Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"Fibre Bragg Gratings"”.
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Microscopic characterisation of fibre Bragg gratings
… study of microscopic characterization of optical fibres and fibre Bragg gratings, by the use of a non-invasive microscopic technique, namely differential interference contrast microscopy. The thesis aims to provide detailed information on the structural and optical properties of optical fibres and …
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Fabrication and applications of fibre Bragg gratings
The consequences of fabricating Bragg gratings in various fibres, with or without hydrogen loading, and with varying laser power levels are explored. Three new techniques for fabricating chirped gratings are presented. Beams with dissimilar wavefront curvatures are interfered to give chirped …
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Intragrating sensing using chirped optical fibre Bragg gratings
… intragrating sensing systems employing chirped fibre Bragg gratings (CFBGs) are investigated. Intragrating sensing is the process of obtaining a continuous profile of a measurand over the grating length from either the amplitude or phase, or both the amplitude and phase of its measured …
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Fibre bragg gratings for microwave photonics and sensing
… of microwave transversal filters using fibre Bragg grating arrays and the building of fibre Bragg grating based magnetic-field sensors. Some theoretical background about fibre Bragg gratings, photosensitivity, fibre Bragg grating sensors and filters are presented. Fibre Bragg grating …
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Microscopic and spectral characterisation of optical Fibre Bragg gratings
Fibre Bragg gratings (FBGs) have found extensive application in lasers, amplifiers, signal filtering in telecommunications and sensing. The underlying mechanisms and fundamental properties of FBGs are not completely understood, which stands in the way of full exploitation of FBG-based devices …
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Fabrication and application of short and novel structure in-fibre Bragg gratings
… and application of short and novel structure fibre Bragg gratings. The basic theoretical concepts of in-fibre Bragg gratings and photosensitive mechanisms are introduced together with an overview of fabrication methods and applications presented to date. The fabrication of fibre Bragg gratings …
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The use of loop mirrors and chirped fibre Bragg gratings in actively-modelocked fibre lasers
… hardware. This thesis presents several novel fibre lasers which are useful pulse sources for high speed optical data processing and communications. They share several attributes in common: flexibility, stability and low-jitter output. They all produce short (picosecond) and are suitable as …
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Applications of superstructure fibre Bragg gratings for optical code division multiple access and packet switched networks
… and recognition based on superstructure fibre Bragg grating (SSFBG) for use in Optical Code Division Multiple Access (OCDMA) systems and also in high-speed all-optical packet switched networks.These results highlight the precision and flexibility of the continuous grating writing process …
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In-situ deformation monitoring of aerospace qualified composites with embedded improved draw tower fibre Bragg gratings
Aerospace certified fibre reinforced plastics (FRPs) are extreme performing construction materials, which today are increasingly applied in primary structures of the new generation aircrafts (e.g. Boeing 787, Airbus 350, Bombardier C-Series), such as the fuselage, the wings and the fin. An …
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An investigation of phase-mask diffraction patterns and fibre Bragg gratings with scanning near-field optical microscopy
… of the optical and structural properties of fibre Bragg gratings, which are used throughout the optical fibre telecommunications network. By imaging the evanescent fields of Bragg gratings, a characterization technique has been developed which has enabled the acquisition of sub-wavelength …
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Investigation of code reconfigurable fibre Bragg gratings for Optical Code Division Multiple Access (OCDMA) and Optical Packet Switching (OPS) Networks
… and all-optical packet switching nodes based on fibre Bragg grating (FBG) technology. My research work involves characterizing the performance of various gratings, specifically high reflectivity, short chip duration, long code sequences, multiple phase level and tunable superstructured fiber …
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Optical fibre sensors and their interrogation
… in the fabrication and understanding of type IA fibre Bragg gratings, the uses of said gratings as optical sensors and the interrogation of optical sensors using tilted fibre Bragg gratings. This thesis presents the most detailed study of type IA gratings performed to date and provides the basis …
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Damage detection in composite materials using acoustic emission and self-sensing fibres
… of acoustic emission testing and self-sensing fibres to detect damage in composite materials. This was achieved by performing acoustic emission testing on fibre samples and resin samples during tensile tests. In parallel to the acoustic emission testing the changes in strain for the resin …
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Fibre gratings in novel optical fibres for applications in sensing
This thesis presents the fabrication of fibre gratings in novel optical fibres for sensing applications. Long period gratings have been inscribed into photonic crystal fibre using the electric-arc technique. The resulting sensing characteristics were found to depend on the air-hole geometry of the …
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Advanced Fibre Bragg Grating fabrication systems and devices
This thesis address the creation of fibre Bragg grating based sensors and the fabrication systems which are used to manufacture them. The information is presented primarily with experimental evidence, backed up with the current theoretical concepts. The issues involved in fabricating high quality …
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A theoretical study into the fundamental design limits of devices based on one-and two-dimensional structured fibres
… latest key technologies used to produce optical fibre devices for telecommunication system applications. The first technology (fibre Bragg gratings) concerns the 1-dimensional perturbation of the refractive index of an optical fibre (i.e. along the propagation axis of the fibre), whereas the …
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Optical fibre refractive index, voltage and strain sensors : fabrication and applications
… study of intensity and wavelength-based optical fibre sensors (OFSs) for various applications in three major sensing areas: refractive index (RI), voltage and strain. The thesis aims to provide detailed information on the design and performance of particular intensity-based and wavelength-based …
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Advanced optical techniques for high capacity transmission
… systems. The basic theory of optical fibre communications are introduced before optical solitons and their usage in optically amplified fibre systems are discussed. The design, operation, limitations and importance of the recirculating loop are illustrated. The crucial role of …
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