Abstract
The research I present in this thesis is a collection of recent developments of endoscopic optical fibre technology, focussing primarily on my contributions to the field of bronchoscopy.The bulk of my PhD has been spent advancing the coherent fibre bundle technology that is used prolifically for endoscopic imaging. This was achieved by controlling the core-to-core crosstalk that is the primary mechanism of image quality degradation. In this thesis I report novel methods of fabricating several lower cost but high performance imaging fibres that use regular lattices of different sized cores to suppress coupling. Ultimately, I detail my methods of fabricating a new class of imaging fibre that uses an air-filled cladding to better confine the light to its cores. I go on to show that this type of fibre offers 3.2 µm resolution, competitive with leading commercial alternatives, but functions up to wavelengths in excess of 1500 nm. These fibres can also be drawn thinner or post-processed to provide resolutions down to 2.2 µm, superior to any silica based imaging fibres currently on the market.
In addition to using a selection of established techniques to measure and compare the performance of my imaging fibres, I also use a technique of my own design that uses an interference pattern of filtered supercontinuum light as the standard image. This allows the fibre’s performance to be quantified across a wide spectrum of optical and spatial frequencies.
The prospect of including a fibre designed for sensing the chemical environment (such as pH and oxygen saturation) of the distal end of the endoscope is currently a subject of great interest to the optical fibre field. The associated challenges and some potential solutions that have been developed by my group are also discussed in this thesis.
| Date of Award | 1 May 2019 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Tim Birks (Supervisor) & Jonathan Knight (Supervisor) |
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