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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.
1

Investigation of Energy Coupling between Laser Diodes and Tapered Fibers, 2-D Case

Lee, Shun-Tien 30 June 2000 (has links)
Abstract Optical fiber communications have been become one of the most popular researches since 1970s. In this field, there are many studies on the coupling between semiconductor lasers and fibers and many conclusions are demonstrated. In this thesis we build a 2-D numerical model to simulate energy coupling between laser diodes (LDs) and tapered optical fibers. Our model is based on the spectral domain integral equation (SDIE) formulation which is derived from Maxwell equations and the principle of mode matching. Through this numerical model we will be able to show the field distribution in LD waveguide junctions. We may also use this tool to study the coupling parameters such as the separation distance and tapered fiber geometry.
2

Tapered Optical Fiber Platform for High Sensitivity Refractive Index Sensing Applications

Ben Harush Negari, Amit January 2014 (has links)
No description available.
3

The Effects of Diameter Fluctuations and Coiling on the Sensitivity of Sapphire Single Crystal Optical Fiber Evanescent Wave Fluorescence Sensors

Gamez, Jimmy Ray 10 April 2009 (has links)
The purpose of this research was to determine the effect of diameter fluctuations on the sensitivity of sapphire multimode optical fibers used as evanescent wave fluorescence sensors. It was predicted that fluctuations in the diameter of the fiber would act as a series of bi-tapers converting lower order modes to higher order modes increasing the evanescent wave penetration depth thereby increasing the excitation of a cladding of fluorescent fluid. Induced fluorescence from the fluid cladding would then couple back into the fiber more efficiently increasing the sensitivity of the sensor. The effect of coiling the fiber on the sensitivity of the sensor was also explored. Coiling the fiber converts lower order modes into higher order modes and increases the sensing length while maintaining a small probe size. However, coiling experiments produced unexpected results and in the course of studying these results a layer of material was discovered coating the surface of the sapphire fibers.
4

3D Printed Mounts for Liquid Microdroplet Resonators

Awerkamp, Parker A. 30 July 2024 (has links) (PDF)
Liquid microdroplet resonators provide an excellent tool for optical studies due to their innate smoothness and high quality factors, but they can be difficult to control. By using 3D printed mounts to support the droplets, we can obtain precise control over the droplet geometries and positions. We here present our work with oil, water, and ice microdroplets, as well as tools required to enable their study. We first present methods for creating 3D printed mounts for oil microdroplet resonators. The mounts enable precise positioning of the droplets relative to a tapered optical fiber. The oil microdroplet resonators exhibited quality factors of over 4 × 10^5. Water microdroplet resonators are more difficult to create due to the evaporation of water. By supporting the droplet on a 3D printed structure that supplies water to the droplet, we can maintain a water microdroplet resonator in an ambient environment while also controlling its shape and size. The resulting resonators have high quality factors, with values measured as high as 6 × 10^8. Ice microdroplets may be useful as optical resonators; however, typically ice appears cloudy due to trapped air bubbles. We present a method for freezing clear ice microdroplets in both humid and dry environments, enabling the formation of a clear ice droplet without the risk of additional crystal growth. To facilitate the freezing of droplets in a low-humidity environment, we have developed an environmental control chamber capable of maintaining an arbitrary humidity level and controlling the temperature of a small sample. We here present instructions for its manufacture as well as validation of its function. Finally, we present an automated fabrication system for the creation of tapered and dimpled optical fibers. Tapered fibers have been essential in our work as tools for optical coupling to microdroplet resonators, and dimpled fibers allow for coupling to on-chip structures. The system we present allows for their fabrication with no user input and is able to produce fibers with efficiencies over 90% at a high yield.
5

Kombinované struktury v optickém vlákně / The combined structures in optical fiber

Klvaňa, Jakub January 2017 (has links)
The aim of this master’s thesis is familiar with the problems of optical fibers and possi- bilities creating functional optical structures in optical fibers. first section focuses on the optical fibers and their properties. Another chapter deals with the functional structures of optical fiber and their production. Next section is devoted to the analysis of combinations of these functional structures and their potential applications in sensors. Subsequently, a combined structure is proposed, which is later produced, measured and evaluated for possible use in the sensors

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