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 153 for “"optical fibre"”.
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Optical fibre nanowire devices
The Optical Fibre Nanowire (OFN) is a potential building block in future micro- and nano-photonic device since it offers a number of unique optical and mechanical properties. In this thesis, the background and fundamental features of nanowires are introduced; the theory, design and demonstration of …
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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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Ultra-long haul optical fibre transmission systems
This thesis examines experimentally options for optical fibre transmission over oceanic distances. Its format follows the chronological evolution of ultra-long haul optical systems, commencing with opto-electronic regenerators as repeaters, progressing to optically amplified NRZ systems and finally …
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Machine Learning for Optical Fibre Communication Systems
… This continued growth is exerting pressure on optical fibre communication systems and networks, which carry the bulk of modern internet traffic, leading to a risk of a capacity crunch. The overarching goal of this thesis is to alleviate this pressure by increasing the capacity of optical fibre …
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Mechanical performance of optical fibre cable: A theoretical and practical analysis to establish advanced design rules for optical fibre cables.
… investigates the properties which influence optical fibre cable life. Four mechanical properties have been investigated, two general, crush and temperature, and two specifically associated with aerial cables, namely electrical degradation and shotgun damage. In addition to these mechanical …
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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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Modelling of optical fibre long-period grafting sensors.
… thesis a mathematical model of the long-period fibre grating (LPG) sensor has been developed. Numerical simulation of the LPG transmission spectrum behavior is studied when changing the refractive index of the ambient. The attenuation bands are seen to shift to shorter wavelengths as the …
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Advanced waveguides for high power optical fibre sources
… Nd<sup>3+</sup>- and Yb<sup>3+</sup>-doped fibre lasers. Cladding-pumped high-power fibre lasers based on these novel waveguide designs and operating at desired unconventional wavelengths were investigated through numerical simulations and fibre laser experiments.<br/>Rare earth doped fibres …
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Estimating the Performance of Optical Fibre Communication Systems
… in demand for reliable and economically viable optical communication systems has increased the research into improving their capacity. In light of the wide availability of data generated by these systems and the complexity of their operation given the associated non-linearities, we employ …
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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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Optimising the plastic optical fibre evanescent field biofilm sensor
… application of large diameter multimode plastic optical fibre (POF) sensors using evanescent field modulation. The exposed polymethylmethacrylate (PMMA) core of the POF fibre forms the sensor interface that detects refractive index changes of a measurand acting as the cladding. When a liquid …
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Optical fibre-based minimally-invasive blood glucose monitoring system.
… an alternative solution. This thesis shows that optical fibre can act both as a sensing element and a medium to carry information in real time. Optical methods are useful as they require a very small sample volume (< 1 μL) and are also capable of remote probing. An investigation into various …
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Survivability and resilience mechanisms in modern optical fibre systems
Optical fibre networks play an increasingly prominent role in communications. As networks grow in size and complexity, the probability and impact of failures increase. In this dissertation, different optical network concepts, survivability and resilience methods are considered. Link and Path …
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Low-cost interrogation of optical fibre Bragg grating sensors
… measurement capabilities of a scalable low-cost fibre Bragg grating sensor network. This network has been shown to be comparable with the performance of existing fibre Bragg grating sensing techniques, at a greatly reduced implementation cost.
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Optical fibre communication over a noisy partially coherent channel
As global IP traffic grows unceasingly, optical networks demand for technology upgrades in order to keep the feared “capacity crunch” away. The most celebrated technologies of coherent detection and wavelength-division multiplexing (WDM), widely deployed in long-haul links, are gaining ground in …
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Interferometric optical fibre sensor for highway pavements and civil structures
Optical fibres have been used for developing variety of sensing configurations for monitoring a wide range of parameters. This thesis presents the design, construction and characterisation of a new type of single-transducer optical fibre Weigh-ln-Motion (WIM) sensor. The sensor is based on an …
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