Guidance of light in hollow-core optical fibres

Over the past five years there has been a remarkable surge of interest in a new generation of optical fibres that has considerable potential for novel applications in areas such as high power delivery and gas lasers. In these fibres, light propagates in an air core which has a diameter of order ten times the wavelength. They have a very low attenuation coefficient, which at first sight is surprising because there are no localised modes and the light is propagating in an unbound state.

The overall aim of the project is to gain a deeper understanding of why these fibres guide light so effectively, and to use this to support the design of new fibre structures. Although the basic guidance mechanism is understood (anti-resonant reflection from elements of the fine cladding structure that surrounds the air core), there are many details that are far from clear. For example – why does the shape of the central air core have such a large effect on the loss of the fibre? Large scale computations have provided some insight into this and other questions, but such a black-box approach does not provide the level of understanding that is needed to generate new designs with potentially record-breaking low loss.

The student will develop theoretical and computational tools to analyse the guidance and loss mechanisms of these fibres. Starting with a range of model structures, they will use perturbative methods to understand how the loss depends on the size and shape of the core, the surrounding cladding structure, the material properties, etc. In conjunction with analytical work, they will also develop computational methodologies that are particularly well suited to calculating the properties of these fibres.

The project will be carried out within the Centre for Photonics and Photonic Materials, which is internationally recognised for its expertise in the development and application of novel optical fibres. The Centre provides a well-resourced and lively research environment and, along with the Physics department and the University, offers many opportunities for training and development. The student will interact strongly with other PhD students and post-docs working on related projects including those making, measuring and using hollow-core optical fibres. During the course of the project they will develop their mathematical and programming skills, which are highly sought after for future employment in research and industry. They will also have opportunities to present their work at informal meetings and at conferences, and to publish in high-quality, peer-reviewed journals.

Applicants will need strong mathematical and computational skills, and have or expect to gain a First or good Upper Second class Honours degree in Physics, Mathematics or an Engineering discipline.

Informal enquiries should be directed to Prof David Bird ([Email Address Removed])

Formal applications should be made via the University of Bath’s online application form for a PhD in Physics:
https://www.bath.ac.uk/samis/urd/sits.urd/run/siw_ipp_lgn.login?process=siw_ipp_app&code1=RDUPH-FP01&code2=0012

More information about applying for a PhD at Bath may be found here:
http://www.bath.ac.uk/guides/how-to-apply-for-doctoral-study/

Anticipated start date: 1 October 2018