Abstract
Single photons are a promising candidate for use in a wide range of quantum technologies such as quantum communications, quantum imaging and quantum computing. There is still plenty of improvement required from existing single-photon sources, however, to meet the requirements of these technologies if they are to find use in the real world. One particular platform which lends itself to the role is the photonic crystal fibre, a type of optical fibre in which four-wave-mixing, a photon-pair generation process, can be engineered and harnessed. Like all proposed platforms, there are difficulties with this method including contributors of noise and natural variations along the fibre length being detrimental to the source's performance.This thesis examines an existing photon pair source in an all-fibre architecture, to reveal Raman scattering as the primary source of noise. Other points of improvement, such as minimising fibre-fibre interface loss, better mode-matching and improving sensitivity towards fabrication-induced structural variations, motivate a new design of fibre which can address these issues. This thesis then presents a hybrid optical fibre design which marries index-guiding photonic crystal fibre with photonic bandgap photonic crystal fibre. In doing so, the fibre is able to realise a four-wave-mixing scheme which generates photon pairs with factorable spectra at 810 and 1550 nm for a pump at 1064 nm, whilst removing Raman-scattered noise at 1115 nm. The general framework for designing such a fibre, and the resulting behaviour's dependence upon the fibre's structural parameters, is presented.
| Date of Award | 1 Nov 2021 |
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| Original language | English |
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| Supervisor | Peter Mosley (Supervisor) & Joshua Nunn (Supervisor) |