Endlessly single-mode fibers, which enable single mode guidance over a wide spectral range, are indispensable in the field of fiber technology. A two-dimensional photonic crystal with a silica central core and a micrometer-spaced hexagonal array of air holes is an established method to achieve endless single-mode guidance. There are two possible ways to determine the dispersion: measurement and calculation. We calculate the group velocity dispersion GVD based on the measurement of the fiber structure parameters, the hole diameter and the pitch of a presumed homogeneous hexagonal array and compare the calculation with two methods to measure the wavelength-dependent time delay. We measure the time delay on a three hundred meter test fiber with a homemade supercontinuum light source, a set of bandpass filters and a fast detector and compare the results with a white light interferometric setup. To measure the dispersion of optical fibers with high accuracy, a time-frequency-domain setup based on a Mach-Zehnder interferometer is used. The experimental setup allows the determination of the wavelength dependent differential group delay of light travelling through a thirty centimeter piece of test fiber in the wavelength range from VIS to NIR. The determination of the GVD using different methods enables the evaluation of the individual methods for characterizing the endlessly single-mode fiber.

The optical properties of the guided modes in the core of photonic crystal fibers (PCFs) can be easily manipulated by changing the air-hole structure in the cladding. Special properties can be achieved in this case such as endless singlemode operation. Endlessly single-mode fibers, which enable single-mode guidance over a wide spectral range, are indispensable in the field of fiber technology. A two-dimensional photonic crystal with a silica central core and a micrometer-spaced hexagonal array of air holes is an established method to achieve endless single-mode properties. In addition to the guidance of light in the core, different cladding modes occur. The coupling between the core and the cladding modes can affect the endlessly single-mode guides. There are two possible ways to determine the dispersion: measurement and calculation. We calculate the group velocity dispersion (GVD) of different cladding modes based on the measurement of the fiber structure parameters, the hole diameter and the pitch of a presumed homogeneous hexagonal array. Based on the scanning electron image, a calculation was made of the optical guiding properties of the microstructured cladding. We compare the calculation with a method to measure the wavelength-dependent time delay. We measure the time delay of defined cladding modes with a homemade supercontinuum light source in a white light interferometric setup. To measure the dispersion of cladding modes of optical fibers with high accuracy, a time-domain white-light interferometer based on a Mach-Zehnder interferometer is used. The experimental setup allows the determination of the wavelengthdependent differential group delay of light travelling through a thirty centimeter piece of test fiber in the wavelength range from VIS to NIR. The determination of the GVD using different methods enables the evaluation of the individual methods for characterizing the cladding modes of an endlessly single-mode fiber.

This paper describes simulation, technology- and process development for the manufacturing of single mode polymeric waveguides by photolithography. Simulations for single mode operation in O- and C-band are carried out. Waveguides are directly patterned with UV-photolithography using Ormocere®-material. Fiber to waveguide coupling and near field are characterized.

Orientadores: Cristiano Monteiro de Barros Cordeiro, Marcos Antonio Ruggieri Franco / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-22T12:56:38Z (GMT). No. of bitstreams: 1 PinillaPachon_EdwinGerman_M.pdf: 12541930 bytes, checksum: 74a0367c344ded9c8891d11280568b6b (MD5) Previous issue date: 2013 / Resumo: Nesta dissertação se estudou por simulação numérica o efeito de interferência multimodal (MMI, do inglês "multimode interference") em guias de onda, com atenção especial a fibras ópticas, e a resposta óptica do dispositivo MMI a parâmetros externos como temperatura, curvatura e índice de refração. Dispositivos baseados em MMI são formados, em geral, por três guias de onda concatenados sendo as extremidades compostas de guias monomodo e a parte central composta de um guia que permite a propagação de muitos modos, tipicamente, mais do que três. Nesta situação, na seção multimodo, são formadas reimagens que aproximadamente replicam fase e amplitude do campo óptico de entrada. A observação do espectro de transmissão correspondente à primeira reimagem, em dispositivos MMI, permite desenvolver sensores de índice de refração, temperatura e curvatura. A sensibilidade dos sensores foi avaliada frente às variações do mensurando, ou seja, variações no índice de refração, temperatura e curvatura da estrutura MMI em fibra óptica. / Abstract: In this work the effect of multimodal interference (MMI) in waveguides was studied by numerical simulation. Special attention was given to optical fibers and its the optical response when external parameters such as temperature, curvature or refractive índex were varied. MMI devices are usually formed by connecting three waveguides being the input and output ones single mode waveguides while the middle one is a waveguide that allows the propagation of many optical modes, typically more than three. In this situation re-images that replicate both the phase and the amplitude of the input optical field are formed periodically within the multimode section. The analysis of the transmission spectrum of the first re-image in MMI devices were realized in order to get information about the fiber environment, in particular the surrounding refractive índex, radius of curvature and temperature. The sensors sensitivity was evaluated. / Mestrado / Física / Mestre em Física

L'objectif de cette thèse vise à l'étude d'un laser à cavité étendue et/ou filtre optique, dont le miroir externe est un réseau de Bragg à pas variable linéairement. En ce qui concerne le milieu à gain dans le résonateur, l’amplificateur optique à semiconducteur (SOA, Semiconductor Optical Amplifier) peut offrir toutes les caractéristiques et avantages classiques et typiques tels que large bande passante spectrale de 50 nm, faible consommation, haute rapidité de commutation électro-optique etc.... Par conséquent, ce type de laser et/ou filtre optique offre de nombreuses applications intéressantes dans le domaine des télécommunications optiques.Dans cette recherche, les premiers travaux sont la conception de la cavité continuum passive à l'aide d’un réseau de Bragg à pas variable. A l’intérieur de cette cavité continuum, formée entre un miroir et un réseau de Bragg chirpé, toutes les longueurs d'onde de Bragg oscillent simultanément ; la phase après un aller-retour de chaque longueur d'onde doit rester constante. La largeur de bande passante du spectre de transmission peut être ajustée dans la bande C (entre 1525 nm et 1565 nm) pour répondre aux besoins des systèmes de multiplexage en longueur d'onde (WDM, Wavelength-Division Multiplexing). On appliquera dans un premier temps ce concept de cavité continuum à la conception et la réalisation d’un filtre optique à bande passante variable. Puis dans un deuxième temps on rajoute un amplificateur optique à semi-conducteur (SOA) dans cette cavité pour réaliser un laser dit continuum. On s’attend à une émission sur un large spectre défini par la bande de réflexion du réseau chirpé. Le contrôle et la compréhension des phénomènes liés à cette émission lumineuse feront l’objet de cette étude. La cavité laser dite continuum sera étudiée en régime d’injection optique. L’idée est d’utiliser cette source comme amplificateur résonant fonctionnant en régime d’injection locking. La contribution dans cette thèse couvre à la fois la modélisation numérique, et les manipulations expérimentales. La conception du filtre ainsi que des mesures expérimentales de validation ont été complètement réalisés sur une structure hybride constituée d’une cavité à fibre optique incluant les réseaux de Bragg. Un bon accord entre théorie et expérience a été obtenu. Par contre, les calculs ont montré qu’un filtre optique intégré sur semi-conducteur utilisant ce concept de cavité n’avait pas d’intérêt. Les propriétés spectrales du filtre réalisé montrent en effet qu’on ne pourra obtenir qu’un faible taux de réjection et une qualité médiocre de forme de filtre en version intégrée. La réalisation expérimentale d’une cavité laser continuum a pu être démontrée et les propriétés spectrales enregistrées. En particulier une émission laser avec une largeur de spectre de 10 nm a été observée. Même si il reste un grand travail de caractérisation et de modélisation pour comprendre totalement les mécanismes qui gouvernent le fonctionnement d’une telle structure, c’est un résultat totalement nouveau que l’on a obtenu ici. Cette structure a par ailleurs été testée en régime d’injection optique. Un fonctionnement d’injection locking est obtenu qui permet à cette structure de jouer le role d’amplificateur à faible bruit. / The aim of this thesis is focused on the study of an extended cavity laser or/and optical filter, whose external mirror is the linearly chirped Bragg grating. As for the gain medium in the resonant, SOA (Semiconductor Optical Amplifier) can act as optical gain device. It can offer all of the classic and typical characteristics and advantages like large spectral passband of 50 nm, low power consumption, high-speed electro-optical commutation and so on. Therefore, this type of laser or/and optical filter have many interesting applications in the field of optical telecommunications.In this research, the first works are the design of passive continuum resonant cavity using linearly chirped Bragg grating. Inside this so-called continuum cavity, formed between mirror and chirped grating, all of the Bragg wavelengths oscillate at the same time, so the round-trip phase of each oscillated wavelength should keep constant. Then there is a passband spectrum at the transmission side. The bandwidth of transmission could be varied in C band (from 1525 nm to 1565 nm) to satisfy the needs of wavelength-division multiplexing (WDM) systems. This project is separated by two cases, one is about the external cavity applying chirped fiber Bragg grating as an external mirror, and the other is about the integrated cavity on InP chip, where the Bragg grating is already lithographed. Anyway, the first works of the thesis consist of numerical modeling, computational simulations and experimental manipulations.During the second works, the first step we add SOA as gain medium between two chirped fiber Bragg gratings for the purpose of generating laser. There are reflectors and active part in the passive cavity, so there is lasing far and away. It emits the typical F-P multimode light at the intersection of SOA gain band and reflection band of chirped grating. Then the second step is that a seed laser, whose frequency is nearby one of the longitudinal modes, is injected into the cavity in order to lock this mode. So there is only one emitted laser mode because of injection locking. This lasing resonant cavity could also be formed between mirror and linearly chirped Bragg grating.

Um der Mikrowellenerwärmung als Single- oder Hybridanwendung im industriellen Ofenbau ein weiteres Anwendungsspektrum zu eröffnen, wird dem Anlagenkonstrukteur im Rahmen dieser Arbeit eine Aufstellung von Entwicklungsprioritäten und Konstruktionshinweisen übergeben. Für eine energieeffiziente Ausnutzung des technologischen Potenzials wird hierbei nicht - wie in der Vergangenheit - die Feldstärkenverteilung, sondern das Reflexionsverhalten in den Vordergrund gestellt. Durch die Entwicklung und den Aufbau eines Messplatzes zur Bestimmung temperaturspezifischer Dielektrizitätsparameter konnte die Realitätsnähe der Simulation für die anwendungsorientierte Applikatorentwicklung gesteigert werden. Die Anwendbarkeit der Auslegungskriterien wird im Rahmen der Projektierung und des Aufbaus einer Beispielanlage zur Entbinderung von keramischen Grünkörpern und bei der Entwicklung zahlreicher mikrowellenspezifischer Anlagenbauteile verifiziert.

The master theses deals with a detailed analysis of optical fiber sensors. Specifically, there are discussed optical fibers, various types of sensors and realization optical fiber senzor and senzor system that has been optimized and processed data in real time. In master theses also describes the LabView programming enviroment and uses components, including the entire sensor systém of a sensors system that sends measured data

Um der Mikrowellenerwärmung als Single- oder Hybridanwendung im industriellen Ofenbau ein weiteres Anwendungsspektrum zu eröffnen, wird dem Anlagenkonstrukteur im Rahmen dieser Arbeit eine Aufstellung von Entwicklungsprioritäten und Konstruktionshinweisen übergeben. Für eine energieeffiziente Ausnutzung des technologischen Potenzials wird hierbei nicht - wie in der Vergangenheit - die Feldstärkenverteilung, sondern das Reflexionsverhalten in den Vordergrund gestellt. Durch die Entwicklung und den Aufbau eines Messplatzes zur Bestimmung temperaturspezifischer Dielektrizitätsparameter konnte die Realitätsnähe der Simulation für die anwendungsorientierte Applikatorentwicklung gesteigert werden. Die Anwendbarkeit der Auslegungskriterien wird im Rahmen der Projektierung und des Aufbaus einer Beispielanlage zur Entbinderung von keramischen Grünkörpern und bei der Entwicklung zahlreicher mikrowellenspezifischer Anlagenbauteile verifiziert.

This paper describes technology and process development for a hybrid lithography approach pairing UV-lithography for planar single mode waveguides with 2-photon-polymerization direct-laser-writing for out-of-plane coupling mirrors. Improvements to multi-layer direct patterning of OrmoCore/-Clad material system using UV-lithography are presented. Near square core cross sections are achieved. Minimum alignment accuracy at ≈ 3 μm is observed. Cut-back measurement on single mode waveguides shows attenuation of 0.64 dB cm −1 and 1.5 dB cm −1 at 1310 nm and 1550 nm respectively. Up to 2.5-times increase of shear-strength after thermal exposure up to 300 ◦ C is found using shear tests and compared for various surface treatments. Mechanical compatibility to reflow soldering is derived. An extensive study on the pattering of ORMOCER® using 2-photon-polymerization is performed. Flat 45 ◦ -micro mirrors with sub-10 μm dimensions are 3D-printed both in OrmoCore and OrmoComp. Outlook to further research on hybrid lithography integration approach is given.

This paper describes design and advances in process development for UV-lithography of planar single mode waveguides with openings for out-of-plane coupling µ-mirrors. Improvements to multi-layer direct patterning of OrmoCore/-Clad material system using UV-lithography are presented. Near square core cross sections are achieved. However, non uniformity across 4” wafer is shown due to varying proximity and UV-intensity. Openings in full stack with steep sidewalls without residual layer are patterned. Reduction in stack thickness for very small exposure doses due to inhibition even under inert atmosphere is shown. 45° -µ-mirrors are integrated in these openings to manufacture a U-link via a single mode waveguide and two adjacent micro-mirrors. Optical characterization of U-link demonstrates the feasibility of hybrid lithography approach. However, non-uniformity of core cross-section leads to cross coupling of planar waveguides. Outlook to further research on UV-lithography of multi-layer waveguide stack and alignment with µ-mirror printing is given.