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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Microeletromechanical Systems for Tunable Ring Resonators on a Silicon Platform

Nguyen, Chris Phong Van January 2021 (has links)
Advancements in photonic integrated circuits, so-called PICs, have progressed fast in the last decades. More complex PICs are getting developed, which are promising in possibly offering advantages like low power consumption and high-performance computing. Re-programmable photonic FPGAs are one of these candidates. To make these PICs viable, fundamental building blocks based on photonics need to be developed. Some of those fundamental building blocks are tunable silicon ring resonators, which can be used to filter signals in the transmission of light through photonic circuits. Fabrication of PICs is developing and those components are getting smaller, which leads to a strong sensitivity of their behavior to nanometer-scale variations. That has created a need for active tuning of those devices to recuperate those variances. One promising way to tune silicon ring resonator devices is to integrate microelectromechanical systems (MEMS) into the tuning section of the devices, because of their local and low power actuation. They are prospective to eliminate drawbacks from usual actuation methods like thermal actuation, which comes with high power consumption and cross talk while heating the functional sections of the ring. In this thesis, we have measured and analyzed MEMS-tunable silicon ring resonators, featuring two different designs, being an all-pass ring resonator and an add-drop ring resonator. The MEMS in the design are used to change the gap between the waveguides in their directional coupler and phase shifter section to control the position and extinction ratios of the ring resonance dips, which has been successfully demonstrated for the all-pass ring resonator. For the add-drop ring resonators, we have obtained performance parameters of their resonances with an average Q-factor of 3000 over the measured wavelength ranged from 1460nm to 1580nm and the characteristic behavior of their transmission has been shown without actuation. Further investigation with MEMS actuation of add-drop ring resonators and passive measurements on all-pass ring resonators can be done for a better understanding of their behavior and functionality. This can be achieved by characterizing all-pass ring resonators in terms of obtained performance parameters and by active measurements on add-drop ring resonators, as we expect that their MEMS could enable similar functionalities as all-pass ring resonators. Our first characterization results confirm the potential of MEMS for ring resonator tuning and could enable future circuits based on ring resonators with low power consumption. / Framsteg inom fotoniska integrerade kretsar, så kallade PIC, har utvecklats snabbt under de senaste decennierna. Mer komplexa PIC utvecklas, vilket lovar att möjligen erbjuda fördelar som låg strömförbrukning och högpresterande datorer. Omprogrammerbara fotoniska FPGA är en av dessa kandidater. För att göra dessa PICs livskraftiga måste grundläggande byggstenar baserade på fotonik utvecklas. Några av dessa grundläggande byggstenar är avstämningsbara kiselringresonatorer, som kan användas för att filtrera signaler vid överföring av ljus genom fotoniska kretsar. Tillverkning av PIC utvecklas och dessa komponenter blir mindre, vilket leder till en stark känslighet för variationer, även på nanometer skala. Det har skapat ett behov av aktiv inställning av dessa enheter för att återhämta dessa avvikelser. Ett lovande sätt att ställa in kiselringresonatoranordningar är att integrera mikroelektromekaniska system (MEMS) i enhetens stämningsdel på grund av deras lokala och lågeffektaktivering. De kan eliminera nackdelar med vanliga manövreringsmetoder som termisk aktivering, som kommer med hög strömförbrukning och termisk överhöring. I denna avhandling har vi mätt och analyserat MEMS-avstämbara kiselringresonatorer, med två olika designer, som är en all-pass ringres-onator och en add-drop ringresonator. MEMS i konstruktionen används för att ändra gapet mellan vågledarna i deras kopplare och fasskiftarsektion för att styra positionen och djupet på ringresonaserna, vilket har visats framgångsrikt för allpassningsresonatorn. För add-dropringresonatorer har vi erhållit prestandaparametrar för deras resonanser med en genomsnittlig Q-faktor på 3000 över den uppmätta våglängden som varierar från 1460 nm till 1580 nm och det karakteristiska beteendet för deras överföring har visats utan aktivering. Ytterligare undersökning med MEMS-aktivering av add-drop-ringresonatorer och passiva mätningar på all-pass-ringresonatorer kan göras för en bättre förståelse av deras beteende och funktionalitet. Detta kan uppnås genom att karakterisera allpassningsresonatorer i termer av erhållna prestandaparametrar och genom aktiva mätningar på add-drop-ringresonatorer, eftersom vi förväntar oss att deras MEMS kan möjliggöra liknande funktioner som all-pass-ringresonatorer. Våra första karakteriseringsresultat bekräftar MEMS potential för ringresonatorinställning och kan möjliggöra framtida kretsar baserade på ringresonatorer med låg strömförbrukning.
52

Design and Analysis of High-Q, Amorphous Microring Resonator Sensors for Gaseous and Biological Species Detection

Manoharan, Krishna 27 April 2009 (has links)
No description available.
53

Rolled-up microtubes as components for Lab-on-a-Chip devices

Harazim, Stefan M. 29 November 2012 (has links) (PDF)
Rolled-up nanotechnology based on strain-engineering is a powerful tool to manufacture three-dimensional hollow structures made of virtually any kind of material on a large variety of substrates. The aim of this thesis is to address the key features of different on- and off-chip applications of rolled-up microtubes through modification of their basic framework. The modification of the framework pertains to the tubular structure, in particular the diameter of the microtube, and the material which it is made of, hence achieving different functionalities of the final rolled-up structure. The tuning of the microtube diameter which is adjusted to the individual size of an object allows on-chip studies of single cells in artificial narrow cavities, for example. Another modification of the framework is the addition of a catalytic layer which turns the microtube into a self-propelled catalytic micro-engine. Furthermore, the tuneability of the diameter can have applications ranging from nanotools for drilling into cells, to cargo transporters in microfluidic channels. Especially rolled-up microtubes based on low-cost and easy to deposit materials, such as silicon oxides, can enable the exploration of novel systems for several scientific topics. The main objective of this thesis is to combine microfluidic features of rolled-up structures with optical sensor capabilities of silicon oxide microtubes acting as optical ring resonators, and to integrate these into a Lab-on-a-Chip system. Therefore, a new concept of microfluidic integration is developed in order to establish an inexpensive, reliable and reproducible fabrication process which also sustains the optical capabilities of the microtubes. These integrated microtubes act as optofluidic refractrometric sensors which detect changes in the refractive index of analytes using photoluminescence spectroscopy. The thesis concludes with a demonstration of a functional portable sensor device with several integrated optofluidic sensors. / Die auf verspannten Dünnschichten basierende „rolled-up nanotechnologie“ ist eine leistungsfähige Methode um dreidimensionale hohle Strukturen (Mikroröhrchen) aus nahezu jeder Art von Material auf einer großen Vielfalt von Substraten herzustellen. Ausgehend von der Möglichkeit der Skalierung des Röhrchendurchmessers und der Modifikation der Funktionalität des Röhrchens durch Einsatz verschiedener Materialien und Oberflächenfunktionalisierungen kann eine große Anzahl an verschiedenen Anwendungen ermöglicht werden. Eine Anwendung behandelt unter anderem on-chip Studien einzelner Zellen wobei die Mikroröhrchen, an die Größe der Zelle angepasste, Reaktionscontainer darstellen. Eine weitere Modifikation der Funktionalität der Mikroröhrchen kann durch das Aufbringen einer katalytischen Schicht realisiert werden, wodurch das Mikroröhrchen zu einem selbstangetriebenen katalytischen Mikro-Motor wird. Hauptziel dieser Arbeit ist es Mikrometer große optisch aktive Glasröhrchen herzustellen, diese mikrofluidisch zu kontaktieren und als Sensoren in Lab-on-a-Chip Systeme zu integrieren. Die integrierten Glasröhrchen arbeiten als optofluidische Ringresonatoren, welche die Veränderungen des Brechungsindex von Fluiden im inneren des Röhrchens durch Änderungen im Evaneszenzfeld detektieren können. Die Funktionsfähigkeit eines Demonstrators wird mit verschiedenen Flüssigkeiten gezeigt, dabei kommt ein Fotolumineszenz Spektrometer zum Anregen des Evaneszenzfeldes und Auslesen des Signals zum Einsatz. Die entwickelte Integrationsmethode ist eine Basis für ein kostengünstiges, zuverlässiges und reproduzierbares Herstellungsverfahren von optofluidischen Mikrochips basierend auf optisch aktiven Mikroröhrchen.
54

Self-assembled rolled-up devices: towards on-chip sensor technologies

Smith, Elliot John 13 September 2011 (has links) (PDF)
By implementing the rolled-up microfabrication method based on strain engineering, several systems are investigated within the contents of this thesis. The structural morphing of planar geometries into three-dimensional structures opens up many doors for the creation of unique material configurations and devices. An exploration into several novel microsystems, encompassing various scientific subjects, is made and methods for on-chip integration of these devices are presented. The roll-up of a metal and oxide allows for a cylindrical hollow-core structure with a cladding layer composed of a multilayer stack, plasmonic metamaterial. This structure can be used as a platform for a number of optical metamaterial devices. By guiding light radially through this structure, a theoretical investigation into the system makeup of a rolled-up hyperlens, is given. Using the same design, but rather propagating light parallel to the cylinder, a novel device known as a metamaterial optical fiber is defined. This fiber allows light to be guided classically and plasmonically within a single device. These fibers are developed experimentally and are integrated into preexisting on-chip structures and characterized. A system known as lab-in-a-tube is introduced. The idea of lab-in-a-tube combines various rolled-up components into a single all-encompassing biosensor that can be used to detect and monitor single bio-organisms. The first device specifically tailored to this system is developed, flexible split-wall microtube resonator sensors. A method for the capturing of embryonic mouse cells into on-chip optical resonators is introduced. The sensor can optically detect, via photoluminescence, living cells confined within the resonator through the compression and expansion of a nanogap built within its walls. The rolled-up fabrication method is not limited to the well-investigated systems based on the roll-up from semiconductor material or from a photoresist layer. A new approach, relying on the delamination of polymers, is presented. This offers never-before-realized microscale structures and configurations. This includes novel magnetic configurations and flexible fluidic sensors which can be designed for on-chip and roving detector applications.
55

Rolled-up microtubes as components for Lab-on-a-Chip devices

Harazim, Stefan M. 09 November 2012 (has links)
Rolled-up nanotechnology based on strain-engineering is a powerful tool to manufacture three-dimensional hollow structures made of virtually any kind of material on a large variety of substrates. The aim of this thesis is to address the key features of different on- and off-chip applications of rolled-up microtubes through modification of their basic framework. The modification of the framework pertains to the tubular structure, in particular the diameter of the microtube, and the material which it is made of, hence achieving different functionalities of the final rolled-up structure. The tuning of the microtube diameter which is adjusted to the individual size of an object allows on-chip studies of single cells in artificial narrow cavities, for example. Another modification of the framework is the addition of a catalytic layer which turns the microtube into a self-propelled catalytic micro-engine. Furthermore, the tuneability of the diameter can have applications ranging from nanotools for drilling into cells, to cargo transporters in microfluidic channels. Especially rolled-up microtubes based on low-cost and easy to deposit materials, such as silicon oxides, can enable the exploration of novel systems for several scientific topics. The main objective of this thesis is to combine microfluidic features of rolled-up structures with optical sensor capabilities of silicon oxide microtubes acting as optical ring resonators, and to integrate these into a Lab-on-a-Chip system. Therefore, a new concept of microfluidic integration is developed in order to establish an inexpensive, reliable and reproducible fabrication process which also sustains the optical capabilities of the microtubes. These integrated microtubes act as optofluidic refractrometric sensors which detect changes in the refractive index of analytes using photoluminescence spectroscopy. The thesis concludes with a demonstration of a functional portable sensor device with several integrated optofluidic sensors. / Die auf verspannten Dünnschichten basierende „rolled-up nanotechnologie“ ist eine leistungsfähige Methode um dreidimensionale hohle Strukturen (Mikroröhrchen) aus nahezu jeder Art von Material auf einer großen Vielfalt von Substraten herzustellen. Ausgehend von der Möglichkeit der Skalierung des Röhrchendurchmessers und der Modifikation der Funktionalität des Röhrchens durch Einsatz verschiedener Materialien und Oberflächenfunktionalisierungen kann eine große Anzahl an verschiedenen Anwendungen ermöglicht werden. Eine Anwendung behandelt unter anderem on-chip Studien einzelner Zellen wobei die Mikroröhrchen, an die Größe der Zelle angepasste, Reaktionscontainer darstellen. Eine weitere Modifikation der Funktionalität der Mikroröhrchen kann durch das Aufbringen einer katalytischen Schicht realisiert werden, wodurch das Mikroröhrchen zu einem selbstangetriebenen katalytischen Mikro-Motor wird. Hauptziel dieser Arbeit ist es Mikrometer große optisch aktive Glasröhrchen herzustellen, diese mikrofluidisch zu kontaktieren und als Sensoren in Lab-on-a-Chip Systeme zu integrieren. Die integrierten Glasröhrchen arbeiten als optofluidische Ringresonatoren, welche die Veränderungen des Brechungsindex von Fluiden im inneren des Röhrchens durch Änderungen im Evaneszenzfeld detektieren können. Die Funktionsfähigkeit eines Demonstrators wird mit verschiedenen Flüssigkeiten gezeigt, dabei kommt ein Fotolumineszenz Spektrometer zum Anregen des Evaneszenzfeldes und Auslesen des Signals zum Einsatz. Die entwickelte Integrationsmethode ist eine Basis für ein kostengünstiges, zuverlässiges und reproduzierbares Herstellungsverfahren von optofluidischen Mikrochips basierend auf optisch aktiven Mikroröhrchen.
56

Self-assembled rolled-up devices: towards on-chip sensor technologies

Smith, Elliot John 29 August 2011 (has links)
By implementing the rolled-up microfabrication method based on strain engineering, several systems are investigated within the contents of this thesis. The structural morphing of planar geometries into three-dimensional structures opens up many doors for the creation of unique material configurations and devices. An exploration into several novel microsystems, encompassing various scientific subjects, is made and methods for on-chip integration of these devices are presented. The roll-up of a metal and oxide allows for a cylindrical hollow-core structure with a cladding layer composed of a multilayer stack, plasmonic metamaterial. This structure can be used as a platform for a number of optical metamaterial devices. By guiding light radially through this structure, a theoretical investigation into the system makeup of a rolled-up hyperlens, is given. Using the same design, but rather propagating light parallel to the cylinder, a novel device known as a metamaterial optical fiber is defined. This fiber allows light to be guided classically and plasmonically within a single device. These fibers are developed experimentally and are integrated into preexisting on-chip structures and characterized. A system known as lab-in-a-tube is introduced. The idea of lab-in-a-tube combines various rolled-up components into a single all-encompassing biosensor that can be used to detect and monitor single bio-organisms. The first device specifically tailored to this system is developed, flexible split-wall microtube resonator sensors. A method for the capturing of embryonic mouse cells into on-chip optical resonators is introduced. The sensor can optically detect, via photoluminescence, living cells confined within the resonator through the compression and expansion of a nanogap built within its walls. The rolled-up fabrication method is not limited to the well-investigated systems based on the roll-up from semiconductor material or from a photoresist layer. A new approach, relying on the delamination of polymers, is presented. This offers never-before-realized microscale structures and configurations. This includes novel magnetic configurations and flexible fluidic sensors which can be designed for on-chip and roving detector applications.

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