estas estruturas candidatas a fontes de luz sintonizáveis que podem ser incorporadas a dispositivos on-chip. Por fim, desenvolvemos um método de produção de microestruturas conectadas a tapers. Este trabalho abre caminho para a incorporação de microestruturas poliméricas a circuitos fotônicos e demonstra que tapers de fibras ópticas são ferramentas eficientes para a realização de microconexões ópticas. / The development of integrated photonics has received a great deal of attention in the last few years. Its high functionality and signal transmission speed allow applications in several fields, from telecommunications to biology. The use of polymeric platforms in integrated photonic circuits is interesting because organic compounds can be easily incorporated to polymeric matrixes, which makes it easy to change the physical properties of the polymer according to the embed materials. Furthermore, the two-photon polymerization technique allows the production of three-dimensional polymeric microstructures with high resolution. The incorporation of these microstructures to photonic circuits paves the way for a new field of funcionalities due to the ease of modification of the polymers properties. Besides that, the structures three-dimensionality allows the performance of optical connections in three dimensions, which can improve the compacticity of the photonic devices. However, for the effective incorporation of these microstructures to photonic circuits, it is necessary to develop ways to connect them to external excitation sources, as well as analysis instruments. Optical fiber tapers, also known as microfibers or nanofibers, are good candidates for this task due to their reduced dimensions that are compatible with the size of the microstructures. In this work we developed methods for the performance of optical connections of polymeric microstructures through fiber tapers. The microstrutures were produced through the two-photon polymerization technique and organic dyes were incorporated to the polymeric matrix in order to introduce fluorescent properties. The fiber tapers were produced from conventional optical fibers through a heat-and-draw approach. To perform the optical connections, two methods were developed. In the first one, the microestructures were excited through a microscope objective and emission collection was performed by a fiber taper. In the second approach, excitation and collection were performed by fiber tapers. In both methods, the tapers were set up by micromanipulators. The obtained results indicate that tapers are a suitable tool to perform optical excitation and emission collection in microstructures, as they allow individual excitation and localized collection. Multiple doped microstructures were produced and we could imply that the localized excitation of different parts of the structures, as well as the correct choice of the excitation wavelength, are tools that lead to changes in the emission spectrum, which makes these structures candidates to tunable light sources that can be incorporated to on-chip devices. At last, we developed a method for the production of microstructures connected to fiber tapers. This work paves the way for the incorporation of polymeric microstructures to photonics circuits and demonstrates that fiber tapers are efficient tools to perform optical microconnections.

High performance communications, sensing and computing systems are growing exponentially as modern life continues to rely more and more on technology. One of the factors that are currently limiting computing and transmission speeds are copper wire interconnects between devices. Optical fiber interconnects would greatly increase the speed of today’s electronic devices. In this study it has been demonstrated that by using a new Direct Print Additive Manufacturing (DPAM) process of Fused Deposition Modeling (FDM) of plastic and micro-dispensing of pastes and inks, we can 3D print single and multi-mode optical fibers in a controlled manner such that compact, 3-dimensional optical interconnects can be printed along non-lineal paths. We are FDM printing the core materials from a plastic PMMA material. We are dispensing a urethane optical adhesive as the core material. These materials are available in many different refractive indices. During numerical simulations of these fibers, we were able to show through manipulation of the refractive indices of the core and cladding that we can also improve the bend performance of our fibers. As a result, they can perform better as an interconnect in tight routings between components as long as the interconnect fiber distances remain less than 1 meter. Fibers have been fabricated with diameters between 77 and 17 µm across an air gap with a surface roughness of less than 450 nm and cladded and tested with transmission rates of about 46%. 12 µm fibers have successfully been fabricated on a cladded surface as a proof of concept to test the small diameter and 3D shaping capability of this process.

The mechanical grinding processes is the most popular way to fabricate the end face of optical fibers, although there are some other methods like chemical etching and leaser machining. In cases of fabricate the wedge type and wedge-cone type optical fiber end faces, the mechanical grinding is the typical way. Professor Y. C. Tsai¡¦s research group has successfully fabricated the optical fiber with elliptical-cone-type end-face in a single grinding process by adopting a mechanism with eccentric mass on the commercial optical fiber grinding machine. In this study, a torque motor is equipped on the commercial optical fiber grinding machine for controlling the normal pressure between the optical fiber and the grinding film during the grinding process. While the optical fiber rotating, the normal pressure, as well as the material removed rate and the final shape of the optical fiber, can be controlled in different periodical mode shapes by applying different voltages with different periodical mode shapes. The merit of this system is its capability of fabricating fiber with elliptical-cone-shape and polygon-cone-shape (polyhedron-tip) end faces in a single grinding process that will increase the efficiency and the accuracy of grinding. It is believed the grinding machine system developed in this study can be successfully applied for fabricating the optical fiber lenses as well as different types of micro probes for other applications.