Eidgenössische Techn. Hochsch, Diss--Zürich, 2000.

The objective of this thesis was to develop applications of monolithic fiber devices and actively controlled fibers. A special twin-core fiber known as a ‘Gemini’ fiber was used to construct equal arm-length fiber interferometers, impervious to temperature and mechanical perturbations. A broadband add/drop multiplexer was constructed by inscribing fiber Bragg gratings in the arms of a Gemini Mach-Zehnder interferometer. A broadband interferometric nanosecond switch was constructed from a micro-structured Gemini fiber with incorporated metal electrodes. Additionally, a Michelson fiber interferometer was built from an asymmetric twin-core fiber and used as a high-temperature sensor. While the device could be readily used to measure temperatures below 300 °C, an annealing process was required to extend the range up to 700 °C. The work included development, construction and evaluation of the components along with numerical simulations to estimate their behaviors and to understand the underlying processes. The thesis also explored the use of electrically controlled fibers for filtering in the microwave domain. An ultra-narrow phase-shifted fiber Bragg grating inscribed in a fiber with internal electrodes was used as a scanning filter to measure modulation frequencies applied to an optical carrier. A similar grating was used inside a dual-wavelength fiber laser cavity, to generated tunable microwave beat frequencies. The studied monolithic fiber interferometers and actively controlled fibers provide excellent building blocks in such varied field as in microwave photonics, telecommunications, sensors, and high-speed switching, and will allow for further applications in the future. / Syftet med denna avhandling var att utveckla tillämpningar av monolitiska fiber komponenter samt aktivt kontrollerbara fiber. En speciell tvillingkärnefiber, även kallad ’Geminifiber’ användes för att konstruera fiber interferometrar med identisk armlängd som ej påverkas av termiska och mekaniska variationer. En bredbanding utbytarmultiplexor konstruerades genom att skriva in fiber Bragg gitter inuti grenarna på en Gemini Mach-Zehnder interferometer. Geminifibrer med interna metallelektroder användes för att konstruera en bredbandig nanosekundsnabb interferometrisk fiberomkopplare. Därtill användes en tvillingkärnefiber som en hög-temperatursensor. Även om komponenten direkt kan användas upp till 300 °C, måste den värmebehandlas för att kunna användas upp till 700 °C. Arbetet har innefattat utveckling, konstruktion och utvärdering av komponenterna parallellt med numeriska simuleringar för att analysera deras beteenden samt få insikt om de underliggande fysikaliska processerna. Avhandlingen behandlar även tillämpningar av en elektriskt styrbar fiber för att filtrera radiofrekvenser. Ett ultrasmalt fasskiftat fiber Bragg gitter skrevs in i en fiber med interna elektroder och användes som ett svepande filter för att mäta modulationsfrekvensen på en optisk bärfrekvens. Ett liknande gitter användes inuti en laserkavitet för att generera två olika våglängder samtidigt. Dessa två våglängder användes sedan för att generera en svävningsfrekvens i mikrovågsbandet. De undersökta monolitiska fiberinterferometrarna och de aktivt styrbara fibrerna erbjuder en utmärkt byggsten inom så pass skiljda områden som Mikrovågsfotonik, Telekommunikation, Sensorer samt Höghastighets-omkopplare och bör kunna användas inom många olika tillämpningar i framtiden. / <p>QC 20130226</p>

In response to the development of a next-generation networking (NGN) generalized multi-protocol label switching (GMPLS) technology is required for automatically switched optical network (ASON). Reconfigurable optical add-drop multiplexer (ROADM) is an indispensable device for the ASON, and the dense wavelength division multiplexed (DWDM) signals can be transmitted through the network under the management of the network administrator to configure dynamic customer needs and the desired quality of service (QoS). The ROADM can also increase the efficiency of utilizing the existing capacity of the optical fiber lines and can reduce or waive to set up additional optical fiber lines. This thesis studies a novel ROADM based on the arrayed waveguide grating (AWG) and the fiber Bragg grating (FBG) to overcome that the current ROADM cannot process that the input signal channels is greater than the wavelengths channels of AWG. Many types of ROADMs have been proposed and realized through different optical devices. Among these, hybrid optical circulator and FBG based ROADM is more attractive because of its low crosstalk and polarization insensitivity. However, it still suffers from many component counts and high insertion losses due to the use of many circulators and a multiplexer-demultiplexer pair. In this master thesis, we focus on demonstrating a novel ROADM and evaluating its crosstalk performance. It is found that the proposed ROADM has the advantage on extending the number of wavelength signal to make the system configurable and flexible.

Le trafic dans les réseaux optiques est en constante augmentation depuis de nombreuses années. CISCO affirme qu'il devrait augmenter d'un facteur 13 en 2020. Ceci induit une augmentation de la consommation énergétique et de l'évolution de la taille des réseaux entrainant un accroissement de la complexité des réseaux. Dans ce contexte, pour répondre à l'augmentation du débit dans les réseaux et procure un réseau de télécommunications fiable, il faut prévoir une planification et une ingénierie de réseaux adaptées. Dans ce but, nous étudions dans cette thèse le design d'un nœud de commutation optique ROADM. nous considérons différentes architectures de nœud, composants et sous-systèmes utilisés dans les configurations de nœud RODM "Broadcast and Select" et "Route and Select". Diverses configurations de modules d'insertion/extraction sont analysées ("Colored/colorless, directional/directionless et contentional/contentionless"). Pour ce faire, nous avons développé un simulateur de nœud ROADM dans une plateforme de trafic dynamique et nous avons proposé une stratégie de gestion offline de la contention à l'intérieur du nœud. Nous avons obtenu une réduction du rapport de blocage intra noeud de l'ordre de 1.5. Ensuite, nous nous sommes focalisés sur la planification des futures générations de réseaux optiques métro cœur. Dans ce but, nous avons étudié la possibilité d'une transmission non cohérente à 100 Gb/s en utilisant le format de modulation PDM-DQPSK. Ensuite, nous avons considéré l'implémentation de la PDM-CS-DQPSK. La qualité de transmission de ces deux systèmes a finalement été évaluée / Traffic demand is exponentially increasing in recent years. Cisco forecast claims that by 2020, transport traffic will be 13 times of today's traffic transmission. This incremental traffic demand makes concerns about energy consumption and network scalability as well as increasing the network complexity. In this respect, to adresse the future traffic demand requirement and provide a reliable telecommunication network, precise network planning and engineering are needed. To this aim, we adress the problem of ROADM node design by presenting different architectures, components and subsystems to investigate the Broadcast and Select and Route and Select ROADM node architectures. Colored/colorless, directional/directionless and contentional/contentionless add/drop module configurations are studied. Futhermore, the problem of Intra Node Blocking is investigated by developing a node simulator in a dynamic network traffic platform. In this respect, we propose an offline contention management strategy for an ROADMnode in order to efficiently decrease the Intra Node blocking ration by more than 1.5 order of magnitude. Finally, we focus on network planning by investigating short and medium term network upgrades for metro-core optical network. To this goal, we investigate the possibility of non coherent signal transmission in metro-core segment of hierarchical layered optical network. Quality of transmission for 100 Gbit/s PDM-DQPSK-modulation format is investigated. Then, we propose the implementation of PDM-CS-DQPSK modulation format to transmit 100 Gbit/s signals in ROADM based optical transmission systems